MULTIPLE CHOICE QUESTIONS IN: Encoded By

MULTIPLE CHOICE QUESTIONS IN:

Test yourself- Exam 1-10 Noise Chapter 4 Antennas Chapter 6 Satellite Communications Chapter 10 Optical Fiber Communications Broadcasting Microwave Communications Acoustics Radiation and wave propagation Transmission Fundamentals Wire and Wireless Communications – Chapter 7 Modulation – Chapter 3

Encoded By: Garcia, Frederick P. Cagaoan, Neil Mendoza, Darren Puro, Genara Mhariz P. Tan, Virson V. Visaya, Luz Regine B.

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ECE Board Exam March 1996 That dielectric material of an optical fiber surrounding the core A. Cladding B. Armor C. Shield D. Cover ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop ECE Board Exam March 1996 A word in telegraphy consist of __________ characters plus a word space. A. 11 B. 7 and ½ C. 8 D. 5 ECE Board Exam March 1996 The number of voice band channels in master group per CCITT standard is __________. A. 300 B. 480 C. 600 D. 120 ECE Board Exam March 1996 The power of standard test tone is normally ____________. A. 1 dB B. 0 mW C. 1 mW D. 1 W ECE Board Exam March 1996 LORAN is a navigational system used primarily for _____________. A. blind landing B. obtaining your fixes location over large distances C. automatic collision warning D. approach control ECE Board Exam March 1996 The expander in a companding device provides ___________. A. greater amplification for low signal levels

B. less amplification for low signal levels C. greater amplification for high signal levels D. lesser pressure for transmission cables 8. ECE Board Exam March 1996 LORAN is a navigation system used primarily for A. approach control B. obtaining fixes over large distances C. blind landing D. automatic collision warning 9. ECE Board Exam March 1996 At what power level does a 1 kHz tone cause zero interference (144 weighted) ? A. -90 dB B. -90 dBm C. 90 dBm D. 90 dB 10. ECE Board Exam March 1996 One character or a sequence of characters forming a part, or the whole of a message with a specific meaning A. Signs B. Call sign C. Code D. Identifier 11. ECE Board Exam March 1996 The K-factor under normal atmospheric conditions in a microwave radio data profile calculation is equal to ___________. A. 2/3 B. 0 C. 4/3 D. Infinity 12. ECE Board Exam March 1996 What is the IBM’s asynchronous data link protocol designation? A. 83 B B. 8A1 / 8B1 C. 93 B D. 9A1/ 9B1 13. ECE Board Exam March 1996 EIRP stands for _______________. A. effective isotropic refracted power B. effective and ideal radiated power C. effective isotropic reflected power

D. effective isotropic radiated power 14. ECE Board Exam March 1996 The modulation system used for telegraphy is A. frequency-shift keying B. two-tone modulation C. pulse-code modulation D. single-tone modulation 15. ECE Board Exam March 1996 The standard that specifies a balanced interface cable that will operate bit rates up to 10 Mbps with in a span distances up to 1200 m. A. RS-423A B. RS-422A C. RS-550A D. RS-449A 16. ECE Board Exam March 1996 An antenna which is not resonant at a particular frequencies and so can be used over a wide band of frequencies and so can be used over a wide band of frequencies is called A. aperiodic B. boresight C. cassegrain D. top-loaded 17. ECE Board Exam March 1996 A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise resistance of 30 ohms. What is the receiver’s noise temperature? A. 754 K B. 464 K C. 174 K D. 293 K 18. ECE Board Exam March 1996 ___________ occurs when the microwave beam is at point of grazing over an obstacle. A. Diffraction B. Refraction C. Absorption D. Reflection 19. ECE Board Exam March 1996 Atmospheric condition is controlled by A. humidity B. pressure C. temperature D. all of these

20. ECE Board Exam March 1996 The characteristics impedance of a transmission line does not depend upon its ________. A. conductor spacing B. conductor diameter C. length D. conductor radius 21. ECE Board Exam March 1996 What is the purpose of a beat frequency oscillator (BFO)? A. Aid in the reception of weak voice-modulated signals B. Generates a signal, whose frequency is the same as that of the intermediate frequency C. Generates a 1kHz note for Morse code reception D. Generates an output, whose frequency differs from that of the intermediate frequency by 1 kHz 22. ECE Board Exam March 1996 The point on the satellite orbit, closest to the earth is A. prograde B. perigee C. zenith D. apogee 23. ECE Board Exam March 1996 The potential difference between any exposed structured to ground in any electrical installation should not exceed _________ volts RMS. A. 10 B. 45 C. 0 D. 30 24. ECE Board Exam March 1996 The capture area of an antenna is directly proportional to the A. frequency of the received signal B. distance between transmitter and receiver C. gain of the antenna D. power density of the signal 25. ECE Board Exam March 1996 Modems are required to connect computer to telephone lines because ___________. A. telephone company rules required them B. the telephone network bandwidth is too high C. none of the above D. the telephone network will pass direct current 26. ECE Board Exam March 1996 The standard reference antenna for the directive gain is ___________.

A. elementary doublet B. isotropic antenna C. half-wave dipole D. infinitesimal dipole 27. ECE Board Exam March 1996 One hundred twenty µbars of pressure variation is equal to A. 120 dBSPL B. 115.56 dBSPL C. 41.58 dBSPL D. 57.78 dBSPL 28. ECE Board Exam March 1996 It is a spacecraft placed in orbit around the earth carrying onboard microwave receiver and transmitting equipments. A. Fiber optic equipment B. Communications satellite C. Wireless radio system D. Coaxial cable syste 29. ECE Board Exam March 1996 One type of pulse communications system uses pulse that appear as a group, and which vary in number according to the loudness of the voice. This type of pulse modulation is called A. pulse duration modulation B. pulse amplitude modulation C. pulse code modulation D. pulse position modulation 30. ECE Board Exam March 1996 A device to be connected across the headset in telephone receivers to reduce the effects of acoustic shock. A. Ground B. Two rectifiers in parallel with opposite polarities C. Protector D. Fuse 31. ECE Board Exam March 1996 Judgment on the case against an ECE shall become final and executory after A. 10 days B. 60 days C. 30 days D. 15 days 32. ECE Board Exam March 1996 The equivalent noise temperature of the amplifier is 25 K. What is the noise figure?

A. 1.86 B. 0.1086 C. 1.086 D. 10.86 33. ECE Board Exam March 1996 The letter-number designation B8E is a form of modulation also known as ___________. A. pilot carrier system B. independent sideband emission C. lincomplex D. vestigial sideband transmission 34. ECE Board Exam March 1996 When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ________ wave. A. space or direct B. ground C. surface D. sky 35. ECE Board Exam March 1996 Crosstalk coupling is ___________. A. dBm (disturbing pair) minus dBm (disturbed pair) B. the difference between readings on a cable pair with a tone and a cable pair without tone read at the far end of a cable C. signals from one circuit that get into another circuit D. All of these are true 36. ECE Board Exam March 1996 According to the Nyquist theorem, the sampling rate that can be used in a PCM system is ________ the highest audio frequency. A. once B. eight times C. twice D. thrice 37. ECE Board Exam March 1996 Passive crossover components cause some frequencies to be delayed with respect to the other frequencies at the crossover point. A. Phase shift B. Phase correction C. Phase-error correction D. Time alignment 38. ECE Board Exam March 1996

A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this distance, what is the sound power in watt? A. 12 W B. 0.12 W C. 0.012 W D. 1.2 W 39. ECE Board Exam March 1996 What is the one principal difference between synchronous and asynchronous transmission? A. the pulse height are different B. the clocking is derived from the data in synchronous transmission C. the clocking is mixed with the data in asynchronous D. the bandwidth required is different 40. ECE Board Exam March 1996 The lowest layer in the ionosphere A. D B. F2 C. E D. F1 41. ECE Board Exam March 1996 What is the number of pins in the RS-232C interface? A. 25 B. 15 C. 20 D. 20 42. ECE Board Exam March 1996 SSB transmission requires only ______ of the bandwidth for a DSBFC transmission. A. ¼ B. 2/3 C. ½ D. ¾ 43. ECE Board Exam March 1996 The method of generating FM used by broadcasting station is A. direct B. all of these C. indirect D. insertion 44. ECE Board Exam March 1996

What is the transmission rate of a system for transmitting the output of a microcomputer to a line printer operating at a speed of 30 lines/minute? Assume that the line printer has 8 bits of data per character and prints out 80 characters/line. A. 800 bps B. 400 bps C. 320 bps D. 640 bps 45. ECE Board Exam March 1996 Communications code is ____________. A. eight bits per character B. agreed upon in advance between sender and receiver C. the same in all modern computers D. either seven or eight bits per character 46. ECE Board Exam March 1996 What is the reference tone level for dBm? A. -82 dBm B. -85 dBm C. -67 dBm D. -90 dBm 47. ECE Board Exam March 1996 A type of an underground antenna is a/an __________ antenna. A. Hertz B. isotropic C. parabolic D. Marconi 48. ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM 49. ECE Board Exam March 1996 What is the purpose of the receiver’s squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent fluctuations in the AGC bias level C. To reduce the receiver’s sensitivity to all incoming signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal 50. ECE Board Exam March 1996 TACAN is a navigational aid providing ___________.

A. bearing and distance indication B. speed and height indication C. bearing and weather information D. instrument-landing glide paths 51. ECE Board Exam March 1996 In __________ transmission, a unique SYNC character is transmitted at the beginning of each message. A. asynchronous B. synchronous C. digital D. analogue 52. ECE Board Exam March 1996 If the terminating impedance is exactly equal to the characteristic impedance of the transmission line the return loss is ___________. A. zero B. one C. infinite D. None of these 53. ECE Board Exam March 1996 What is the main purpose of a communications system? A. None of these B. To have a frequency assignment C. For modulation D. To provide an acceptable replica of the information at the destination 54. ECE Board Exam March 1996 What is meant by antenna gain? A. The final amplifier gain minus the transmission line losses (including any phasing lines present) B. The ratio of the amount of power produced by the antenna compared to the output power of the transmitter C. The ratio of the signal in the backward direction D. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna 55. ECE Board Exam March 1996 Binary communications systems are better because A. they can interface directly with the analog telephone network B. the components are simpler, less costly, and more reliable C. people think better in binary D. interstate calls are less costly

56. ECE Board Exam March 1996 In the phase shift method, How many circuits must be balanced? A. None of these B. 1 C. 4 D. 2 57. ECE Board Exam March 1996 The carrier swing necessary to provide 80% modulation in the FM broadcasting band is __________. A. 150 kHz B. 120 kHz C. 60 kHz D. 75 kHz 58. ECE Board Exam March 1996 The correctness and accuracy of the transmitted message content is A. verified by the modem B. communications system C. determined by the sender and receiver D. ensured by use of digital technique 59. ECE Board Exam March 1996 The signal in a channel is measured to be 23 dB while noise in the same channel is measured to be 9 dB. The signal to noise ratio therefore is __________. A. 9/23 B. 23/9 C. 32 dB D. 14 dB 60. ECE Board Exam March 1996 Three audio waves with 100,200 and 300 volts amplitude respectively, simultaneously modulate a 450 volts carrier. What is the total percent of modulation of the AM wave? A. 69 % B. 115.5 % C. 50% D. 83% 61. ECE Board Exam March 1996 If the percentage modulation of an AM amplifier is 88% and the modulating signal is 1 volt, the carrier has an amplitude of _______________. A. 1.14 volts B. 0.88 volt C. 1.88 volts D. 0.12 volt

62. ECE Board Exam March 1996 It consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source. A. Log-periodic antenna B. Yagi antenna C. End-fire array D. Broadside array 63. ECE Board Exam March 1996 Data switching systems. A. improve the efficiency of data transfer B. are limited to small data networks C. required additional lines D. are not used in data system 64. ECE Board Exam March 1996 A type of array antenna which consists of one half-wave driven dipole, one reflector and one director A. Hertzian dipole B. Yagi-uda C. Broadside collinear D. Log periodic dipole array 65. ECE Board Exam March 1996 Power is a _____________ amount of energy used in specific period of time A. large B. definite C. electrical D. relative 66. ECE Board Exam March 1996 The midrange frequency range of sound is from A. 256 to 2048 Hz B. 2048 to 4096 Hz C. 512 to 2048 Hz D. 16 to 64 Hz 67. ECE Board Exam March 1996 To connect coaxial line to a parallel-wire _________ is the best to use. A. directional coupler B. quarter-wave transformer C. balun D. slotted line 68. ECE Board Exam March 1996 In AM, the carrier carries ____________ intelligence.

A. no B. difference C. distorted D. same 69. ECE Board Exam March 1996 Characteristics impedance of a transmission line is the impedance measured at the ___________ when its length is infinite. A. input B. shorted end of the line C. output D. midsection 70. ECE Board Exam March 1996 Cross modulation on a receiver is eliminated at the A. RF stage B. mixer stage C. IF stage D. detector stage 71. ECE Board Exam March 1996 A speaker cabinet has an internal volume 84,950 cm3. It has a port area on the baffle of 3,230 cm2 and baffle thickness of 19 mm. What is the Helmholtz resonance hertz of this speaker enclosure? A. 260 Hz B. 245 Hz C. 265 Hz D. 250 Hz 72. ECE Board Exam March 1996 What quarterwave transformer will match a 100Ω line to an antenna whose value is 175Ω? A. 132.29 Ω B. 150 Ω C. 16.58 Ω D. 137.5 Ω 73. ECE Board Exam March 1996 The local loop of the telephone system is understood to be A. a single piece of wire connecting the subscriber’s telephone set to another telephone set in an adjacent room B. a two-wire or four-wire communication circuit between the customer’s premise and central office C. a four-wire circuit connecting a facsimile machine to a computer D. a group of wires connecting a telephone set to a modem

74. ECE Board Exam March 1996 In what region of the world is sporadic-E most prevalent? A. The equatorial regions B. The northern hemisphere C. The arctic regions D. The polar regions 75. ECE Board Exam March 1996 The process of assigning PCM codes to absolute magnitudes A. Overloading B. All of these C. Quantizing D. Multiplexing 76. ECE Board Exam March 1996 It is a measure of the microwave power radiated from an antenna as a function of angular direction from the antenna axis. A. Antenna pattern B. Polarization C. Beamwidth D. Sidelobes 77. ECE Board Exam March 1996 It is the made from semiconductor material such as aluminum-galium-arsenide or gallium-arsenide-phosphide. A. APD B. Injection laser diode C. Light emitting diode D. Positive-intrinsic-negative 78. ECE Board Exam March 1996 Which one is not the basic electrical protection measures in the Philippine Electronics Code? A. Voltage/ current limiting and interrupting B. Undergrounding C. Grounding and bonding D. Shielding 79. ECE Board Exam March 1996 What does the noise weighting curve shows? A. Noise signals measured with a 144 handset B. Power levels of noise found in carrier systems C. The interfering effect of other frequencies in a voice channel compared with a reference frequency of one kilohertz D. Interfering effects of signals compared with a 3-kHz tone

80. ECE Board Exam March 1996 What is the difference between phase and frequency modulation? A. Is purely theoretical because they are the same in practice B. Lies in poorer audio response of phase modulation C. Lies in the different definitions of the modulation index D. Is too great to make two systems compatible 81. ECE Board Exam March 1996 When a transmission line uses ground return, it is called a/an __________ line. A. ungrounded B. balanced C. unbalanced D. grounded 82. ECE Board Exam March 1996 What is the gain of four identically polarized antennas stacked one above the other and fed in phase? A. 3 dB over the gain of one antenna B. 10 dB over the gain of one antenna C. 4 dB over the gain of one antenna D. 6 dB over the gain of one antenna 83. ECE Board Exam March 1996 The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the same bandwidth. A. Reference audio output B. None of these C. Audio frequency response D. Residual noise level 84. ECE Board Exam March 1996 The ___________ filter attenuates signals but passes frequencies below and above that band. A. low pass B. band pass C. band stop D. high pass 85. ECE Board Exam March 1996 In a telephone system, the customer’s telephone directory numbering is from 000 to 999, what is the capacity of the system? A. 1000 lines B. 100,000 lines C. 10,000 lines

D. 100 lines 86. ECE Board Exam March 1996 An absorption loss caused by valence electrons in the silica material from which fibers are manufactured. A. Modal dispersion B. Infrared absorption C. Ion resonance absorption D. Ultraviolet absorption 87. ECE Board Exam March 1996 In an FM receiver, which circuit removes amplitude variations? A. Exciter B. Mixer C. Discriminator D. Limiter 88. ECE Board Exam March 1996 A one-hop, full duplex, microwave system in a space diversity arrangement. Determine “how many receivers in all are used?” A. 8 B. 2 C. 4 D. 6 89. ECE Board Exam March 1996 The frequency spectrum of the stereophonic FM signal. A. 67 kHz B. 59.5 to 74.5 kHz C. 19 to 38 kHz D. 30 to 53 kHz 90. ECE Board Exam March 1996 Termination means A. result of disconnecting a line from a transmitter B. result of cutting both ends of a conductor C. looking back impedance of a line with no load D. load connected to the output end of a transmission line 91. ECE Board Exam March 1996 Asynchronous protocol is A. message oriented B. clock oriented C. bit oriented D. character oriented 92. ECE Board Exam March 1996

Transmission lines are either balanced or unbalanced with respect to _________. A. negative terminal B. input C. ground D. positive terminal 93. ECE Board Exam March 1996 What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial cable such as RG 8, 11, 58 and 59? A. 2.70 B. 0.10 C. 0.66 D. 0.30 94. ECE Board Exam March 1996 Gain of an isotropic antenna A. -1 dB B. 1 dB C. 0 dB D. 2 dB 95. ECE Board Exam March 1996 In measuring noise in a voice channel at a 4 dB test point level, the meter reads -70 dBm (F1A weighted), convert the reading to pWp. A. 53 B. 93 C. 63 D. 83 96. ECE Board Exam March 1996 Power is always __________. A. a definite amount of energy B. all of these C. the rate at which energy is used D. expressed in watts 97. ECE Board Exam March 1996 Radio fading resulting from obstruction losses. A. Log normal fading B. None of these C. Multi-path fading D. Rayleigh fading 98. ECE Board Exam March 1996 After the IF stages have been aligned, the next stage to align in FM receiver is. A. local oscillator

B. limiter stage C. RF amplifier D. mixer stage 99. ECE Board Exam March 1996 ___________ is a device in data transmission to interface data terminal equipment to an analogue transmission line. A. RS 232 B. Connector C. Modem D. RJ-11 plug 100. ECE Board Exam March 1996 What is the primary advantage of DSBSC in AM? A. Reduce bandwidth over standard AM B. All of these C. It is simpler to transmit and receive than the standard AM D. No transmitter power is wasted in the carrier

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ECE Board Exam November 1996 Which frequency band is the standard AM radio broadcast? A. HF B. UHF C. MF D. VHF ECE Board Exam November 1996 A system that performs parallel-to-serial and serial-to-parallel conversion of data link. A. DCE B. DTE C. Modem D. PC ECE Board Exam November 1996 The line control unit (LCU) operates on the data digital form. A. Data communications equipment (DCE) B. UART C. Modem D. Data terminal equipment (DTE) ECE Board Exam November 1996 Quantization noise is caused by A. binary coding techniques B. serial transmission errors C. the synchronization between encoder and decoder D. the approximation of the quantized signal ECE Board Exam November 1996 Speaker is a device that __________. A. convert current variations into sound waves B. none of these C. convert electrical energy to mechanical energy D. convert sound waves into current and voltage ECE Board Exam November 1996 An object farther from a converging lens than its focal point always has an _______ image. A. virtual B. the same in size C. inverted D. smaller size ECE Board Exam November 1996 The loss in signal power as light travels down a fiber is

A. attenuation B. propagation C. absorption D. scattering 8. ECE Board Exam November 1996 Energy that has neither been radiated into space nor completely transmitted. A. Captured waves B. Incident waves C. Standing waves D. Modulated waves 9. ECE Board Exam November 1996 One of the reasons why FDM is being replaced by TDM is A. noise is amplified with voice when an FDM system is used B. it is difficult to place channels side by side C. there is more time than frequency D. Most available frequencies has been used 10. ECE Board Exam November 1996 Which determines the number of sideband components of FM? A. Modulation frequency B. Modulation index C. Carrier frequency D. All of these 11. ECE Board Exam November 1996 How would one squeeze more channels of communication into TDM frames of standard length? A. Shorten the time delay for each channel B. Raise the amplitude C. Add modulators D. Remove the synchronizing pulses 12. ECE Board Exam November 1996 When one stations is designated as master and rest of the stations are considered slaves message handling is ________. A. polling B. WAN C. LAN D. OSI 13. ECE Board Exam November 1996 How many satellite orbital slots are requested by the Philippine government from ITU? A. 2 B. 6

C. 5 D. 3 14. ECE Board Exam November 1996 The output of a balanced modulator is ____________. A. LSB and USB B. LSB C. USB D. Carrier 15. ECE Board Exam November 1996 RS-232, RS-449, RS-530, V, 24 and X.21 are examples of ____________. A. standards for interfaces between modems and transmission facilities B. standards for various types of transmission channels C. standards for interfaces between terminals and modems D. standards for end to end performance of data communications system 16. ECE Board Exam November 1996 A special service circuit connecting two private branch exchanges (PBX). A. Phantom line B. Private line C. Tie trunk D. Tandem trunk 17. ECE Board Exam November 1996 What is the baseband frequency of standard FDM basic supergroup? A. 312 to 552 kHz B. 300 to 600 kHz C. 60 to 2540 kHz D. 60 to 108 kHz 18. ECE Board Exam November 1996 What is the data rate of the ISDN Basic access B channel? A. 192 kbps B. 32 kbps C. 64 kbps D. 144 kbps 19. ECE Board Exam November 1996 Which tester is used to measure SWR? A. Spectrum analyzer B. Multimeter C. Reflectometer D. Oscilloscope 20. ECE Board Exam November 1996 What is the transmission rate of a GSM cellular system?

A. 64 kbps B. 240 kbps C. 128 kbps D. 270 kbps 21. ECE Board Exam November 1996 A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 kW. What is the gain in dB obtain by the use of the reflector ? ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6 22. ECE Board Exam November 1996 Pulse carrier at the ratio of 8000 pulse/sec is amplitude modulated by an analog signal this type of modulation is A. PAM B. ADM C. DM D. PCM 23. ECE Board Exam November 1996 What is the applied power if a thermal RF wattmeter is connected to a transmitter through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is used. A. 4.656 watts B. 2.656 watts C. 3.656 watts D. 2.856 watts 24. ECE Board Exam November 1996 Collects very weak signal from a broadcast satellite A. Satellite dish B. LNB C. Yagi-Uda antenna D. Satellite receiver 25. ECE Board Exam November 1996 A seven-bit character can represent one of _________ possibilities. A. 14 B. 64 C. 128 D. 7 26. ECE Board Exam November 1996

The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila is A. 10 kW B. 20 kW C. 15 kW D. 5 kW 27. ECE Board Exam November 1996 A loudspeaker cabinet has an internal volume of 5,184 in3 (84,950 cm3). It has a port area on the baffle of 50 in2 (322.58cm2) and a thickness of 0.70 in (18 mm). What is the Helmholtz resonance, in hertz, of this loudspeaker enclosure? A. 250 Hz B. 245 Hz C. 240 Hz D. 255 Hz 28. ECE Board Exam November 1996 When the clearance above the obstruction is equal to the radii of even Fresnel zone at the point of reflection the RSL A. remains the same B. is above threshold C. is decreased D. is increased 29. ECE Board Exam November 1996 Digital transmission provides a higher level of signal quality than analog transmission because A. repeaters regenerate digital pulses and remove distorstion B. digital signals are easier to sample than analog signals C. digital signals are smaller than analog signals and cannot easily be distorted D. analog signals are continuous and not easily distorted. 30. ECE Board Exam November 1996 A _________ interconnects LAN having identical protocols at the physical and data link layers. A. All of these B. bridge C. router D. Gateway 31. ECE Board Exam November 1996 Both frequency and phase modulation utilize ________ modulation A. Phase B. AM and FM C. Digital

D. Angle 32. ECE Board Exam November 1996 The different angles of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitter is known as ________. A. refraction B. sensor C. mode D. emitter 33. ECE Board Exam November 1996 An invitation from the primary to a secondary to transmit a message. A. Retransmission B. Selection C. Reuse D. Polling 34. ECE Board Exam November 1996 An agency of the United Nations that formulates standards and recommend practices for all civil aviation A. ICAO B. CAA C. IATA D. ATO 35. ECE Board Exam November 1996 The transformer signal coding method for T1 carrier is A. Binary B. NRZ C. Manchester D. Bipolar 36. ECE Board Exam November 1996 When the value of k increases, the effective result is ______ of the equivalent curvatures. A. downward curvatures B. flattening C. bulging D. sharp curvature 37. ECE Board Exam November 1996 An electromagnetic wave consists of A. a magnetic field only B. both electric and magnetic fields C. an electric field only D. non-magnetic field only 38. ECE Board Exam November 1996

In a transmission line, if the maximum current to minimum current ratio is 2:1 what is the ratio of the maximum voltage to minimum voltage? A. 4:1 B. 1:2 C. 1:4 D. 2:1 39. ECE Board Exam November 1996 Satellite signal transmitted from a satellite transponder to earth’s station. A. Vertically polarized B. Uplink C. Downlink D. RHCP 40. ECE Board Exam November 1996 Multiplexing scheme use by baseband transmission. A. FDM B. Space multiplexing C. TDM D. Statistical multiplexing 41. ECE Board Exam November 1996 Which stands for dB relative level? A. dBrn B. dBm C. dBr D. dBa 42. ECE Board Exam November 1996 What is the maximum color TV bandwidth? A. 1.6 MHz B. 0.5 MHz C. 1.0 MHz D. 1.3 MHz 43. ECE Board Exam November 1996 If Ns=250, determine the earth radius k-factor. A. 1.98 B. 1.23 C. 1.33 D. 1.29 44. ECE Board Exam November 1996 Digital modulation technique used in modems. A. ASK B. PSK

C. FSK D. All of these 45. ECE Board Exam November 1996 Which of the following is not a baseband signal modulation? A. RF carrier B. Video System C. Audio signal D. Binary coded pulses 46. ECE Board Exam November 1996 The standing wave ratio is equal to ________ if the load is properly matched with the transmission line. A. 1 B. 50 C. 10 D. 2 47. ECE Board Exam November 1996 Noise from random acoustic or electric noise that has equal per cycle over a specified total frequency band. A. Thermal noise B. White noise C. Gaussian noise D. All of these 48. ECE Board Exam November 1996 When was the UHF channel (14-83) of television were added? A. 1852 B. 1904 C. 1947 D. 1952 49. ECE Board Exam November 1996 Multiplexing in a time division multiplexer occurs based upon A. the position of a frame within the group of frames B. the positioning of data within a frame C. the priority assigned to a connected device D. the activity of a connected device 50. ECE Board Exam November 1996 Ethernet is baseband system using CSMA/CD operating at A. 20 Mbps B. 10 Mbps C. 30 Mbps D. 40 Mbps

51. ECE Board Exam November 1996 A microwave communications system space loss calculation formula is A. 92.4 + 10 log f +20 log d B. 94.2 + 10 log f +20 log d C. 92.4 + 20 log f +20 log d D. 94.2 + 20 log f +20 log d 52. ECE Board Exam November 1996 Which is the non-resonant antenna? A. Broadside Antenna B. Folded Dipole C. Rhombic antenna D. End fire array 53. ECE Board Exam November 1996 The first commercial satellite A. Explorer B. Sputnik C. Telstar D. Early bird 54. ECE Board Exam November 1996 A quadrature signaling have ________ possible states. A. 16 B. 8 C. 32 D. 4 55. ECE Board Exam November 1996 Proposed the use of a clad glass fiber as a dielectric waveguide. A. Kao and Keck B. Karpon and Keck C. Karpon and Bockham D. Bockham and Kao 56. ECE Board Exam November 1996 What band does VSAT first operate? A. X-band B. C-band C. Ku-band D. L-band 57. ECE Board Exam November 1996 What is the method of diversity reception where the signal is transmitted on 2 different frequencies over the same path? A. Quadruple

B. Frequency C. Polarization D. Space 58. ECE Board Exam November 1996 The wavelength of light has no role in A. Diffraction B. Interference C. Resolving power D. Polarization 59. ECE Board Exam November 1996 Which of the following filters block FM radio band for TV channels (2 to 13)? A. High-pass filter B. Band reject filter C. Low-pass filter D. Band-pass filter 60. ECE Board Exam November 1996 The standard ASCII A. is version II of ASC B. is used only in US and Canada C. has 132 characters including 32 control characters D. is subset of 8-bit EBCDIC code 61. ECE Board Exam November 1996 Luminous efficiency is least for a A. mercury vapor lamp B. low-wattage light bulb C. high-wattage light bulb D. fluorescent tube 62. ECE Board Exam November 1996 Transmission lines when connected to antenna have A. capacitive load B. resistive load whose resistance is less than characteristics impedance C. resistive load at the resonant frequency D. resistive load whose resistance is greater than the characteristic impedance of the line 63. ECE Board Exam November 1996 What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz? A. 145.6 dB B. 138.5 dB C. 135.5 dB D. 140.89 dB

64. ECE Board Exam November 1996 What is the equivalent output of a circuit in dBm, if it is has an output of 10 watts? A. 10 dBm B. 30 dBm C. 20 dBm D. 40 dBm 65. ECE Board Exam November 1996 Satellite engine use A. liquid fuel B. jet propulsion C. ion propulsion system D. solar jet 66. ECE Board Exam November 1996 Low-power radar uses A. RIMPATT B. TRAPATT C. Magnetron D. IMPATT 67. ECE Board Exam November 1996 Transmission line must be matched to the load to A. transfer maximum voltage to the load B. transfer maximum current to the load C. reduce the load current D. transfer maximum power to the load 68. ECE Board Exam November 1996 Electromagnetic wave travel at __________ in free space. A. 300,000 km/sec B. 100,000 km/ sec C. 400,000 km/sec D. 200km/sec 69. ECE Board Exam November 1996 When electromagnetic wave are propagated through a waveguide, they A. are reflected from the walls but do not travel along them B. travel along all four walls of the waveguide C. travel along the broader walls of the guide D. travel through the dielectric without touching the walls 70. ECE Board Exam November 1996 Codes must be A. agreed upon in advance between sender and receiver B. eight bit per character

C. the same in all modern computer D. either seven or eighth bits per character 71. ECE Board Exam November 1996 Combination of modulator, channel and detector. A. Transceiver B. Discrete channel C. T/R channel D. Transponder 72. ECE Board Exam November 1996 What is the stage of the sand becoming silicon? A. Hot B. Gas C. Liquid D. Molten 73. ECE Board Exam November 1996 Noise reduction system used for film sound in movie A. dBx B. dolby C. dBa D. dBm 74. ECE Board Exam November 1996 What is the principal difference between asynchronous and synchronous transmission? A. The clocking is mixed with the data in synchronous transmission B. The pulse height are difficult C. The clocking is derived from the data in synchronous D. The bandwidth required is difficult. 75. ECE Board Exam November 1996 You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading in dBmCO. A. 16 B. 18 C. 22 D. 12 76. ECE Board Exam November 1996 What is the type of emission use by standard AM radio broadcast? A. A0 B. F3 C. A3 D. A5C 77. ECE Board Exam November 1996

____________ is the average rate of transmission of sound energy in a given direction through a cross sectional area of 1 sq.m. at right angle to the direction. A. Sound pressure B. Sound intensity C. Pressure variation D. Loudness 78. ECE Board Exam November 1996 Top loading is used in an antenna in order to increase its ___________. A. input capacitance B. beamwidth C. bandwidth D. effective height 79. ECE Board Exam November 1996 What component in the telephone set has the primary function of interfacing the handset to the local loop? A. Varistor B. Induction coil C. Resistor D. Capacitor 80. ECE Board Exam November 1996 The first passive satellite transponder. A. Early bird B. Score C. Moon D. Sputnik 81. ECE Board Exam November 1996 The primary purpose of the data modem is to A. interface analog terminal equipment to analog communications channel B. interface digital terminal equipment to analog communications channel C. interface analog terminal equipment to digital communications channel D. interface digital terminal equipment to digital communications channel 82. ECE Board Exam November 1996 ____________ is the out-of-band signaling between toll central offices (Bell System Standard) A. 2,000 Hz B. 800 Hz C. 3,835 Hz D. 3700 Hz 83. ECE Board Exam November 1996 Which symbol indicates that only one sideband is transmitted?

A. A3E B. B8E C. C3F D. H3E 84. ECE Board Exam November 1996 A voice-grade circuit using the PTN has an ideal passband of A. 0 to 4 Hz B. 0 to 4 kHz C. 0 to 4 GHz D. 0 to 4 MHz 85. ECE Board Exam November 1996 1 micron is equal to ___________ meter(s). A. 10-6m B. 10-3 m C. 106 m D. 109 m 86. ECE Board Exam November 1996 The lowest resistance grounding on earth A. Sand B. Clay C. Surface loam soil D. Limestone 87. ECE Board Exam November 1996 Troposheric scatter uses the frequencies in the ________ band. A. VLF B. UHF C. VHF D. UF 88. ECE Board Exam November 1996 The unit of pitch A. Decibel B. Phon C. Mel D. Sone 89. ECE Board Exam November 1996 What kind of receiver is used in converntional telephone handset? A. Capacitor B. Carbon C. Electromagnetic D. Ceramic

90. ECE Board Exam November 1996 Basic speed rate of digital system. A. 144 kbps B. 1,544 kbps C. 64 kbps D. 2,048 kbps 91. ECE Board Exam November 1996 A horizontal antenna is A. centrally polarized B. vertically polarized C. horizontally polarized D. perpendicularly polarized 92. ECE Board Exam November 1996 What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? A. 0.108 cm B. 1.082 cm C. 0.017 cm D. 0.0465 cm 93. ECE Board Exam November 1996 If a fiber optic system has a rise time of 16 ns, the source rise time is 1.5 ns and the detector rise time is 2 ns, what is the cable rise time? A. 14 ns B. 6 ns C. 9 ns D. 12.5 ns 94. ECE Board Exam November 1996 What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? A. 1.25 µsec B. 52 µsec C. 83.33 µsec D. 26 µsec 95. ECE Board Exam November 1996 What is the power loss of a telephone hybrid? A. 6 dB B. 2 dB C. 3 dB D. 1 dB 96. ECE Board Exam November 1996

You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc? A. 20 B. 32 C. 35 D. 25 97. ECE Board Exam November 1996 Space diversity transmission means transmitting and receiving on A. two or more antennas operating on two different frequencies B. two or more identical frequencies C. two or more different frequencies D. two or more antennas operating on the same frequencies 98. ECE Board Exam November 1996 Rules governing the transmission of digital information. A. Line protocol B. Isochronous C. Data communications D. Digital communications 99. ECE Board Exam November 1996 A digital identification associated with a cellular system A. SAT B. ESN C. MIN D. SIM 100. ECE Board Exam November 1996 ____________ is measuring the propagated field strength over the projected service area A. Radio sounding B. None of these C. Radio monitoring D. Radio survey

Test Yourself – Exam 03

1.

ECE Board Exam April 1997 What is the impedance of a balance 4-wire with a diameter of 0.25 cm and spaced 2.5 cm apart using an insulator with a dielectric constant of 2.56? A. 100Ω B. 65Ω C. 75 Ω D. 50 Ω

2.

ECE Board Exam April 1997 What is the impedance in ohms of a transformer marked for 25V, 4W, when the secondary is correctly loaded? A. B. C. D.

3.

150 Ω 156 Ω 160 Ω 165 Ω

ECE Board Exam April 1997 A single conductor running from the transmitter to the antenna. A. B. C. D.

4.

RG-8/U Single line wire Twin-lead MIcrostrip

ECE Board Exam April 1997 If voltage change equal to twice its original value, what is its corresponding change in dB? A. B. C. D.

5.

9 dB 6dB 10 dB 3dB

ECE Board Exam April 1997 To couple a coaxial line to parallel line, it is better to use a ______.

A. B. C. D.

6.

Slotted line Quarter-wave transformer Directional Coupler Balun

ECE Board Exam April 1997 What is the characteristic impedance of a single wire with a diameter d= 0.25 mm placed at the center between grounded parallel planes separated by 1 mm apart. The wire is held by a material with a velocity factor of 0.75. A. B. C. D.

7.

85 Ω 63 Ω 50 Ω 75 Ω

ECE Board Exam April 1997 If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60 dB? A. B. C. D.

8.

3 4 5 2

ECE Board Exam April 1997 ________ sets a limit on the maximum capacity of a channel with a give noise level. A. B. C. D.

9.

Hartley theorem Shannon-Hartley theorem Nyquist theorem Shannon theorem

ECE Board Exam April 1997 Transmission sent in both directions simultaneously. A. B. C. D.

Full duplex Duplex Half duplex Simplex

10.

ECE Board Exam April 1997 Industrial noise frequency is between _________. A. B. C. D.

11.

200 to 3000 Mhz 15 to 160 Mhz 0 to 10 Khz 20 Ghz

ECE Board Exam April 1997 Reference noise temperature. A. B. C. D.

12.

70 deg F 30 deg C 290 Kelvin 25 deg C

ECE Board Exam April 1997 What is the reference frequency of CCITT psophometric noise measurement? A. B. C. D.

13.

800 Hz 1500 Hz 3400 Hz 1000 Hz

ECE Board Exam April 1997 Which does not effect noise in a channel? A. B. C. D.

14.

None of these Bandwidth Temperature Quantizing level

ECE Board Exam April 1997 The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ________. A. Distortion

B. Noise C. Attenuation D. Interference

15.

ECE Board Exam April 1997 The most common unit of noise measurement in white noise testing. A. B. C. D.

16.

dBw dBk dBm NPR

ECE Board Exam April 1997 Unit of noise power of psophometer A. B. C. D.

17.

dBa pWp dBm dBmO

ECE Board Exam April 1997 100% modulation in AM means a corresponding increase in total power by: A. B. C. D.

18.

25% 75% 100% 50%

ECE Board Exam April 1997 If the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is A. B. C. D.

A5C A3J A3H A3

19.

ECE Board Exam April 1997 What particular circuit that rids FM of noise? A. B. C. D.

20.

HPF Phase shifter Limiter LPF

ECE Board Exam April 1997 What is the advantage of PTM over PAM? A. B. C. D.

21.

All of these Low sampling rate is required Much better noise immunity Simpler to generate

ECE Board Exam April 1997 At 100% modulation, the sum fo the effective voltages in both sidebands is equal to ______% of the unmodulated carrier voltage. A. B. C. D.

22.

50 71 100 25

ECE Board Exam April 1997 A carrier signal has ______. A. B. C. D.

23.

Constant peak amplitude The information Frequency range 20-20000 Hz A varying amplitude

ECE Board Exam April 1997 Which transmit only one sideband? A. A3E B. 3AJ

C. 11BE D. H3E

24.

ECE Board Exam April 1997 The final amplifier of either FM or AM transmitter operates as A. B. C. D.

25.

Class B Class C Class A Class D

ECE Board Exam April 1997 Modulation means A. Varying of information B. Utilization of a single transmission channel to carry multiple signals C. Varying of some parameters of a carrier such as its amplitude to transmit information D. Transmit pulses in DC form on a copper wire

26.

ECE Board Exam April 1997 What is the advantage of sidetone? A. B. C. D.

27.

High transmission efficiency Results to a strengthened signal No energy dissipation Assures that the telephone is working

ECE Board Exam April 1997 The standard test tone A. B. C. D.

28.

0dB 10 dBm 0 dBm 10 dB

ECE Board Exam April 1997

One (1) Erlang is equal to ________. A. B. C. D.

29.

360 CCS 100 CCS 36 CCS 3.6 CCS

ECE Board Exam April 1997 Transmission of printed material over telephone lines. A. B. C. D.

30.

Video text Facsimile Encoding Xerox copy

ECE Board Exam April 1997 1-CCS is equal to? A. B. C. D.

31.

60 100 600 1

ECE Board Exam April 1997 1 Erlang is ______. A. B. C. D.

32.

1000 TU 10 TU 100TU 1 TU

ECE Board Exam April 1997 When waves bend away from straight lines of travel, it is called _________. A. B. C. D.

Refraction Reflection Rarefaction Diffraction

33.

ECE Board Exam April 1997 Highest frequency that can be used for skywave HF communications between two given points on earth. A. B. C. D.

34.

Gyro frequency Maximum usable frequency Critical frequency Virtual frequency

ECE Board Exam April 1997 Electromagnetic radiation theory was profounded by ______. A. B. C. D.

35.

Sir Edward Appleton Sir Isaac Newton James Clerk Maxwell Michael Faraday

ECE Board Exam April 1997 Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. A. B. C. D.

36.

Ducting Ionospheric scatter Microwave Troposcatter

ECE Board Exam April 1997 What is the thickest layer of the ionosphere? A. B. C. D.

37.

E F1 F2 D

ECE Board Exam April 1997 Distance traveled by a wave in the time of one cycle.

A. B. C. D.

38.

Hop Frequency Wavelength Crest

ECE Board Exam April 1997 Which region of the ionosphere is mainly responsible for long distance night time communication? A. B. C. D.

39.

A layer D layer E layer F layer

ECE Board Exam April 1997 What is the effective earth’s radius when N=300? A. B. C. D.

40.

8500 km 6370 km 7270 km 7950 km

ECE Board Exam April 1997 The polarization of a discone antenna is _____. A. B. C. D.

41.

Horizontal Vertical Omni Directional

ECE Board Exam April 1997 _______ is the horizontal pointing angle of an antenna. A. B. C. D.

Right angle Angle of elevation Bandwidth Azimuth

42.

ECE Board Exam April 1997 Which is properly terminated antenna? A. B. C. D.

43.

Rhombic Hertz Marconi Dipole

ECE Board Exam April 1997 ______ is a device that detects both vertically and horizontally polarized signals simultaneously. A. B. C. D.

44.

Crystal Orthomode transducer Light transducer Optoisolator

ECE Board Exam April 1997 How much does the radiated power of an antenna increases if its current increased by 3.3 times? A. B. C. D.

45.

6.6 times 3.3 times 10.89 times 9.9 times

ECE Board Exam April 1997 What do you call the energy that was not radiated into space or completely transmitted? A. B. C. D.

46.

Incident waves Captured waves Standing waves Modulated waves

ECE Board Exam April 1997 What is the estimated medium wind loading in the Philippines for antenna tower design? A. 200 kph

B. 250 kph C. 300 kph D. 100 kph

47.

ECE Board Exam April 1997 The minimum number of turns a helix antenna must have. A. B. C. D.

48.

4 5 3 6

ECE Board Exam April 1997 When testing transmitter to prevent interfering with other stations, which type of antenna must be used? A. B. C. D.

49.

Dummy antenna Hertzian antenna None of these Void antenna

ECE Board Exam April 1997 A device that radiates electromagnetic energy and or intercepts electromagnetic radation. A. B. C. D.

50.

Antenna Transmitter Transmission line Transceiver

ECE Board Exam April 1997 The frequency of operation of a dipole antenna cut to length of 3.4 m. A. B. C. D.

42.9 MHz 61.3 MHz 38.5 MHz 53.5 MHz

51.

ECE Board Exam April 1997 Full duplex transmission means A. B. C. D.

52.

One way transmission 24-hour transmission Broadcast transmission Two-way simultaneous transmission

ECE Board Exam April 1997 Transmission system for a multidrop network A. B. C. D.

53.

Taken passing Polling Switching CSMA/CD

ECE Board Exam April 1997 Synchronous modems cost more than asynchronous modem because _______. A. B. C. D.

54.

They have larger bandwidth They are larger The production volume is larger They have clock recovery circuits

ECE Board Exam April 1997 What equation defines the composition of an ISDN basic access line? A. B. C. D.

55.

B+2D B+D 2B+2D 2B+D

ECE Board Exam April 1997 Modem is referred to as ______. A. Universal asynchronous Rx/Tx B. Data communication equipment C. Universal synchronous Rx/Tx

D. Data terminal equipment

56.

ECE Board Exam April 1997 _______ character signifies the start of the test for Bisync. A. B. C. D.

57.

STX ETX SOH BCC

ECE Board Exam April 1997 What is the reason why companding is employed in PCM systems? A. B. C. D.

58.

To overcome impulse noise in PCM receivers To allow amplitude limiting in the receivers To solve quantizing noise problem To protect small signals in PCM from quantizing distortion

ECE Board Exam April 1997 What is framing? A. B. C. D.

59.

Is concerned of synchronous system Refers to parallel transmission Is concerned with the boundaries between characters Is concerned with individual bits

ECE Board Exam April 1997 The method of determining the bandwidth of any processing system is ______. A. B. C. D.

60.

Bandwidth analysis Frequency spectrum Spectral analysis Frequency analysis

ECE Board Exam April 1997 It is a protocol used to connect the other packet witching network.

A. B. C. D.

61.

X.25 X.50 X.10 X.75

ECE Board Exam April 1997 Slowest communications hardware product. A. B. C. D.

62.

Synchronous Asynchronous Ethernet Internet

ECE Board Exam April 1997 Highest theoretical frequency that can be processed at a sampling rate without aliasing. A. B. C. D.

63.

Folding frequency Resonant frequency Natural frequency Critical frequency

ECE Board Exam April 1997 Data is directly on the transmission cable. A. B. C. D.

64.

Asynchronous Synchronous Baseband Broadband

ECE Board Exam April 1997 A source code whose average word length approaches the fundamental limit set by the entropy of a discrete memoryless source. A. B. C. D.

Prefix code Huffman code Entropy code Source code

65.

ECE Board Exam April 1997 ______ sets the limit on the maximum capacity of a channel with a given noise level. A. B. C. D.

66.

Hartley theorem Shannon-hartley theorem Nyquist theorem Shannon theorem

ECE Board Exam April 1997 Gateway can interconnect LANs that have ____ protocols and formats. A. B. C. D.

67.

The same Different or the same Totally different None of these

ECE Board Exam April 1997 Steps to follow to produce PCM signal. A. B. C. D.

68.

Quantizing, sampling, and coding Sampling, quantizing, and coding Sampling, coding and quantizing Coding, quantizing and coding

ECE Board Exam April 1997 Transmission sent in both directions simultaneously. A. B. C. D.

69.

Full duplex Duplex Half duplex Simplex

ECE Board Exam April 1997 _______ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. A. Feedhorn B. Satellite dish

C. Satellite receiver D. LNB

70.

ECE Board Exam April 1997 What kind of battery panels are used in some advance satellites? A. B. C. D.

71.

Gallium Arsenide solar panel Germanium based panels Silicon based panels Gallium Phosphate solar panel

ECE Board Exam April 1997 Footprint refers to coverage area in the globe A. B. C. D.

72.

Satellite radiation polarization Satellite navigation Satellite radiation pattern Satellite coverage

ECE Board Exam April 1997 Asia Sat I covers how many countries in Asia? A. B. C. D.

73.

38 40 44 42

ECE Board Exam April 1997 Insertion loss of connector-type splices for a single-mode fiber cable. A. B. C. D.

74.

0.2 dB 0.3 dB 0.09 dB 0.38 dB

ECE Board Exam April 1997 A non-coherent light source for optical communications system.

A. B. C. D.

75.

PIN Diode ILD APD LED

ECE Board Exam April 1997 Type of fiber that has the highest modal dispersion A. B. C. D.

76.

Step-index multimode Step-index single mode Graded index mode Graded index multimode

ECE Board Exam April 1997 Fiber optic cable operates near _______ frequencies. A. B. C. D.

77.

800 THz 20 MHz 200 MHz 2 GHz

ECE Board Exam April 1997 Lifetime of ILD’s A. B. C. D.

78.

150,000 h 100,000 h 50,000 h 200,000 h

ECE Board Exam April 1997 The sound energy per unit area at right angles to the propagation direction per unit time. A. B. C. D.

Sound intensity Loudness Coherence Sound stress

79.

ECE Board Exam April 1997 _______ is the transmission of sound from one room to an adjacent room thru common walls, floors or ceilings. A. B. C. D.

80.

Reverberation Refraction Flanking transmission Reflection

ECE Board Exam April 1997 The sound power level of a jet plane flying at a height of 1 km is 160 dB. What is the maximum sound pressure level on the ground directly below the plane assuming that the aircraft radiates sound equally in all directions? A. B. C. D.

81.

59.1 dB 69.1 dB 79.1 dB 89.1 dB

ECE Board Exam April 1997 Lowest frequency produced by a musical instrument. A. B. C. D.

82.

Fundamental Midrange Period Harmonic

ECE Board Exam April 1997 Sound intensity level is ________. A. B. C. D.

83.

10 log I/I(ref) 10 log I(ref)/I 30 log I/I(ref) 20 log I/I(ref)

ECE Board Exam April 1997 Tendency of sound energy to spread.

A. B. C. D.

84.

Reflection Diffraction Rarefaction Refraction

ECE Board Exam April 1997 ______ used to measure speech volume A. B. C. D.

85.

Volume meter Audio frequency meter Volume unit meter Speech meter

ECE Board Exam April 1997 What is the local oscillator frequency range commercial AM broadcast if it is equal to 455 KHz. A. B. C. D.

86.

540 to 1600 KHz 0 to 1600 KHz 995 to 2055 KHz 0 to 455 KHz

ECE Board Exam April 1997 TV channels 2, 4 and 5 are known as ________. A. B. C. D.

87.

Mid band UHF Low band UHF High band VHF Low band VHF

ECE Board Exam April 1997 ______ is the first component of any MATV system to received broadcast signals. A. B. C. D.

Receiver Antenna Filter Transmitter

88.

ECE Board Exam April 1997 Mechanism or device which enables the TV camera to move in internal and tilting motion. A. B. C. D.

89.

Tilting Scanner Pan/tilt device Panning device

ECE Board Exam April 1997 The allowable deviation ratio of commercial FM broadcast. A. B. C. D.

90.

25 15 5 75

ECE Board Exam April 1997 ______ is the time duration for one horizontal trace. A. B. C. D.

91.

48µs 52 µs 62 µs 50 µs

ECE Board Exam April 1997 Which is atmospheric attenuation? A. B. C. D.

92.

Attenuation due to rain Attenuation due to other gasses Attenuation due to mist and fog Due to water vapor and oxygen

ECE Board Exam April 1997 A microwave system that requires the use of repeater. A. Intervening terrain is favorable B. Distances involved are greater C. The required reliability is met

D. All of these

93.

ECE Board Exam April 1997 What frequency does oxygen causes excessive attenuation A. B. C. D.

94.

119 GHz 183 GHz 310 GHz 60 GHz

ECE Board Exam April 1997 RADAR means A. B. C. D.

95.

Radio detection and rating Radio detection and ranging Radio distance and ranging Radio delay and ranging

ECE Board Exam April 1997 A microwave link between the earth station and the down-town terminal. A. B. C. D.

96.

STL Uplink Downlink Terrestrial link

ECE Board Exam April 1997 The advantage of periscope antenna in microwave A. B. C. D.

97.

Minimize interference to and from other neighboring stations Shorten waveguide link Reduce tower height All of these

ECE Board Exam April 1997 Professional Regulations Commission was created under ______.

A. B. C. D.

98.

PD 323 PD 223 PD 232 RA 223

ECE Board Exam April 1997 The institutionalization of the continuing Professional Education (CPE) Program of the various regulated profession under the supervision of the Professional Regulation Commission. A. B. C. D.

99.

E.O. No. 266 E.O. No. 626 E.O. No. 662 P.D. 381

ECE Board Exam April 1997 The basic law providing for the regulation of radio station, communications in the Philippines and other purposes. A. B. C. D.

100.

Act. No.`3846 D.O. No. 11 D.O. No. 88 D.O. No. 5

ECE Board Exam April 1997 Listing of the date and time events, programs , equipment, test, malfunctions and corrections in communication system. A. B. C. D.

File Documentation Reporting Log


1.

ECE Board Exam April 1997 Extra-terrestrial noise is observable at frequencies from A. B. C. D.

2.

0 to 20 KHz Above 2 GHz 8 to 1.43 GHz 5 to 8 GHz

ECE Board Exam April 1997 Band of light waves, that are too short to be seen by human eye. A. B. C. D.

3.

Visible Infrared Ultraviolet Amber

ECE Board Exam April 1997 Two wires that are bent 90 degrees apart. A. B. C. D.

4.

Hertz Dipole Log-periodic Rhomic

ECE Board Exam April 1997 The first symbol in the designation of radio emission under the ITU rules to A. B. C. D.

5.

Nature of signals modulating the main carrier Type of information to be transmitted Bandwidth Type of modulation of the main carrier

ECE Board Exam April 1997 Operating method in which the transmission is made alternately in each direction of a telecommunication channel

A. B. C. D.

6.

Semi-duplex operation Duplex operation Half-duplex operation Simplex operation

ECE Board Exam April 1997 Production of radiation by a radio transmitting station A. B. C. D.

7.

Monitoring Emission Radiation Transmission

ECE Board Exam April 1997 The third symbol in the designation of radio emission under the ITU rules refers to A. B. C. D.

8.

Type of the modulation of the main carrier Bandwidth Nature of the signals modulating the main carrier Type of information to be transmitted

ECE Board Exam April 1997 A form of telecommunication for the transmission of transient images of fixed or moving objects. A. B. C. D.

9.

E-mail Television Radio Internet

ECE Board Exam April 1997 Radiation pattern of a discone. A. B. C. D.

Unidirectional Bidirectional Omnidirectional Figure of eight

10.

ECE Board Exam April 1997 Another SEG function that allows a person to be superimposed on another scene. A. B. C. D.

11.

Visual effect Wiper Chroma keying Special effect generation

ECE Board Exam April 1997 What signal-to-noise ratio is required for satisfactory telephone services? A. B. C. D.

12.

50 dB 30 dB 40dB 20 dB

ECE Board Exam April 1997 The use of telecommunication for automatic indicating or recording measurement at the distance from the measuring instrument. A. B. C. D.

13.

Monitoring Tracking Telemetry Telecommand

ECE Board Exam April 1997 The standard deviation of the variation in the transmission loss of a circuit should not exceed A. B. C. D.

14.

3 dB 1 dB 5 dB 0.5dB

ECE Board Exam April 1997 Noise caused by the thermal agitation of electrons in resistance. A. All of these B. Thermal noise

C. Johnson’s noise D. White noise

15.

ECE Board Exam April 1997 Unity gain antenna A. B. C. D.

16.

Isotropic Rhombic Half-wave dipole Dummy

ECE Board Exam April 1997 The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples. A. B. C. D.

17.

PFM PWM PDM PAM

ECE Board Exam April 1997 This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. A. B. C. D.

18.

Troposcatter Ionospheric scatter Ducting Microwave

ECE Board Exam April 1997 A region in front of a paraboloid antenna. A. B. C. D.

Transmission zone All of these Fraunhofer Fresnel

19.

ECE Board Exam April 1997 Designates the sensation of low or high in the sense of the base and treble. A. B. C. D.

20.

Frequency Intensity Pitch SPL

ECE Board Exam April 1997 A good example of a pilot tone system used in commercial frequency modulation stations. A. B. C. D.

21.

FDM Time division Stereo multiplexing Frequency modulation

ECE Board Exam April 1997 Emission on a frequency or frequencies immediately outside the necessary bandwidth which result from the modulation process except spurious emission. A. B. C. D.

22.

Radiation Noise Out of the band Interference

ECE Board Exam April 1997 A helical antenna is used for satellite tracking because of ______. A. B. C. D.

23.

Broad bandwidth Good front-to-back Maneuverability Circular polarization

ECE Board Exam April 1997 Background noise is the same as the following except A. Impulse noise B. White noise

C. Thermal noise D. Gaussian noise

24.

ECE Board Exam April 1997 Electronic equipment used to measure standing wave ration. A. B. C. D.

25.

Reflectometer Wavemeter Altimeter Multimeter

ECE Board Exam April 1997 A single sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation. A. B. C. D.

26.

Reduce carrier single sideband emission Half carrier single sideband emission Full carrier single sideband emission Standard single sideband emission

ECE Board Exam April 1997 Station in the mobile service not intended to be used while in motion. A. B. C. D.

27.

Coast station Fixed station Base station Land station

ECE Board Exam April 1997 The electric field lines in a plane perpendicular to the earth’s surface. A. B. C. D.

28.

Elliptical polarization Circular polarization Horizontal polarization Vertical polarization


Known to be the first satellite capable to receive and transmit simultaneously. A. B. C. D.

29.

Score Syncom I Telstar 1 Echo1

ECE Board Exam April 1997 A digital carrier facility used to transmit a DSI-formatted signal at 1.544. Mbps. A. B. C. D.

30.

T2 T1 T4 T3

ECE Board Exam April 1997 12 voice channels are sampled at 8000 sampling rate and encoded into 8 bit PCM word. Determine the rate of the data stream. a. b. c. d.

31.

354 kbps 750 kbps 768 kbps 640 kbps

ECE Board Exam April 1997 The most common device used as a light detector in fiber optic communications system. A. B. C. D.

32.

LED Darlington phototransistor APDs PIN diode

ECE Board Exam April 1997 Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in parallel. A. 0.4782µV B. 4278 µV C. 4.78 µV

D. 47.8 µV

33.

ECE Board Exam April 1997 Calculate the energy of the photon of infrared light energy at 1.55µm A. B. C. D.

34.

1.28x10-19 J 1.6 x10-19 J 1.22 x10-16 J 1.9 x10-14 J

ECE Board Exam April 1997 If a fiber optic system has a rise time of 38.55 ns, the source rise time is 12 ns and the detector rise time is 12 ns, what is the cable rise time? A. B. C. D.

35.

34.61 ns 14.55 ns 52.55 ns 26.25 ns

ECE Board Exam April 1997 Nominal voice channel A. B. C. D.

36.

20 to 20 KHz 16 to 16 KHz 3 to 3 KHz 4 KHz

ECE Board Exam April 1997 Two or more antennas separated by 9 wavelengths are used. A. B. C. D.

37.

Hybrid diversity Space diversity Polarized diversity Frequency diversity

ECE Board Exam April 1997 Nif stands for

A. B. C. D.

38.

Narrow intermediate frequency Noise interference figure Noise improvement factor Non-intrinsic fugure

ECE Board Exam April 1997 Any small element of space in the path of a wave may be considered as a source of secondary wavelet. A. B. C. D.

39.

De Morgan’s Principle Faraday’s Law Huygen’s Principle Fresnel’s Law of optics

ECE Board Exam April 1997 Modulation in which the modulated wave is always present. A. B. C. D.

40.

Carrier modulation Front-end Continuous modulation Log-periodic modulation

ECE Board Exam April 1997 Atmospheric noise is less at severe frequencies above A. B. C. D.

41.

Audio level 30 MHz 10 GHz 1 GHz

ECE Board Exam April 1997 At height about 180 km above the earth exist only during daylight. A. B. C. D.

F2 layer D layer E layer F1 layer

42.

ECE Board Exam April 1997 Radiation characteristics of a dipole A. B. C. D.

43.

Figure of eight Omnidirectional Bidirectional Unidirectional

ECE Board Exam April 1997 Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz. A. B. C. D.

44.

30 dB 11.2 dB 15.5 dB 28.17 dB

ECE Board Exam April 1997 An electromagnetic wave is ________ polarized when the electric field lies wholly in one plane containing the direction of propagation. A. B. C. D.

45.

Horizontally Linearly Circularly Vertically

ECE Board Exam April 1997 A device that reduces the intensity of light in fiber optics communication systems. A. B. C. D.

46.

Reducer Quality factor Optical attenuator Compressor

ECE Board Exam April 1997 Propagation mode of microwave in a waveguide is known as _______. A. TM B. TE

C. SW D. TEM

47.

ECE Board Exam April 1997 The width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under a specified condition and class of emission. A. B. C. D.

48.

Occupied bandwidth Reference frequency Necessary bandwidth Frequency tolerance bandwidth

ECE Board Exam April 1997 A convenient method of determining antenna impedance. A. B. C. D.

49.

Stub matching Reactance circle Smith chart Trial and error

ECE Board Exam April 1997 Which of the following fall under the high frequency band of the radio spectrum? A. B. C. D.

50.

8.2345 MHz 150.50 MHz 2.4555 MHz 35.535 MHz

ECE Board Exam April 1997 The electric field lies in a plane parallel to the earth’s surface. A. B. C. D.

Elliptical polarization Horizontal polarization Vertical polarization Circular polarization

51.

ECE Board Exam April 1997 The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance. A. B. C. D.

52.

Tracking Telemetry Telecommand Space telemetry

ECE Board Exam April 1997 The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. A. B. C. D.

53.

Peak envelope power ERP Rated power Carrier power’

ECE Board Exam April 1997 The Ku-band in the satellite service A. B. C. D.

54.

14/11 GHz 30/17 GHz 8/7 GHz 6/4 GHz

ECE Board Exam April 1997 The sinusoidal carrier is pulsed so that one of the binary states is represented by a carrier while the other is represented by its absence. A. B. C. D.

55.

FSK ASK PSK QAM

ECE Board Exam April 1997 Width measured in degrees of a major lobes between end of the love at which the relative power is one half (-3dB) its value from the peak of the lobe.

A. B. C. D.

56.

Bandwidth Wavelength Radiation Beamwidth

ECE Board Exam April 1997 The most common unit of noise measurement in white noise voltage testing. A. B. C. D.

57.

NPR dBm dBW dBrn

ECE Board Exam April 1997 Any governmental office responsible in discharging the obligations undertaken in the convention of the ITU and the regulation. A. B. C. D.

58.

Administration The union Country Telecommunications office

ECE Board Exam April 1997 A large speaker having a large diameter (15 cm and above) A. B. C. D.

59.

Coaxial speaker Woofer Tweeter Trixial speaker

ECE Board Exam April 1997 Coaxial lines are used on those systems operating _______. A. B. C. D.

Below 2 GHz At 300 MHz Above 10KHz Above 10GHz

60.

ECE Board Exam April 1997 Determine the dynamic range for a 10 bit sign magnitude code. A. B. C. D.

61.

1023 425 511 756

ECE Board Exam April 1997 A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20 Mbps with a carrier to noise ratio C/N of 8.8dB. Find Eb/No. A. B. C. D.

62.

73 dB 62.4 dB 81.8 dB 8.8 dB

ECE Board Exam April 1997 Receives and collects satellite signals form a broadcast satellite. A. B. C. D.

63.

LNB Yagi-Uda array Satellite receiver Satellite disk

ECE Board Exam April 1997 What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. B. C. D.

64.

Interference to adjacent channel Higher fidelity Increase noise Higher audio signal

ECE Board Exam April 1997 Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation. A. Peak envelop power

B. Rated power C. Carrier power D. Mean power

65.

ECE Board Exam April 1997 A method of expressing the amplitude of complex non-periodic signals such as speech. A. B. C. D.

66.

Frequency Wavelength Volume Pitch

ECE Board Exam April 1997 A government regulation in telecommunication which provide policy to improve the provision of local exchange carrier service. A. B. C. D.

67.

E.O. 109 Act 3846 E.O. 59 E.O. 546

ECE Board Exam April 1997 Radio communication operation service between mobile and land stations or between mobile stations. A. B. C. D.

68.

Land mobile satellite service Maritime mobile service Mobile service Land mobile

ECE Board Exam April 1997 The smaller the f rating, the _____ light that lens can take in. A. B. C. D.

More Intense Less Same

69.

ECE Board Exam April 1997 A radio communications service use in radio regulation between specified fixed points provided primarily for the safety of air navigation and for the regular efficient and economical air transport. A. B. C. D.

70.

Space operation service Space service Aeronautical mobile service Aeronautical fixed service

ECE Board Exam April 1997 Harmonic suppressor connected to an antenna. A. B. C. D.

71.

High pass filter Low pass filter Tank circuit M-derived filter

ECE Board Exam April 1997 The tendency of the sound energy to spread. A. B. C. D.

72.

Rarefaction Reflection Refraction Diffraction

ECE Board Exam April 1997 An earth satellite whose period of revolution is equal to the period of rotation of the earth about its axis. A. B. C. D.

73.

Geosynchronous Steerable Passive Active

ECE Board Exam April 1997 A figure of merit used to measure the performance of a radiation detector.

A. B. C. D.

74.

Noise equivalent power Ripple factor Safe factor Quality factor

ECE Board Exam April 1997 Radio wave concentration in the direction of the signal emitted by a directional antenna. A. B. C. D.

75.

Back lobe radiation Side lobe radiation Major lobe radiation Transmitted signal

ECE Board Exam April 1997 What is the channel bandwidth of a standard analogue telephone system? A. B. C. D.

76.

300-500 Hz 1200 kHz 100-300 Hz 300-3400 Hz

ECE Board Exam April 1997 A satellite receives an uplink frequency of _______ MHz from a ground station of 3700 MHz. A. B. C. D.

77.

8150 MHz 1475 MHz 2225 MHz 5925 MHz

ECE Board Exam April 1997 The outer conductor of a coaxial transmission line is always grounded at the A. B. C. D.

Input only Input and output Output only Point of high SWR

78.

ECE Board Exam April 1997 Sound intensity is given as A. B. C. D.

79.

df/dP dE/dp dA/dP dP/dA

ECE Board Exam April 1997 The lowest frequency produced by an instrument. A. B. C. D.

80.

Harmonic Fundamental Midrange 0 Hz

ECE Board Exam April 1997 The reflector and director of an antenna array are considered as A. B. C. D.

81.

Parasitic elements Transcendental elements Feed-points Driven elements

ECE Board Exam April 1997 The core of the optical fiber has ______. A. B. C. D.

82.

A medium index of refraction A lower index of refraction than the cladding A lower index of refraction than air A higher index of refraction than the cladding

ECE Board Exam April 1997 What makes an antenna physically long but electrically short? A. Top loading B. Adding C in series C. Adding L in series

D. All of these

83.

ECE Board Exam April 1997 An AM transmitter is rated 100W at 100% modulation. How much power required for the carrier? A. B. C. D.

84.

33.33 W 66.66 W 83.33 W 100 W

ECE Board Exam April 1997 Used for time division multiplexing. A. B. C. D.

85.

Frequency modulation Pulsed modulation SSB Amplitude modulation

ECE Board Exam April 1997 A means of beyond the line-of-sight propagation of microwave signal. A. B. C. D.

86.

Space wave Microwave link Troposcatter Point-to-point

ECE Board Exam April 1997 Which of the following refers to the smallest beam of satellite antenna’s radiation pattern? A. B. C. D.

87.

Hemispheric beam Spot beam Zone beam Global beam

ECE Board Exam April 1997 Theoretical gain of a hertzian dipole

A. B. C. D.

88.

0 dB 1.76 dB 3 dB 2.15 dB

ECE Board Exam April 1997 Satellite system or part of a satellite system, consisting of only one satellite and the operating earth station. A. B. C. D.

89.

Satellite system Satellite network Space system Multi-satellite link

ECE Board Exam April 1997 The difference between the original and reconstructed signal gives rise to A. B. C. D.

90.

S factor Quantizing noise S/N Fade margin

ECE Board Exam April 1997 An area in the memory used for temporary storage of information, on “Last in First out” basis. A. B. C. D.

91.

Core Register Flag Stack

ECE Board Exam April 1997 Refers to a land station in a maritime mobile service A. B. C. D.

Coast station Ship earth station Coast earth station Maritime station

92.

ECE Board Exam April 1997 Modulation in which no signal is present between pulses A. B. C. D.

93.

Pulse modulation QAM PSK FSK

ECE Board Exam April 1997 In the designation of bandwidth and emission, what letter in the first symbol represents a double-sideband type of modulation? A. B. C. D.

94.

A B C H

ECE Board Exam April 1997 Loss due to the diffraction of light when it strikes on the irregularities formed during the manufacturing process of the fiber optics. A. B. C. D.

95.

Absorption loss Attenuation Bending loss Rayleigh scattering loss

ECE Board Exam April 1997 What is the unit of electric field strength? A. B. C. D. E.

96.

Watt/meter Ohms/meter Ampere/meter Watt/meter2 No answer


Refers to the first generation of local loop system in telecommunication technology. A. B. C. D.

97.

GSM DECT Analogue cellular TACS

ECE Board Exam April 1997 An area on the surface of the earth within which the bore sight of the steerable satellite beam intended to be pointed A. B. C. D.

98.

Effective boresight area Countour boresight are Coordination boresight are Equivalent boresight area

ECE Board Exam April 1997 For a sample rate of 40 kHz, determine the maximum analog input frequency A. B. C. D.

99.

30 kHz 40 kHz 20 kHz 10 kHz

ECE Board Exam April 1997 An antenna that can only receive a television signal. A. B. C. D.

100.

Isotropic antenna TVRO Reference antenna Yagi antenna

ECE Board Exam April 1997 Halo is also called A. B. C. D.

Flare Dark current Glitch Ghost


1.

ECE Board Exam April 1998 Space diversity transmission means transmitting and receiving on _______. A. B. C. D.

2.

Two or more antennas operating on two different frequencies Two or more identical frequencies Two or more antennas operating on the same frequency Two or more different frequency

ECE Board Exam April 1998 An increase in the effective power radiated by an antenna in a certain desired direction at the expense of power radiated in other directions. A. B. C. D.

3.

Antenna gain Antenna back lobe ration Antenna total ration Antenna efficiency

ECE Board Exam April 1998 A radio land station in the land mobile service A. B. C. D.

4.

Mobile station Land station Base station Ship earth station

ECE Board Exam April 1998 A major and basic advantage for the use of a klystron. A. B. C. D.

5.

High power Efficiency Lesser noise Cheaper

ECE Board Exam April 1998 A band where most military satellite often operate

A. B. C. D.

6.

Ku C X L

ECE Board Exam April 1998 The final power amplifier in an FM transmitter usually operates class ______. A. B. C. D.

7.

AB C B A

ECE Board Exam April 1998 In television broadcasting vivid strong colors are often referred as _______. A. B. C. D.

8.

Saturation Hue Chrominance Luminance

ECE Board Exam April 1998 Where do the maximum current and minimum voltage values on a resonant Hertz dipole exist? A. B. C. D.

9.

Center of the antenna Near the end of the antenna Near the center of the antenna Ends of the antenna

ECE Board Exam April 1998 How can the antenna efficiency of an HF grounded vertical antenna be made comparable to that of a half-wave antenna? A. B. C. D.

By lengthening the vertical By installing a good ground radial system By shortening the vertical By isolating the coax shield from ground

10.

ECE Board Exam April 1998 At what distance is VHF propagation normally limited? A. B. C. D.

11.

Around 500 miles Around 1500 miles Around 2000 miles Around 1000 miles

ECE Board Exam April 1998 What is meant by the term antenna efficiency? A. B. C. D.

12.

Efficiency = effective radiated power/transmitter output x 100% Efficiency = radiation resistance/ transmission resistance Efficiency = total resistance/radiation resistance x 100% Efficiency = radiation resistance/total resistance x 100%

ECE Board Exam April 1998 This is referred to as a fixed radio station that broadcasts program material from studio to transmitter by radio link. A. B. C. D.

13.

Aural BC intercity relay Aural broadcast STL Shortwave station Remote-pickup

ECE Board Exam April 1998 What law does a light traveling in air optical fiber follow? A. B. C. D.

14.

Millman Snell’s Maxwell Huygen


Which of the following is designated as the international distress, safety and calling frequency for radio telephony for stations of the maritime mobile service when using frequencies in the authorized bands between 156 and 174 MHz? A. B. C. D.

15.

165.8 MHz 156.8 MHz 158.6 MHz 168.5 MHz

ECE Board Exam April 1998 A device that connects two dissimilar networks and performs the protocol conversion. A. B. C. D.

16.

Gateway Coupler Transformer Converter

ECE Board Exam April 1998 The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance. A. B. C. D.

17.

Tracking space command Telecommand Trunking

ECE Board Exam April 1998 Best described a dip-meter. A. B. C. D.

18.

A variable LC oscillator with metered feedback current An SWR meter A counter A field strength meter

ECE Board Exam April 1998 Refers to an emission designation for facsimile? A. J3E and F4E B. A3J and A4E

C. A3E and F3C D. R3E and A3E

19.

ECE Board Exam April 1998 How does a SSB transmitter output power normally expressed? A. B. C. D.

20.

Average power In terms of peak envelop power In terms of peak-to-peak power Peak power

ECE Board Exam April 1998 In satellite communication, the Geostationary satellites are conveniently located with respect to the equator at _______. A. B. C. D.

21.

45 degrees latitude 90 degrees latitude 0 degrees latitude 5 degrees latitude

ECE Board Exam April 1998 Known as the technique for adding a series inductor at or near the center of an antenna element in order to cancel the capacitive reactance of an antenna. A. B. C. D.

22.

Dipole Center loading Reflector loading coil

ECE Board Exam April 1998 What is meant by the term antenna bandwidth A. B. C. D.

Antenna length divided by the number of elements. The angle between the half-power radiation points The frequency range over which and antenna can be expected to perform well The angle formed between two imaginary line drawn through the ends of the elements

23.

ECE Board Exam April 1998 A multiple access technique used in GSM cellular system A. B. C. D.

24.

TACS FDMA TDMA CDMA

ECE Board Exam April 1998 Refers to an effect of selective fading. A. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station. B. A fading effect caused by small changes in beam heading at the receiving station. C. A fading effect caused by the time differences between the receiving and transmitting stations. D. A fading effect caused by large changes in the height of the ionosphere, as experienced at the receiving station.

25.

ECE Board Exam April 1998 Where the voltage node of a half-wave antenna does exists? A. B. C. D.

26.

At feed point Near the center At center Near the feed point

ECE Board Exam April 1998 This is a flexible vertical rod antenna commonly used on mobiles. A. B. C. D.

27.

Marconi Hertz Whip Ground plane

ECE Board Exam April 1998 Referred to as an average power from the radio transmitter supplied to the antenna transmission line taken during one radio frequency cycle under no modulation.

A. B. C. D.

28.

Carrier power Rated power Peak envelop power Mean power

ECE Board Exam April 1998 _______ is a major cause of the sporadic-E condition A. B. C. D.

29.

Temperature inversions Sunspots Meteors Wind shear

ECE Board Exam April 1998 Which of the following refers to a double side band full carrier? A. B. C. D.

30.

A3E A3J F3 R3A

ECE Board Exam April 1998 What is the basic qualification of an applicant for public carrier network before a certificate of public convenience or a provisional authority is issued? A. B. C. D.

31.

Franchise SEC document Business permit Radio station license

ECE Board Exam April 1998 How wide is the spectrum bandwidth of a single GSM carrier? A. B. C. D.

100 kHz 200 kHz 50 kHz 16 kHz

32.

ECE Board Exam April 1998 With which emission type is the capture-effect most pronounced? A. B. C. D.

33.

CW FM SSB AM

ECE Board Exam April 1998 What is a dummy antenna? A. B. C. D.

34.

One which is used as a reference for gain measurements And antenna used for hand-held radio An non-directional transmitting antenna A non-radiating load for a transmitter used for testing

ECE Board Exam April 1998 Best description of a collinear and broadside antenna radiation pattern. A. B. C. D.

35.

Bidirectional Perfect circle Unidirectional Omnidirectional

ECE Board Exam April 1998 A satellite beam that covers almost 42.4% of earths surface. A. B. C. D.

36.

Spot beam Global beam Zone beam Hemispheric beam

ECE Board Exam April 1998 The modulation technique used by GSM cellular system A. Phase shift keying B. Frequency shift keying C. Gaussian minimum shift keying

D. QAM

37.

ECE Board Exam April 1998 ________ generates light beam at a specific visible frequency. A. B. C. D.

38.

Glass fiber Infrared Light waves Laser

ECE Board Exam April 1998 The most common application of satellites A. B. C. D.

39.

Surveillance Reconnaissance Defense systems Communication

ECE Board Exam April 1998 Referred to the dielectric constant of a transmission line material. A. B. C. D.

40.

Inductance and capacitance Velocity factor Characteristic impedance Propagation velocity

ECE Board Exam April 1998 Referred to as a ferrite device that can be used in lieu of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna. A. B. C. D.

41.

Isolator Circulator Coupler Diode.


_______ is more prevalent in analog signals that have steep slopes or whose amplitudes vary rapidly. A. B. C. D.

42.

Peak limiting Quantization noise Granular noise Slope overload

ECE Board Exam April 1998 Station located on an object which is beyond and is intended to go beyond the major portion of the earth’s atmosphere. A. B. C. D.

43.

Terrestrial station Space station Satellite station Mobile satellite station

ECE Board Exam April 1998 A radio frequency in the ultra high frequency band of the radio spectrum band. A. B. C. D.

44.

235.50 MHz 450.50 MHz 150.50 GHz 0.31250 GHz

ECE Board Exam April 1998 Technical study which deals with production, transport and delivery of a quality signal from source to destination. A. B. C. D.

45.

Transmission system engineering Communication system engineering Telephony engineering Telegraphic engineering

ECE Board Exam April 1998 It is used to connect computers in the same building or in same area A. MAN B. LAN

C. SWITCH D. WAN

46.

ECE Board Exam April 1998 Referred by radio regulation as the station in the mobile service not intended to be used while in motion. A. B. C. D.

47.

Fixed station Base station Land station Coast station

ECE Board Exam April 1998 What is the mixing process? A. B. C. D.

48.

Distortion caused by auroral propagation The combination of two signals to produce sum and difference frequencies. The elimination of noise in wideband receiver by phase differentiation The elimination of noise in a wideband receiver by phase comparison

ECE Board Exam April 1998 Which of the following systems is not used in radio detection and ranging? A. B. C. D.

49.

Frequency shift Frequency modulation Pulse radar Amplitude modulation

ECE Board Exam April 1998 Considered as the main source of an internal noise. A. B. C. D.

50.

Device imperfection Thermal agitation Temperature change Flicker


In shipboard satellite dish antennas system, azimuth is referred as the _______. A. B. C. D.

51.

0 to 90 degrees Vertical aiming of the antenna North to East Horizontal aiming of the antenna

ECE Board Exam April 1998 What is the period of a wave? A. B. C. D.

52.

The number of degrees in tone cycle The number of zero crossing in one cycle The amplitude of the wave The time required to complete one cycle

ECE Board Exam April 1998 Is the total useful information processed or communicated over a specific amount of time A. B. C. D.

53.

Baud rate Bit rate Information theory Throughput

ECE Board Exam April 1998 What is the approximate percentage of earth coverage of a geostationary satellite at zero degree elevation? A. B. C. D.

54.

33.3% 45.2% 42.5% 30.5%

ECE Board Exam April 1998 This refers to an area in the memory used for temporary storage of information on the basis of “Last in First out”. A. Core B. Register C. Flag

D. Stack

55.

ECE Board Exam April 1998 What is a driven element of an antenna? A. B. C. D.

56.

Always the rearmost element Always the forwardmost element The element fed by the transmission line The element connected to the rotator

ECE Board Exam April 1998 Which of the following term best described the overload distortion? A. B. C. D.

57.

Peak limiting Quantization noise Granular noise Slope distortion

ECE Board Exam April 1998 What do you mean by the outward flow of and energy from any source in the form of radio waves? A. B. C. D.

58.

Radiation Emission Encoding Tracking

ECE Board Exam April 1998 Refer to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. A. B. C. D.

59.

Drift Flash over Frequency deviation Deviation ratio


Find the product of the following binary number 100 to 101. A. B. C. D.

60.

11000 10100 10010 11100

ECE Board Exam April 1998 Which of the following is and impedance matching ration of coax balun? A. B. C. D.

61.

2:8 1:2 4:1 2:1

ECE Board Exam April 1998 Quantity that do not change when a beam of light enters on e medium to another. A. B. C. D.

62.

Frequency Wavelength Direction Speed

ECE Board Exam April 1998 Which of the following described the very early standard that defines binary digits as space/mark line condition and voltage levels? A. B. C. D.

63.

V.4 V.2 V.1 V.5

ECE Board Exam April 1998 A form of single sideband emission where the degree of carrier suppression enable the carrier to be reconstituted and be used for demodulation. A. Half carrier single sideband emission B. Full carrier single sideband emission C. Reduced carrier single sideband emission

D. Double sideband emission

64.

ECE Board Exam April 1998 An instrument for recording waveforms of audio frequency. A. B. C. D.

65.

Oscilloscope Phonoscope Radioscope Audioscope

ECE Board Exam April 1998 How much is the required minimum power output of an international AM BC stations? A. B. C. D.

66.

5 kW 30 kW 10 kW 50 kW

ECE Board Exam April 1998 What is the equivalent of decimal 51 in binary? A. B. C. D.

67.

111011 110011 111001 100011

ECE Board Exam April 1998 One of the first satellite system catering personal based communications services scheduled for operation. A. B. C. D.

68.

Iridium system Plutonium system Indium system Gallium system

ECE Board Exam April 1998 What do you call a circuit that controls the magnetron output?

A. B. C. D.

69.

Inverter Impeller Modulator Converter

ECE Board Exam April 1998 Known as the satellite transmitted signal form a satellite transponder to earth’s station. A. B. C. D.

70.

Uplink Down link RHCP Vertically polarized

ECE Board Exam April 1998 Which of the following colors of light rays has the shortest wavelength? A. B. C. D.

71.

Yellow Violet Red Blue

ECE Board Exam April 1998 Antenna which is not properly terminated A. B. C. D.

72.

Isotropic Non-resonant Whip Resonant

ECE Board Exam April 1998 Term in communication which is referred, “to send out in all direction”. A. B. C. D.

Announce Broadcast Transmit Media

73.

ECE Board Exam April 1998 At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? A. B. C. D.

74.

Minimum voltage and minimum current Equal voltage and current Minimum voltage and maximum current Maximum voltage and minimum current.

ECE Board Exam April 1998 One of the following stands for SONET acronym in telecommunication A. B. C. D.

75.

System optical network Simple operation network Synchronous optical network System operating network

ECE Board Exam April 1998 How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator or ferrite isolator in the feed line of the transmitter and duplexer C. By using a class C final amplifier with high driving power D. By installing a low-pass filter in the antenna feed line

76.

ECE Board Exam April 1998 What propagation condition is usually indicated when a VHF signal is received from a station over 5000 miles away? A. B. C. D.

77.

Moonbounce D-layer absorption Tropospheric ducting Faraday rotation

ECE Board Exam April 1998 In radio High frequency communications the higher the radio frequency the ______.

A. B. C. D.

78.

Higher it can reach Shorter it can reach Effect is null Longer it can reach

ECE Board Exam April 1998 The signal to noise ratio that is required for a satisfactory television reception. A. B. C. D.

79.

30 dB 40 dB 10 dB 20 dB

ECE Board Exam April 1998 What is meant by referring to electromagnetic waves as horizontally polarized? A. B. C. D.

80.

The electric field is parallel to the earth Both the electric and magnetic fields are vertical Both the electric and magnetic fields are horizontal The magnetic fields is parallel to the earth

ECE Board Exam April 1998 What is emission F3F? A. B. C. D.

81.

Facsimile Modulated CW RTTY Television

ECE Board Exam April 1998 How can receiver desensitizing be reduced? A. B. C. D.

Increase the receiver bandwidth Ensure good RF shielding between the transmitter and receiver Increase the transmitter audio gain Decrease the receiver squelch, gain.

82.

ECE Board Exam April 1998 Circuit used to amplify the optical signal in fiber optics communications links. A. B. C. D.

83.

Attenuator Optical repeater Optical amplifier Generator

ECE Board Exam April 1998 What do you call the single booster installed on the antenna dish of satellite receiver? A. B. C. D.

84.

Low noise amplifier Single amplifier Noise amplifier Rectifier

ECE Board Exam April 1998 Term for the transmission of printed pictures by radio? A. B. C. D.

85.

Facsimile ACSSB Xerography Television

ECE Board Exam April 1998 An interfering current in a telegraph or signaling channel due to telegraph or signaling current by another channel. A. B. C. D.

86.

Crosstalk Noise current Crossfire Intermodulation

ECE Board Exam April 1998 Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150 MHz) marine-band receiver? A. In the ionosphere

B. In the receiver rear end C. In the receiver front end D. In the atmosphere

87.

ECE Board Exam April 1998 Known as the data transfer scheme that used handmaking principle. A. B. C. D.

88.

Synchronous data transfer scheme DMA data transfer scheme Asynchronous data transfer scheme Uninterrupted data transfer scheme

ECE Board Exam April 1998 Type of modulation used in TV broadcast visual transmitter. A. B. C. D.

89.

Pulse modulation DSBFC Vestigial sideband SSBFC

ECE Board Exam April 1998 A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 90%. A. B. C. D.

90.

5 kW 20 kW 15 kW 8.36 kW

ECE Board Exam April 1998 Best describe as an amplifier used in radio telephony. A. B. C. D.

Magnifier Class B Class C Class A

91.

ECE Board Exam April 1998 The latest government regulation in the telecommunication which provides policy for the provision of local exchange carrier service. A. B. C. D.

92.

E.O. 546 E.O. 109 Act 3948 E.O. 59

ECE Board Exam April 1998 Referred to as the stage in the radio receiver that contributes most of the noise. A. B. C. D.

93.

IF amplifier Supply stage Speaker Mixer

ECE Board Exam April 1998 The frequency tolerance of an AM radio broadcast station A. B. C. D.

94.

200 Hz 2000 Hz 20 Hz 2 Hz

ECE Board Exam April 1998 What are electromagnetic waves? A. A wave consisting of two magnetic fields at right angles to each other B. A wave consisting of an electric field and a magnetic field at right angles to each other. C. Alternating currents in the core of an electromagnet D. A wave consisting of two electric fields at right angles to each other

95.

ECE Board Exam April 1998 What is the frequency range of C-band? A. 10.95 to 14.5 GHz

B. 27.5 to 31 GHz C. 3.4 to 6.424 GHz D. 1.53 to 2.7 GHz

96.

ECE Board Exam April 1998 Determine from the following the basic mode of transmission system in the public data network in which data are transferred from the source to the network and from the network to the destination in the frame format. A. B. C. D.

97.

Voice mode Asynchronous mode Synchronous mode Packet mode

ECE Board Exam April 1998 Refers to a type of beam antenna which uses two or more straight elements arranged in line with each other. A. B. C. D.

98.

Dipole antenna Yagi antenna Whip antenna Rhombic antenna

ECE Board Exam April 1998 What is a frequency discriminator? A. B. C. D.

99.

A circuit for filtering two closely adjacent signals A circuit for detecting FM signals An FM generator An automatic bandswitching circuit.

ECE Board Exam April 1998 These are used to connect non-ISDN equipment ot ISDN line. A. B. C. D.

Digipeaters Terminal adapters Local repeaters Terminal repeaters

100.

ECE Board Exam April 1998 The executive branch of government in charge of policy making in the telecommunications. A. B. C. D.

National telecommunications commission Telecommunications control bureau Department of transportation and communications Bureau of telecommunications


1.

ECE Board Exam April 1998 When adjusting an RF filter on a transmitter using a dummy load, how much watts dissipation should it stand to test a 150 watts transmitter? A. B. C. D.

2.

75 watts 300 watts 50 watts 150 watts

ECE Board Exam April 1998 When does broadcast station conduct and equipment test? A. B. C. D.

3.

During day time During night time At any time During experimental period

ECE Board Exam April 1998 Channel 7 of the regular television channel belongs to which band? A. B. C. D.

4.

Low VHF band High VHF band Low UHF band High UHF band

ECE Board Exam April 1998 Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. B. C. D.

5.

Poor soldered connections Power supply voltage changes Loose connections in the oscillator, amplifier, or antenna circuits DC and RF heating of resistors, causing then to change values.


A third symbol radio emission which represent telephone transmission including sound broadcasting. A. B. C. D.

6.

W F C E

ECE Board Exam April 1998 Which of the following is not a common microwave application? A. B. C. D.

7.

Radar Data transmission Space communications Mobile radio

ECE Board Exam April 1998 Which of the following is referred to as a radio emission without sidebands A. B. C. D.

8.

Analog Carrier Data Voice

ECE Board Exam April 1998 Ho w many times bigger does the bandwidth of a fiber optic multimode have over a cable? A. B. C. D.

9.

50 times bigger 100 times bigger 10 times bigger 5 times bigger

ECE Board Exam April 1998 Type of antenna which is normally used for satellite tracking service. A. B. C. D.

Omni Helical Yagi Dipole

10.

ECE Board Exam April 1998 One of the following is referred to as a major component of an optical time domain reflectometer A. B. C. D.

11.

Pulse generator and vertical plate Laser and horizontal plate Pulse generator laser Vertical and horizontal plate

ECE Board Exam April 1998 One of the commonly used domain in the internet service. A. B. C. D.

12.

Yahoo http com www

ECE Board Exam April 1998 What is meant by the term radiation resistance for an antenna? A. The resistance in the trap coils to received signal B. An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna C. The specific impedance of the antenna D. Losses in the antenna elements and feed line

13.

ECE Board Exam April 1998 Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. A. B. C. D.

14.

Carrier Stray signal Back wave Loss wave


An advantage of optic fiber rejecting an induced noise signals from magnetic field or solar storms flux. A. B. C. D.

15.

Electric hazard Cross talk Immunity to noise Shielding

ECE Board Exam April 1998 What kind of effect is referred to a varying light producing a varying voltage output of a detector? A. B. C. D.

16.

Current effect Voltage effect Resistive effect Photovoltaic effect

ECE Board Exam April 1998 ______ is known to be the first satellite capable of receiving and transmitting simultaneously. A. B. C. D.

17.

Syncom I Telstar I Score Aguila

ECE Board Exam April 1998 The extremely high frequency (EHF) band is in the radio spectrum range of _______. A. B. C. D.

18.

30 to 300 kHz 30 to 300 GHz 3 to 30 MHz 3 to 30 GHz

ECE Board Exam April 1998 One of the following is not among the advantages of series modulation A. No transformer B. Suppressed white noise C. Simple

D. Modulates any frequency

19.

ECE Board Exam April 1998 What do you call the service area of a standard AM broadcast where fading is allowed but not objectionable co-channel interference? A. B. C. D.

20.

Experimental Secondary Tertiary Primary

ECE Board Exam April 1998 A third symbol emission which represent television. A. B. C. D.

21.

C D F A

ECE Board Exam April 1998 In telecommunications when we call data communications it means the transmission of________. A. B. C. D.

22.

Voice and video Voice Video Computer data

ECE Board Exam April 1998 If frequency range of 401.000MHz to 401.050MHz has to be channelized at 12.5 kHz between channel, what is the center of its first channel from the lower limit? A. B. C. D.

401.125MHz 401.00625MHz 401.025MHz 401.0125MHz

23.

ECE Board Exam April 1998 Determine the effective radiated power of 20 kW TV broadcast transmitter whose antenna has a field gain of 2. A. B. C. D.

24.

40 kW 80,000 watts 40,000 watts 8,000 watts

ECE Board Exam April 1998 In indication signal for a handshake form the DCE to the DTE in response to an active condition for the request to send a signal. A. B. C. D.

25.

Data transmission Clear to send Receive data Data set ready

ECE Board Exam April 1998 In amplitude modulation technique the unmodulated carrier is referred to as having ______. A. B. C. D.

26.

100% modulation 0% modulation 50% modulated Over modulated

ECE Board Exam April 1998 One of the following is not among the major components required on board ship under the global maritime distress and safety system. A. B. C. D.

27.

On board radio facilities Radio operator telegraphy onboard Shore base facilities Radio personnel on board

ECE Board Exam April 1998 In what form does the information of data communications is transmitted between two points?

A. B. C. D.

28.

Alphanumeric form Alphabetic form Numeric form Binary form

ECE Board Exam April 1998 Width of frequency band just enough to ensure the transmission of information at a required rate and quality required, and under a specified condition and class of emission. A. B. C. D.

29.

Occupied bandwidth Transmission bandwidth Necessary bandwidth Frequency bandwidth

ECE Board Exam April 1998 Refers to one of the front end circuit of a VHF TV superheterodyne receiver which is usually a separate circuit coupled to the mixer. A. B. C. D.

30.

Antenna feed AGC RF amplifier Local oscillator

ECE Board Exam April 1998 All bits in character are sent and received ______ in serial port. A. B. C. D.

31.

In groups of 3 bits One at a time In groups of 2 bits Simultaneously

ECE Board Exam April 1998 One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency oscillation. A. Heating and expansion of oscillator coil B. DC and RF ac heating of resistors which cause change in values C. Heating of capacitor in the oscillator

D. Loose connections in the oscillator, amplifier, or antenna circuits.

32.

ECE Board Exam April 1998 Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. B. C. D.

33.

AF amplifier Antenna Detector Crystal

ECE Board Exam April 1998 It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation, taken under the normal operating conditions. A. B. C. D.

34.

Carrier power Rated power Mean power Peak envelop power

ECE Board Exam April 1998 Determine from the following radio frequency that falls under the very high frequency band of the radio spectrum. A. B. C. D.

35.

345.00 MHz 144.50 MHz 235.50 MHz 450.00 MHz

ECE Board Exam April 1998 What is the typical number of bits in a static memory location? A. B. C. D.

1 2 16 8

36.

ECE Board Exam April 1998 What controls the contrast of a television cathode ray picture? A. B. C. D.

37.

AFC video stage gain Audio gain control CRT bias

ECE Board Exam April 1998 Determine the dB gain of a receiving antenna which delivers a microvolt signal to a transmission line over that of an antenna that delivers a 20 microvolt signal under identical circumstances. A. B. C. D.

38.

10 dB 6 dB 3 dB 8 dB

ECE Board Exam April 1998 Refers to one of a commonly used internet service domain. A. B. C. D.

39.

www http gov infoseek

ECE Board Exam April 1998 A law that specifically requires the service of a duly registered electronics and communications engineer in the designing installation and construction, operation and maintenance of radio stations. A. B. C. D.

40.

Act 3846 LOl 1000 R.A. 5734 Dept. order 88

ECE Board Exam April 1998 Which band does channel 14 of the television channel belong?

A. B. C. D.

41.

High VHF band EHF band UHF band Low VHF band

ECE Board Exam April 1998 How many ship’s area is designated in the implementation of the global maritime distress and safety system. A. B. C. D.

42.

Four Six Three Two

ECE Board Exam April 1998 What kind of receiver is used in conventional telephone handset? A. B. C. D.

43.

Capacitor Electromagnetic Carbon Ceramic

ECE Board Exam April 1998 Determine the lower half-power frequency of a class-C amplifier having upper half-power frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10. A. B. C. D.

44.

1.0025 MHz 10.525 MHz 0.5 MHz 10 MHz

ECE Board Exam April 1998 This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. A. B. C. D.

Absorption modulation Simultaneous modulation Dynamic instability Series modulation

45.

ECE Board Exam April 1998 Main basic components of a data communication are composed of the following. A. B. C. D.

46.

Computer, modern and router Computer, bridge and gateway Transmitter, channel and receiver Transmitter, computer and modem

ECE Board Exam April 1998 The international radio consultative committee is referred to in international radio communication as ______. A. B. C. D.

47.

IRCC ITU IRR CCIR

ECE Board Exam April 1998 Refers to a continuous tone generated in a local exchange terminal through a combination of two frequencies 350 Hz, and 440 Hz. A. B. C. D.

48.

Busy tone Call waiting tone Dial tone Standard tone

ECE Board Exam April 1998 One of the advantages of fiber optic which is referred to the volume of capacity of signals it can carry. A. B. C. D.

49.

Security Weight Bandwidth Physical size


Assume a frequency range of 401.000 MHz to 401.050 MHz, if you apply 25 kHz channeling plan, determine the center frequency of the first channel from the lower limit. A. B. C. D.

50.

401.010 MHz 401.0125 MHz 401.025 MHz 401.00625 MHz

50 ECE Board Exam April 1998 The stability of transmitted signal from a simple Hartley oscillator single transmitter which is coupled to and antenna wire affected by ______. A. B. C. D.

51.

Chirping of oscillator Closer coupling between the oscillator and the antenna. Location of antenna Material of antenna

ECE Board Exam April 1998 Refers to the first symbol in an emission designation with an amplitude modulated main carrier represented by letter H. A. B. C. D.

52.

Single sideband suppressed carrier Double sideband full carrier Independent sideband Double sideband

ECE Board Exam April 1998 Assume a frequency range of 405.0125 MHz to 405.0875 MHz and 25 kHz channeling plan, determine the center frequency of the second channel from the lower limit. A. B. C. D.

53.

405.030 MHz 405.025 MHz 405.050 MHz 405.075 MHz

ECE Board Exam April 1998 An entity, relying on the transmission, switching and local distribution facilities of local exchange and inter-exchange operators, and overseas carriers, offers enhanced services beyond those ordinarily provided by such carriers.

A. B. C. D.

54.

International carrier Value-added service provided Inter-exchange carrier Local exchange carrier

ECE Board Exam April 1998 Which of the following refers to full duplex transmission? A. B. C. D.

55.

One at a time transmission Two transmission medium Intermittent transmission Two way simultaneous transmission

ECE Board Exam April 1998 What is the first symbol of a radio signal transmission having an amplitude modulated signal carrier, double side band? A. B. C. D.

56.

C B H A

ECE Board Exam April 1998 Best choice of transmission line component to couple a coaxial line to a parallel-wire line A. B. C. D.

57.

Shorting Balun Slotted line Directional coupler

ECE Board Exam April 1998 Which of the following refers to the video signal amplitude that determines the quality of the picture? A. B. C. D.

Chrominance Luminance Brightness Contrast

58.

ECE Board Exam April 1998 ________ is the method of encoding audio signals used in US standard 1544 kbit/s 24 channel PCM systems. A. B. C. D.

59.

Shannon’s law A-law Newton’s law Mu-law

ECE Board Exam April 1998 In radio regulation, the first symbol in the designation of radio emission is ______. A. B. C. D.

60.

Bandwidth Nature of signal(s) modulation the main carrier Type of modulation of the main carrier Type of information to be transmitted

ECE Board Exam April 1998 Who is the principal administrator of republic act 7925? A. B. C. D.

61.

BOC DOTC Congress NTC

ECE Board Exam April 1998 What is the term for the ration of the radiation resistance of an antenna to the total resistance of the system? A. B. C. D.

62.

Effective radiated power Beamwidth Radiation conversion loss Antenna efficiency

ECE Board Exam April 1998 Where does the AM broadcast band located in the spectrum band?

A. B. C. D.

63.

HF band VHF band LF band MF band

ECE Board Exam April 1998 What determines the velocity factor in transmission line? A. B. C. D.

64.

The center conductor resistivity Dielectrics in the line The termination impedance The line length

ECE Board Exam April 1998 Refers to an address that identifies a server on the network and a particular document on the server A. B. C. D.

65.

Hypertext HTML Wide area network Uniform resource locator

ECE Board Exam April 1998 Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. A. B. C. D.

66.

Digital emission Key emission Cycle emission Spark emission

ECE Board Exam April 1998 Is a kind of satellite which has a period of revolution equivalent to the period of rotation of the earth about its axis. A. Passive satellite B. Synchronous satellite C. Active satellite

D. Geosynchronous satellite

67.

ECE Board Exam April 1998 Electromagnetic waves of frequencies arbitrarily lower than 3,000 GHz, propagated in space without artificial guide. A. B. C. D.

68.

Space waves Terrestrial waves Mobile Hertzian waves

ECE Board Exam April 1998 Frequencies above ______ kHz, are referred to as the radio frequencies. A. B. C. D.

69.

20 2 10 200

ECE Board Exam April 1998 Who is responsible in the correctness and accuracy of transmitted information content over a data communication? A. B. C. D.

70.

The channel The transmitter and receiver The modem The bridge

ECE Board Exam April 1998 What is meant by the term deviation ratio? A. The ratio of the carrier center frequency to the audio modulating frequency B. The ratio of the highest audio modulating frequency to the average audio modulating frequency C. The ratio of the maximum carrier frequency deviation to the highest audio modulation frequency D. The ratio of the audio modulating frequency to the center carrier frequency

71.

ECE Board Exam April 1998 A quarter wavelength devices made of crystalline calcite that changes polarization in the optic fiber communication. A. B. C. D.

72.

Isolator Retarder Polarizer Filters

ECE Board Exam April 1998 Known as the maritime communications law which was enacted December 5, 1927 A. B. C. D.

73.

R.A. No. 109 R.A. No. 3396 R.A. No. 7925 R.A. No. 3846

ECE Board Exam April 1998 How do you transmit through multiplexing, a thousand of voice channel information over a single fiber optic using on e wavelength? A. B. C. D.

74.

Polar division Time division Fiber division Frequency division

ECE Board Exam April 1998 In regulation of public telecommunications carrier such as in the evaluation of new entrant, the following consideration shall be given emphasis to _______. A. B. C. D.

75.

Legal, technical and citizenship Technical, citizenship and kind of service Citizenship, capacity and financial Technical, legal and financial

ECE Board Exam April 1998 One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage or

stages that develop the high power output. The purpose of which is to develop a good frequency stability. A. B. C. D.

76.

Goldsmith MOPA Alexanderson Hartley

ECE Board Exam April 1998 What is the meaning of the term velocity factor of a transmission line? A. The index of shielding for coaxial cable B. The velocity of the wave on the transmission line multiplied by the velocity of light in vacuum C. The ratio of the characteristic impedance of the line to the terminating impedance D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum

77.

ECE Board Exam April 1998 Which of the following determines the characteristics of a transmission line? A. B. C. D.

78.

Inductance Capacitance Physical dimension Length

ECE Board Exam April 1998 One of the following is among the types of fiber optics used in electronics communication. A. B. C. D.

79.

Step-index multimode Graded-index multimode Semi-graded multimode Single mode

ECE Board Exam April 1998 Which of the following refers to the smallest beam of a satellite antenna’s radiation pattern A. Global beam B. Spot beam

C. Zone beam D. Hemispheric beam

80.

ECE Board Exam April 1998 One of the FM signal generator control which varies the phase of the modulating voltage applied to the oscillator of the sweep generator A. B. C. D.

81.

Band control Phase control Marker amplitude control Sweep output control

ECE Board Exam April 1998 What consists the front-end circuit of a VHF TV superheterodyne receiver? A. B. C. D.

82.

Mixer, RF amplifier and AFC? RF amplifier, Band pass filter and mixer Local oscillator, mixer and RF amplifier Local oscillator, AGC and antenna

ECE Board Exam April 1998 One of the following prevents a transmitter from emitting a signal that interferes with other stations on frequency during the test. A. B. C. D.

83.

Use of low height antenna Use of grounded antenna Use of dummy antenna Use of shielded antenna radiator

ECE Board Exam April 1998 A transmission line consisting of two conductors that have equal resistance per unit length. A. B. C. D.

Unbalanced line Open-wire line Balanced line Coaxial line

84.

ECE Board Exam April 1998 How do you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? A. B. C. D.

85.

Use new power supply Lossen power supply shielding Use of regulated power supply Use of high capacitor in the supply circuit

ECE Board Exam April 1998 Which of the following is not common transmission line impedance? A. B. C. D.

86.

50 ohms 120 ohms 75 ohms 650 ohms

ECE Board Exam April 1998 How do you reduce the loss that is produced when light strikes a flat polished end of a fiber optic? A. B. C. D.

87.

By painting the surface By inclining the surface By cooling By application of antireflection coating

ECE Board Exam April 1998 Best reason for pressurizing waveguides with dry air A. B. C. D.

88.

To maintain propagation To maintain temperature of the waveguide To reduce the possibility of internal arcing To increase the speed of propagation

ECE Board Exam April 1998 What is the device used in fiber optic communication which consist of a receiver transmitter use to clean up and amplify digital data moving in one direction and another in the opposite direction?

A. B. C. D.

89.

Optic compressors Optic retarders Optic isolator Optic regenerators

ECE Board Exam April 1998 Which of the following refers to the first active satellite? A. B. C. D.

90.

Telstar I Echo I Intelsat I Sputnik I

ECE Board Exam April 1998 In modulation technique, which of the following is referred to audible pitch? A. B. C. D.

91.

Width Frequency Harmonic Amplitude

ECE Board Exam April 1998 What do you call the phenomenon in digital circuits that describe the duration of time a digital signal passes a circuit? A. B. C. D.

92.

Transmission time Elapsed time Propagation delay Travel delay

ECE Board Exam April 1998 What is the major cause of atmospheric or static noise? A. B. C. D.

Sunspots Airplanes Meteor showers Thunderstorm

93.

ECE Board Exam April 1998 Which of the following is not referred to as data terminal equipment? A. B. C. D.

94.

Telephone set Printers Modem Computer

ECE Board Exam April 1998 _______ is referred as the difference between available power and power budget? A. B. C. D.

95.

Fade margin Power margin Nominal gain Power dissipation

ECE Board Exam April 1998 The conversion of digital signal into analog for purposes of transmitting into the telephone line is done through ______. A. B. C. D.

96.

ISDN Radio RS232C Modem

ECE Board Exam April 1998 Refers to the duration occupancy period of call during its use. A. B. C. D.

97.

Occupancy period Traffic time Use time Holding time

ECE Board Exam April 1998 In data communication the transmission of binary signals will require _______. A. Same bandwidth as analog B. More bandwidth than analog

C. Less bandwidth than analog D. Bigger cable diameter

98.

ECE Board Exam April 1998 Assuming a UHF frequency range of 405.0125 MHz to 405.0875 MHz at 25 kHz channeling plan, how many channels can you produce? A. B. C. D.

99.

2.5 ch. 2 ch. 4 ch. 3 ch.

ECE Board Exam April 1998 One of the following is a possible cause for a slow drift of frequency in a self-exited transmitter oscillator circuits resulting to a poor frequency stability. A. B. C. D.

100.

Loose shielding Heating of capacitor in the oscillator Poor soldered connections Faulty capacitor, resistor, tubes or resistors

ECE Board Exam April 1998 A modulation which does not follow the sine wave pattern, it produces undesirable harmonics such as spurious emission A. B. C. D.

0% modulated Over-modulated Unmodulated 100% modulated

Test Yourself – Exam 07 1. How far away is the radio horizon of an antenna 100ft high? A. 14.14 mi B. 40km C. 14.14 km D. 40 mi 2. What is the maximum line-of-sight distance between a paging antenna 250 ft high and a pager receiver 3.5ft of the ground? A. 25 km B.25mi C. 70.73 km D. 70.73 mi 3. What is the path attenuation between transmitter and receiver at a frequency of 1.2 Ghz and a distance of 11,000 mi? A. 119 dB B. 115dB C. 179dB D. 174dB 4. What is the uplink receiver frequency if the downlink transmitter is on channel 4 (3.84 Ghz)? A. 6.065 GHz B. 6.84 GHz C. 6.65 GHz D. 6.05 GHz 5. What is the maximum theoretical data rate of the above problem if one transponder is used for binary transmission? A. 36 Mbps B. 72 Mbps C.18 Mbps D. 144 Mbps 6. What is the quardband between transponder channels in the commercial C-band for satellite communications? A. 6 MHz B. 36 MHz C. 4 MHz D. 2 MHz

7. What is the typical satellite transponder bandwidth? A. 24 MHz B. 500 MHz C. 36 MHz D. 48 MHz 8. What is the bandwidth available in the commercial C-band? A. 1000 MHz B. 36 MHz C. 250 MHz D. 500 MHz 9. Which of the following is the uplink frequency in C-band? A. 5.925 GHz B. 4.2 GHz C. 7.425 GHz D. 3.7 GHz 10. How many transponder channels are realized in the commercial C-band without frequency re-use? A. 24 B. 12 C. 36 D. 48 11. Which band of frequencies used by military for its satellites and radar? A. C band B. X band C. L band D. P band 12. For navigation as well as marine and aeronautical communications and radar, ____ band is used. A. L B. K C. S D. J 13. What is the current frequency band given most attenuation for satellite communications? A. Ku B. C band C. J D. P

14. What satellite subsystem monitors onboard conditions such as temperature and battery voltage and transmits this data back to a ground station for analysis? A. Communications subsystem B. AKM C. TTC D. Transponder 15. Which of the following satellite subsystem provides stabilization in orbit and senses changes in orientation? A. Attitude control subsystem B. TTC C. AKM D. Transponder 16. What is the typical center frequency spacing between adjacent channels (transponders) in satellites? A. 36 MHz B. 40 MHz C. 500 MHz D. 4 MHz 17. Which of the following are uplinks in the Ku band? A. 14 to 14.5 GHz B. 11.7 to 12.2 GHz C. 14 to 15.5 GHz D. 11 to 11.5 GHz 18. What is considered as the most advanced satellite system developed for cellular telephones? A. Iridium B. Globalstar C. ANIK D. Molniya 19. What is the orbit of Motorola’s Iridium satellite system? A. Polar B. Equatorial C. Inclined elliptical D. Inclined equatorial 20. What band of frequencies do these satellites operate? A. L band B. Ka band C. C band D. Ku band

21. Iridium satellites can provide data communications of up ____ bps data rate. A. 1200 B. 4800 C. 2400 D. 3840 22. What satellite system is also known as Navstar? A. GPS B. Iridium C. Globalstar D. Intelsat 23. What is the orbit height of a GPS satellite? A. 10,898 nmi B. 10,898 mi C. 10,898 km D. 10, 898 m 24. What is the orbital period of each satellite in the GPS constellation? A. 6 h B. 12 h C. 5 h D. 15 h 25. What term is normally associated with specifying the location of a celestial body in space? A. Constellation B. Galaxy C. Satellite D. Ephemeris 26. What is the angle of inclination of GPS system? A. 55˚ B. 65˚ C. 105˚ D. 45˚ 27. What material is most often used for the outer covering of coaxial cables? A. PVC B. Teflon C. PE D. Polystyrene

28. What is the dielectric constant of polyethylene (PE) insulator? A. 2.5 B. 3.3 C. 2.27 D. 2.1 29. Polytetrafluoroethylene (PTFE) is also widely used insulator and is known as. A. polystyrene B. teflon C. ceramic D. bakelite 30. What is the characteristic impedance of a two-wire line with the following data: diameter = 0.023in., spacing =0.5 in., insulation = PE.? A. 300Ω B. 250Ω C. 305Ω D. 301Ω 31. What is the characteristic impedance of a coaxial line with the following data: inner diameter = 0.2 in., center conductor diameter = 0.06 in., insulation = Teflon. A. 200Ω B. 75Ω C. 50Ω D. 150Ω 32. A pair of current-carrying conductors is not considered a transmission line unless it is at least ___ λ long at the signal frequency. A. 0.1 B. 0.3 C. 0.2 D. 0.4 33. If the operating frequency is 450 MHz what length of a pair of conductors is considered to be a transmission line? A. 2.19 ft B. 2.19 m C. 0.219 ft D. 0.219 m 34. What is the physical length of the above transmission line at 3/8λ long? A.0.82 m B. 0.82 ft C. 0.82 in D. 0.82 cm

35. Which of the following coaxial cable connectors is called the UHF connector? A. PL-259 B. BNC C. N-type connector D. F connector 36. What connector is popular in attaching test instruments like oscilloscopes, frequency counters, spectrum analyzers, etc? A. UHF connector B. PL-259 C. BNC D. SMA 37. Which coaxial cable connector is least expensive and is widely used for TV sets,VCRs and cable TV? A. N-type connector B. F-type connector C. BNC D. PL-259 38. Which coaxial connector is a more complex and expensive but do a better job in maintaining the electrical characteristics of the cable through the interconnections? A. N-type connector B. F-type connector C.BNC D. PL-259 39. The velocity factor in transmission lines vary from ___ to ___. A. 0.6 to 0.8 B. 0.3 to 0.5 C.0.5 to 0.9 D. 0.8 to 0.9 40. What is the typical velocity factor of coaxial cables? A. 0.6 to 0.8 B. 0.3 to 0.5 C. 0.5 to 0.9 D. 0.4 to 0.6 41. What is the typical velocity factor of open-wire line? A. 0.9 B. 0.8 C. 0.5 D. 0.7

42. What line has a typical velocity factor of about 0.8? A. Shielded pair B. Flexible coaxial C. Twin-lead D. Open-wire line 43. What is the velocity factor of coaxial cable with a characteristic impedance of 50Ω and capacitance of 30pF/ft and inductance of 75 nH/ft? A. 0.58 B.0.68 C. 0.98 D. 0.81 44. What is transit time (time delay) of a 50-ft length transmission line of the above problem? A. 50 ns B. 100 ns C. 75 ns D. 65 ns 45. What do you call a transmission line used specifically for the purpose of achieving delay? A. Delay line B. Flat line C. Resonant line D. Non-resonant line 46. What is the time delay introduced by a 75-ft coaxial cable with a dielectric constant of 2.3? A. 1.54 ns B. 11.5 ns C. 115.6 ns D. 1156 ns 47. Assume a frequency of 4 MHz, determine the phase shift offered by the line in the above problem. A. 108.5˚ B. 106.5˚ C. 115.5˚ D. 166.5˚ 48. Find the load impedance that must be used to terminate RG-62A/U to avoid reflections? A. 93Ω B. 75Ω C. 50Ω D. 300Ω

49. Find the equivalent inductance per foot of the above cable? A. 13.5 nF/ft B. 13.5 pF/ft C. 116.8 nH/ft D. 116.8 pF/ft 50. An RG-11/U foam coaxial cable has a maximum voltage standing wave of 52 V and a minimum voltage of 17 V. Find the value of the resistive load. A. 24.59Ω B. Either A or C C. 228.75Ω D. Neither A nor C 51. Sound provides all sorts of information. What information is related to mental processes of knowledge, reasoning, memory, judgement and perception? A. Cognitive B. Affective C. Digital D. Analog 52. What sound characteristic relates to a sonic time pattern? A. Tempo B. Attack C. Rhythm D. Timbre 53. What is considered the most obvious conveyor of information? A. Sound B. Speech C. Music D. Noise 54. Attack is a sound characteristic that refers to the way a sound begins. Which of the following is NOT an attack of sound? A. Hard B. Soft C. Crisp D. Simple 55. At what loudness level do pitch (in mels) and frequency (in Hz) are numerically equal? A. 0 dB B. 20 dB C. 60 dB D. 40 dB

56. The basic voice band has how many octaves? A. 10 B. 4 C. 5 D. 3 57. The ratio of frequencies is termed. A. interval B. octave C. harmonics D. factor 58. What is the tonal ratio of an octave? A. 1 to 2 B. 1 to 3 C. 2 to 1 D. 3 to 1 59. If the loudness level is 100 phons, what is this in sone unit? A. 100 B. 90 C. 106 D. 96 60. What octave bands are there in the midrange? A. 1st and 2nd B. 5th, 6th and 7th C. 3rd and 4th D. 8th and 9th 61. How much louder is 80 phons over 60 phons? A. 1000 times B.4 times louder C. 100 times D. Twice as loud 62. What increase in sound level is commonly perceived by most people? A. 6 to 10 dB B. 1 to 3 dB C. 3 to 6 dB D. 10 to 20dB

63. What is typical loudness level of an acoustic guitar 1 foot away? A. 60dB B. 100dB C. 80dB D. 40dB 64. What do you call the perceptible sound repetition? A. Reverberation B. Echo C. Reflection D. Masking 65. What is the amount of sound reduction provided by a barrier – wall, floor, or ceiling called? A. Sound Attenuation B. Transmission loss C. Sound absorption D. Barrier loss 66. What is the frequency of a 2-cm sound wave in sea water at 25˚C? A. 76 kHz B. 76 Hz C. 76 MHz D. 76 mHz 67. A choir consisting of 36 individuals all of whom can sing with the same intensity. A soloist sings a certain passage and then is joined by the remainder of the choir members for a repeat of the passage. What is the difference in the sound intensity level in the two cases? A. 3 dB B. 6 dB C. 36 dB D. 15.6dB 68. For the safety and comfort of factory workers, the sound-intensity level in a certain factory must remain below 85 dB. What is the maximum sound intensity allowed in this factory? A. 3.2 x 10-4 W/m2 B. 3.2 x 10-6 W/m2 C. 3.2 x 10-10 W/m2 D. 3.2 x 10-3 W/m2 69. What sound intensity corresponds to a sound-intensity level of 50dB? A. 1 x 10-6W/m2 B. 1 x 10-7W/m2 C. 1 x 10-8W/m2 D.1 x 10-5W/m2

70. The sound intensity received from the nearby jet plane is 12.6 µW/m2 and that from another jet plane some distance away is 0.45 µW/m2. Find the relative loudness of the two. A. 14.0 dB B. 14.5dB C. 12.5 D. 14.5 71. The noise from an airplane engine 100 ft from an observer is found to have an intensity of 45dB. What will be the intensity when the plane flies overhead at an altitude of 1 mi? A. 10.5 dB B. 34.5 dB C. 35 dB D. 20.5 dB 72. What is the apparent loudness of 80 dB? A. Moderate B. Very loud C. Loud D. Deafening 73. What loudness level in which permanent damage to hearing is possible? A. 120 dB B. 140 dB C. 130 dB D. 150 dB 74. What is sound pressure level if the RMS sound pressure is 100 μbars? A. 114 dB B. 11.4 dB C. 94 dB D. 57 dB 75. What is the velocity of sound in wood (m/s)? A. 330 B. 3600 C. 3300 D. 5800 76. What is the optimum reverberation time at 500 to 1000 Hz of an auditorium? A. 0.9 to 1.1 s B. 1.4 to 1.6 s C. 1.5 to 1.6 s D. 1.6 to 1.8 s

77. For a cinema, the optimum volume per person required is A. 3.1 B. 2.8 C. 7.1 D. 4.2 78. Which of the following is NOT an acoustical defect to be avoided in acoustical designs? A. Reverberation B. Flutter echo C. Distortion D. Sound concentration 79. What absorber in which efficient absorption is only possible over a very narrow band approaching 1.0 (total absorption)? A. Porous material B. Helmholtz resonator C. Panel Absorber D. Membrane absorber 80. How many voice signals (4 kHz max.) would fit into a 5 MHz spectrum? A. 1250 B. 500 C. 1000 D. 1500 81. How many FM stations would be accommodated I an ordinary TV channel? A. 33 B. 30 C. 40 D. 25 82. What is the actual length in feet of a one-quarter wavelength of a coax with a velocity factor of 0.695 at 45 MHz? A. 17.82 B. 19.26 C. 16.28 D. 16.97 83. Determine the terrain sensitivity loss for a 4-GHz carrier that is propagating over a very dry, mountainous area. A. -1.25 dB B. -3.05 dB C. -2.01 dB D. -5.01 dB

84. A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. A. 50 B. 69 C. 49 D. 30 85. A radio signal moves from air to glass. The angle of incidence is 20°. Calculate the angle of refraction. The relative permittivity of the glass is 7.8. A. 7.8° B. 5.04° C. 6.04° D. 7.04° 86. At a certain time, the MUF for transmission at an angle of incidence of 75° is 17 MHz. What is the critical frequency? A. 4.4 MHz B. 3.5 MHz C. 6.5 MHz D. 1.5 MHz 87. A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? A. 10 W B. 7.2 W C. 9.9 W D. 9.1 W 88. The electromagnetic radiation theory was profounded by A. Sir Edward Appleton B. Guglielmo Marconi C. Heinrich Hertz D. James C. Maxwell 89. What is caused by the transverse nature of electromagnetic waves? A. Polarization B. Interference C. Beamwidth D. Gain 90. Which propagation method is known as special case of skywave? A. Space wave B. Troposcatter C. Ground wave D. Direct wave

91. What is the orbit inclination of geostationary satellites? A. 0° B. 10° C. 20° D. 30° 92. A transmission line of unknown impedance is terminated with two different resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the line? A. 100 Ω B. 212 Ω C. 300 Ω D. 112 Ω 93. What is the high frequency sound that cannot be heard by the human ear? A. Ultrasonic B. Transonic C. Subsonic D. Supersonic 94. What frequency is 10 octaves above 30 Hz? A. 30.72 kHz B. 30 kHz C. 300 Hz D. 307.2 kHz 95. A radio signal travels ____ yards per microseconds. A. 273 B. 328 C. 618 D. 123.6 96. What is the actual length in feet of a one-half wavelength of a coax with a velocity factor of 0.63 at 28 MHz? A. 44.28 B. 43.46 C. 11.07 D. 46.27 97. The range of speech power is ____. A. 1 – 10 watts B. 100 – 1000 milliwatts C. 10 – 100 milliwatts D. 10 – 1000 microwatts

98. What is the actual length in feet of a one-quarter wavelength of a coax with a velocity factor of 0.68 to 30 MHz? A. 19.26 B. 5.6 C. 17.82 D. 16.97 99. What is actual length in feet of a one-half wavelength of a coax with a velocity factor of 0.59 at 26 MHz? A. 11.16 B. 40.29 C. 42.46 D. 46.28 100. The agreed standard for measuring loudness is the loudness sensation produced by a 1000 Hz sine wave _____ dB above the listener’s threshold of hearing. A. 80 B. 50 C. 30 D. 40

Test Yourself – Exam 08 1. What is the refractive index of an ionospheric layer with 100x105 free electrons per m3? Assume frequency to be at 20 MHz. A. 0.99 B. 0.15 C. 0.78 D. 0.85 2. “Each point on a spherical wavefront may be considered a source of secondary spherical wavefronts”. This is known as the A. Snell’s law B. D’Alembert’s principle C. Appleton’s theory D. Huygen’s principle 3. What is meant by the term deviation ratio? A. The ratio of the audio modulating frequency to the center carrier frequency. B. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency. C. The ratio of the carrier center frequency to the audio modulating frequency. D. The ratio of the highest audio modulating frequency to the average audio modulating frequency. 4. What is the major cause of selective fading? A. Small changes in the beam heading at the receiving station. B. Large changes in the height of the ionosphere, as experience at the receiving station. C. Time differences between the receiving and transmitting stations. D. Phase differences between radio wave components of the same transmission, as experienced at the receiving station. 5. What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? A. E-layer skip. B. D-layer skip. C. Auroral skip. D. Radio waves may be bent. 6. What propagation condition is usually indicated when a VHF signal is received from a station over 500 miles away? A. D-layer absorption B. Faraday rotation C. Tropospheric ducting D. Moonbounce 7. What is meant by the term modulation index? A. The processor index.

B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. C. The FM signal-to-noise ratio. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency. 8. The bending of radio waves passing over the top of a mountain range that disperses a weak portion of the signal behind the mountain is A. eddy-current phase effect B. knife-edge diffraction C. shadowing D. mirror refraction effect 9. What is the wavelength of a signal at 500 MHz? A. 0.062 cm B. 6 meters C. 60 cm D. 60 meters 10. What is included in the total resistance of an antenna system? A. Radiation resistance plus space impedance B. Radiation resistance plus transmission resistance C. Transmission line resistance plus radiation resistance D. Radiation resistance plus ohmic resistance 11. What are electromagnetic waves? A. Alternating currents in the core of an electromagnet B. A wave consisting of two electric fields at right angles to each other C. A wave consisting of an electric field and a magnetic field at right angles to each other D. A wave consisting of two magnetic fields at right angles to each other 12. The band of frequencies least susceptible to atmospheric noise and interference is: A. 30 – 300 kHz B. 300 – 3000 kHz C. 3 – 30 MHz D. 300 – 3000 MHz 13. What is the relationship in degrees of the electrostatic and electromagnetic fields of an antenna? A. 0 degree B. 45 degrees C. 90 degrees D. 180 degrees 14. For a space wave transmission, the radio horizon distance of a transmitting antenna with a height of 100 meters is approximately:

A. 10 km B. 40 km C. 100 km D. 400 km 15. What is meant by referring to electromagnetic waves as horizontally polarized? A. The electric field is parallel to the earth. B. The magnetic field is parallel to the earth. C. Both the electric and magnetic fields are horizontal D. Both the electric and magnetic fields are vertical 16. What is meant by referring to electromagnetic waves as having circular polarization? A. The electric field is bent into a circular shape. B. The electric field rotates C. The electromagnetic wave continues to circle the earth D. The electromagnetic wave has been generated by a quad antenna 17. If a transmitting antenna is 100 meters high and a separate receiving antenna is 64 meters high, what is the maximum space wave communication distance possible between them? A. 18 km B. 72 km C. 164 km D. 656 km 18. A receiver is located 64 km from a space wave transmitting antenna that is 100 meters high. Find the required height of the receiving antenna. A. 36 meters high B. 64 meters high C. 100 meters high D. 182.25 meters high 19. Which of the following is not one of the natural ways a radio wave may travel from transmitter to receiver? A. Ground wave B. Micro wave C. Sky wave D. Space wave 20. Which of the following terrain types permits a ground wave to travel the farthest? A. Salt water B. Fresh water C. Sandy D. Rocky 21. What is the input terminal impedance at the center if a folded dipole antenna? A. 300 ohms

B. 72 ohms C. 50 ohms D. 450 ohms 22. What is the term used to describe a spread spectrum communications system where the center frequency if a conventional carrier is altered many time per second in accordance with a pseudo-random list of channels? A. Frequency hopping B. Direct sequence C. Time-domain frequency modulation D. Frequency compandored spread spectrum 23. What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial cable such as RG 8, 11, 58 and 59? A. 2.70 B. 0.66 C. 0.30 D. 0.10

24. If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? A. 70 watts B. 50 watts C. 25 watts D. 6 watts 25. What determines the velocity factor in a transmission line? A. The termination impedance B. The line length C. Dielectrics in the line D. The center conductor resistivity 26. What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier? A. Frequency hopping B. Direct sequence C. Binary phase-shift keying D. Phase compandored spread spectrum 27. Which of the following frequency bands is best suited for ground wave propagation? A. 30 to 300 kHz B. 300 kHz to 3 MHz

C. 3 MHz to 30 MHz D. 30 MHz to 300 MHz 28. Which of the following frequency bands is best suited for sky wave propagation? A. 30 to 300 kHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 3 GHz to 30 GHz 29. What is the seventh harmonic of a 100 MHz quarter wavelength antenna? A. 14.28 MHz B. 107 MHz C. 149 MHz D. 700 MHz 30. Which if the following layers of the ionosphere has no effect on sky wave propagation during the hours of darkness? A. D B. E C. F1 D. F2 31. Skip distance can be maximized by using the ____ radiation angle possible and the ____ frequency that will be refracted at that angle. A. lowest, lowest B. lowest, highest C. highest, lowest D. highest, highest 32. What is the meaning of the term “velocity factor” of a transmission line? A. The ratio of the characteristic impedance of the line to the terminating impedance B. The index of shielding for coaxial cable. C. The velocity of the wave on the transmission line multiplied by the velocity of light in a vacuum. D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum. 33. What is the term for the ratio of actual velocity at which a signal travels through a line to the speed of light in a vacuum? A. Velocity factor B. Characteristic impedance C. Surge impedance D. Standing wave ratio 34. Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

A. Skin effect is less pronounced in the coaxial cable B. RF energy moves slower along the coaxial cable C. The surge impedance is higher in the parallel feed line D. The characteristic impedance is higher in the parallel feed line 35. What would be the physical length of a tpical coaxial transmission line that is electrically one-quarter wavelength long at 14.1 MHz? A. 20 meters B. 3.51 meters C. 2.33 meters D. 0.25 meter 36. To obtain the most reliable sky wave propagation the ____ should be used. A. Lowest useable frequency (LUF). B. Maximum useable frequency (MUF). C. Optimum useable frequency (OUF). D. Critical frequency

37. What is the deviation ratio for an FM-phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3kHz? A. 60 B. 0.16 C. 0.6 D. 1.66 38. Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? A. 300 kHz to 3 MHz B. 3 MHz to 30 MHz C. 30 MHz to 300 MHz D. 300 MHz to 3 GHz 39. What is the frequency range of an aircraft’s radio altimeter? A. 962 MHz to 1213 MHz B. 329.15 MHz to 335.00 MHz C. 4250 MHz to 4350 MHz D. 108.00 MHz to 117.95 MHz 40. What type of transmission is radiated from an aircraft’s radio altimeter antenna? A. An amplitude modulated continuous wave B. A pulse position modulated UHF signal C. A differential phase shift keyed UHF signal D. A frequency modulated continuous wave

41. The polarization of a radio wave: A. Is perpendicular to the electrostatic field of the antenna B. Is the same direction as the electrostatic field of the antenna. C. Is the same direction as the magnetic field of the antenna. D. Is perpendicular to both the electrostatic and magnetic fields of the antenna. 42. A coaxial cable has 7dB of reflected power when the input is 5 watts. What is the output of the transmission line? A. 5 watts B. 2.5 watts C. 1.25 watts D. 1 watt 43. When is it useful to refer to an isotropic radiator? A. When comparing the gains of directional antennas B. When testing a transmission line for standing wave ratio C. When (in the northern hemisphere) directing the transmission in a southerly direction D. When using a dummy load to tune a transmitter 44. Most AM broadcasts employ ___ polarization while most FM broadcasts employ ___ polarization of the radio wave. A. vertical, vertical B. vertical, horizontal C. horizontal, vertical D. horizontal, horizontal 45. How does the gain of a parabolic dish type antenna change when the operating frequency is doubled? A. Gain does not change B. Gain is multiplied by 0.707 C. Gain increases 6 dB D. Gain increases 3 dB 46. What is the frequency range of an aircraft’s Very High Frequency (VHF) communications? A. 118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz) B. 108.000 MHz to 117.95 MHz C. 329.15 MHz to 335.00 MHz D. 2.0000 MHz to 29.999 MHz 47. What is a selective fading effect? A. A fading effect caused by small changes in beam heading at the receiving station. B. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station. C. A fading effect caused by large changes in the height of the ionosphere, as experienced at the receiving station

D. A fading effect caused by time differences between the receiving and transmitting stations. 48. If the velocity of propagation in a certain medium is 200x106 m/s, what is its refractive index? A. 1.3 B. 1.5 C. 1.27 D. 0.67 49. What is the resultant field strength at the receiving antenna in space wave propagation under case 2? A. 0 B. ξd C. 2ξd D. 3ξd

50. The decimetric wave is using what method of propagation? A. Ground wave B. Space wave C. Sky wave D. Tropospheric wave 51. What is the typical frequency used for communicating to submerged submarines? A. 100 Hz B. 500 Hz C. 4 kHz D. 200 Hz 52. Which frequency bands can be refracted during the day by the D layer? A. VLF B. MF C. LF D. Both VLF and LF 53. What height of an ionized layer is determined from the time interval between the transmitted signal and the ionospheric echo at vertical incidence? A. Virtual height B. Apparent height C. Actual height D. Effective height

54. During the night when the F2 layer combines with F1 layer it falls to what approximate height? A. 250 km B. 350 km C. 300 km D. 400 km 55. Which of the following is considered the most frequently used transmission line? A. Two-wire open line B. Twin lead C. Rigid coaxial line D. Flexible coaxial line 56. The antenna effective height is ____ to ____ of the actual height. A. ½ to 2/3 B. ½ to ¾ C. ¼ to 2/3 D. ¼ to ¾

57. What is the propagation velocity of a signal in a transmission line whose inductance and capacitance are 5μH/m and 20μF/m respectively? A. 100x103 m/s B. 100 m/s C. 10x103 m/s D. 100x106 m/s 58. What is the phase coefficient in radians per unit length of a transmission line at the frequency of 10 MHz if the velocity of propagation is 2.5x108 m/s? A. 0.25 B. 2.5 C. 0.35 D. 3.5 59. Determine the conductance of a two-wire open line with the following parameters: D = 4 in., d = 0.1 in. and ρ = 2.6x108 Ω-m. A. 2.76x10-9 S/m B. 2.76x10-6 S/m C. 2.76x10-12 S/m D. 2.76x10-3 S/m 60. What is the input impedance of a transmission line if its characteristic impedance is 300 Ω and the load is 600 Ω? Assume a quarter wavelength section only. A. 150 kΩ B. 150 mΩ C. 150 Ω

D. 2 Ω 61. Determine the standing wave ratio of a 300-Ω line whose load is 400+j150 Ω. A. 3.55 B. 1.67 C. 5.53 D. 3.35 62. What is the optimum volume per person of rooms for speech? A. 2.8 B. 3.1 C. 4.2 D. 5.1 63. What happens to the beamwidth of an antenna as the gain is increased? A. The beamwidth increases geometrically as the gain is increased. B. The beamwidth increases arithmetically as the gain is increased. C. The beamwidth is essentially unaffected by the gain of the antenna. D. The beamwidth decreases as the gain is increased. 64. A superhet receiver has an IF of 455 kHz and is experiencing image-channel interference on a frequency of 1570 kHz. The receiver is tuned to A. 1115 kHz B. 660 kHz C. 2025 kHz D. 910 kHz 65. What is the end impedance of a half-wave dipole? A. 73 Ω B. 72 Ω C. 250 Ω D. 2500 Ω 66. What volume of the chamber is required to measure absorption coefficient at 100 Hz? A. 125 m3 B. 50 m3 C. 150 m3 D. 352 m3 67. What is the optimum reverberation time at 500 Hz for a cinema? A. 0.8 – 1.2 sec. B. 0.9 – 1.3 sec. C. 0.6 – 0.8 sec. D. 0.45 – 0.55 sec.

68. An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to A. 131.8 MHz B. 110.4 MHz C. 142.5 MHz D. 99.7 MHz 69. A 1 Mhz carrier is amplitude modulated by a pure 200-Hz audio test tone. Which of the following combinations of frequencies represent the total content of the AM signal? A. 1 MHz and 200 Hz B. 1 MHz and 1000.2 kHz C. 999.8 kHz, 1000 kHz, and 1000.2 kHz D. 999.8 kHz and 1000.2 kHz 70. What establishes the receiver bandwidth? A. RF amplifier B. Mixer C. Local oscillator D. IF amplifier 71. What noise type is observable between 8 MHz to somewhat above 1.43 GHz or up to 1.5 GHz? A. Solar noise B. Space noise C. Galactic noise D. Cosmic noise 72. Flicker noise is a poorly understood form of noise which may be completely ignored about above ____. A.100 Hz B. 200 Hz C. 400 Hz D. 500 Hz 73. What is the typical gain of a rhombic antenna? A. Between 15 to 60 B. Between 20 to 90 C. Between 50 to 75 D. Between 10 to 25 74. What illumination factor is normally considered in computing parabolic antenna gain in microwave communications? A. 0.54 B. 0.65 C. 0.75

D. 0.85 75. How many voice band channels are there in a superjumbo group? A. 600 B. 900 C. 10,800 D. 3,600 76. In acoustics, what is the reference pressure in lb/ft2 unit? A. 2x10-5 B. 0.0002 C. 2.089 D. 2.980 77. Which of the following characterizes a properly terminated transmission line? A. The line loss is minimum. B. The standing wave ratio is minimum. C. The input impedance is twice the load impedance. D. The standing wave ratio is one.

78. What is the meaning of forward power? A. The power traveling from the transmitter to the antenna. B. The power radiated from the top of an antenna system. C. The power produced during the positive half of an RF cycle. D. The power used to drive a linear amplifier. 79. What organization has published safety guidelines for the maximum limits of RF energy near the human body? A. The American National Standards Institute (ANSI). B. The Environmental Protection Agency (EPA). C. The Federal Communications Commission (FCC). D. The Institute Of Electrical and Electronics Engineers (IEEE). 80. When no signal is being received, the loudspeaker is not entirely silent as a result of the presence of A. parasitic oscillations in some of the receiver stages. B. negative feedback in each stage. C. spurious frequencies as a result of improper neutralization. D. internal receiver noise. 81. When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage

D. final RF stage 82. When the is the ionosphere most ionized? A. Dusk B. Midnight C. Dawn D. Midday 83. Cellular radios use FM with a maximum deviation of A. B. C. D. 84. What device measures the angle between two radio frequencies and also the direction of propagation of a wave? A. Densimeter B. Absorption wavemeter C. Goniometer D. Ergometer 85. An automated ship-to-shore distress alerting system using satellites and advanced terrestrial communications systems. A. GPS B. Iridium system C. INMARSAT D. GMDSS 86. What antenna can be used to minimize the effect of Faraday rotation of polarization? A. Dipole B. Parabolic C. Helical D. Rhombic 87. The presence of standing waves on a transmission line is the result of A. a high level of attenuation on the line. B. terminating the line by a resistive load equal in value to the surge impedance C. reducing the input power to below its critical level. D. an impedance mismatch between the load and the line. 88. What device measures rf power by measuring the heat the rf power generates? A. Calorimeter B. Goniometer C. Spectrum meter D. Oscilloscope

89. What is considered the most efficient mode in terms of energy transfer in waveguides? A. Dominant mode B. Normal mode C. Conventional mode D. Vertical mode 90. In acoustics, _____ is the apparent change in frequency or pitch when a sound source moves either toward or away from a listener. A. flanking B. reverberation C. Doppler effect D. echo 91. Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5mm C. 1.35 dm and 1.7cm D. 1.5 cm and 5 mm

92. Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? A. 1.35 mm and 1.7 μm B. 1.35 cm and 1.7 mm C. 5 cm and 2.5 cm D. 5 mm and 2.5 mm 93. The approximate single-hop nighttime range of F2 layer is ____. A. 3000 km B. 3840 km C. 4130 km D. 2350km 94. What ionospheric layer has a daytime approximate critical frequency of 8 MHz? A. F2 layer B. F1 layer C. E layer D. D layer 95. In cellular system, _____ defines the geographic distance that is required between cells using identical frequencies in order to avoid interference between the radio transmissions at these cells. A. frequency-reuse ratio B. distance-to-reuse ratio (D/R) C. reuse format plan ratio D. reuse factor

96. What do you call the ability of a mobile phone to change from one channel (frequency) to another? A. Frequency agility B. Frequency handoff C. Frequency handover D. Frequency switch 97. What mathematical plane figure is ideal in cellular system design and engineering it graphically and functionally depicts overlapping radio coverage between and among adjacent cell base stations? A. Hexagon B. Octagon C. Pentagon D. Nonagon 98. In cellular system, the average lead time to install a new base station is approximately ____ months to a year. A. 4 B. 5 C. 6 D. 10 99. What is considered the threshold of audibility at 3000 Hz? A. 10-12 W/m2 B. 10-16 W/m2 C. 10-12 W/cm2 D. 10-15 W/cm2 100. At one atmospheric pressure, what is the approximate speed of sound in steel? A. 5150 m/s B. 5150 ft/s C. 4990 m/s D. 4990 ft/s

Test Yourself – Exam 09 1. What significant element of sound refers to its characteristic tonal quality? A. Pitch B. Tempo C. Rhythm D. Timbre 2. What is the velocity of sound in wood? A. 5800 m/s B. 5000 m/s C. 3300 m/s D. 3700 m/s 3. What is the typical loudness level of a watch ticking? A. 0 phon B. 40 phons C. 20 phons D. 60 phons 4. The typical length of the rhombic antenna is ____. A. 2λ to 8λ B. 10λ to 20λ C. 1λ to 3λ D. 5λ to 10λ 5. What is the carrier frequency of supergroup 10? A. 2724 kHz B. 2356 kHz C. 2108 kHz D. 3100 kHz

6. In SPADE system, how many PCM-encoded voice band channels are there? A. 800 B. 600 C. 300 D. 240 7. The product of the radiated RF power of a transmitter and the gain of the antenna system in a given direction relative to an isotropic radiator is called ____. A. Effective Radiated Power (ERP) B. Effective Isotropic Radiated Power (EIRP) C. Radiated Power D. Transmit Power

8. The product of antenna input power and the antenna power gain expressed in kW is called __. A. Effective Radiated Power (ERP) B. Effective Isotropic Radiated Power (EIRP) C. Radiated Power D. Transmit Power 9. What satellite system parameter represents the quality of a satellite or an earth station receiver? A. Gain-to-Equivalent Noise Temperature Ratio (G/Te) B. Energy of Bit-to-Noise Density Ratio (Eb/No) C. Carrier-to-Noise Density Ratio (C/No) D. Bit energy 10. What noise is observable at frequencies in the range from about 8 MHz to somewhat 1.5 GHz? A. Industrial noise B. Atmospheric noise C. Space noise D. Shot noise 11. A special horn antenna consisting of a parabolic cylinder joined to a pyramidal horn. A. Hoghorn B. Cass-horn C. Pyramidal horn D. Conical horn 12. How many telegraph channels are there in the basic voice band channels? A. 24 B. 96 C. 48 D. 672

13. Which of the following is oldest multiplexing scheme? A. Frequency Division Multiplexing (FDM) B. Time Division Multiplexing (TDM) C. Code Division Multiplexing (CDM) D. Space Division Multiplexing (SDM) 14. What carrier system multiplexes 96 voice band channels into a single 6.312 Mbps data signal? A. T1 carrier system B. T2 carrier system C. T1C carrier system D. T3 carrier system

15. What is the metric subdivision of VHF band? A. Metric B. Millimetric C. Decimetric D. Centimetric 16. In satellite communications, what means of attitude control is using the angular momentum of the spinning body to provide the roll and yaw stabilization? A. Spin stabilization B. Radial stabilization C. Three-axis stabilization D. Station keeping 17. Which of the following is NOT a porous absorber? A. Prefabricated tiles B. Plasters and spray on materials C. Acoustic blankets D. Membrane absorber 18. What historical satellite broadcasted live the 1964 Olympic games from Tokyo, Japan for the first time? A. Syncom I B. Syncom III C. Syncom II D. Syncom IV 19. In transmission line, which of the following is the first step in the procedure of using stub matching? A. Calculate stub susceptance. B. Calculate load admittance C. Connect stub to load D. Transform conductance to resistance 20. What type of balun (balanced-to-unbalanced) is used in high frequency applications? A. Transformer type balun B. A specially configured coaxial transmission line C. A specially configured parallel-wire line D. A λ/2 transformer balun 21. ____ is defined as any radiation of energy by means of electromagnetic wave. A. Emission B. Radiation C. Radio D. Broadcasting 22. In what year did Hertz discover radio waves?

A. 1844 B. 1873 C. 1887 D. 1895 23. Which of the following phenomena is possible is free space medium? A. Reflection of radio wave B. Diffraction of radio wave C. Refraction of radio wave D. Attenuation of radio wave 24. What is the reactance property at the input of a shorted quarter wavelength line? A. A parallel LC circuit B. A pure inductive reactance C. A series LC circuit D. A pure capacitive reactance 25. An early satellite owned by US Department of Defense that lasted only for 17 days A. Courier B. Echo C. Score D. Westar 1 26. Which of the following is the consolidation of H. No. 5224 and S. No. 2683? A. RA 9292 B. RA 5734 C. RA 7925 D. RA 6849

27. Who will appoint the chairman and 2 members of the board of Electronics Engineering? A. The Senate President B. The President C. The Supreme Court D. The Commission on Appointment 28. How many nominees per position of the Electronics Engineering Board are nominated by IECEP to PRC? A. 3 B. 5 C. 4 D. 6

29. According to RA 9292, how many days after the board exam the results will be released? A. Within 5 days B. Within 15 days C. Within 20 days D. Within 3 days 30. How many removal examination (s) will be given to an examinee who obtains a passing rating in the majority of the subjects but obtains a rating in the other subject (s) below seventy percent (70%) but not lower than sixty percent (60%)? A. 1 B. 3 C. 2 D. Unlimited 31. Which of the following determines the acoustic behavior of gases? A. Density B. Pressure C. Temperature D. All of the choices 32. In what medium sound travels the faster? A. Vacuum B. Solid C. Liquid D. Gas 33. For a loudness level between 110 and 120 dB, the maximum daily exposure limit is ____ minute (s). A. 1 B. 60 C. 20 D. 45 34. A porous material is far more efficient at high than low frequency absorption. How to improve sound absorption at lower frequencies using this absorber? A. Increase the thickness B. Decrease the thickness C. Mount with and airspace behind D. Both A and C above 35. Which of the following describes a TDM frame? A. A 250-μs frame B. A 125-μs frame C. A 500-μs frame D. A 60-μs frame

36. ____ system transmits frequency-division-multiplexed voice band signals over a coaxial cable for distances up to 4000 miles. A. T carrier B. X carrier C. L carrier D. F carrier 37. What is the spectrum range of U600 mastergroup? A. 60 – 108 kHz B. 564 – 3084 kHz C. 312 – 552 kHz D. 60 -2788 kHz 38. Which frequency reuse method is less effective because of Faraday’s effect? A. Dual polarization B. Reducing antenna beamwidth C. Zonal rotation D. Spin stabilization 39. Three telephone circuits, each having an S/N ratio of 44 dB, are connected in tandem. What is the overall S/N ratio? A. 44 dB B. 39.2 dB C. 41 dB D. 43.52 dB 40. What is the noise factor if the equivalent noise temperature is 25 K? A. 1.09 B. 0.09 C. 0.36 dBm D. 0.36

41. A ground station is operating to a geostationary satellite at a 5° angle of elevation. Calculate the round-trip time between ground station and satellite. A. 275 s B. 275 ms C. 137.5 s D. 137.5 ms 42. Calculate the reverberation time of a living room 8 ft high, 13 ft wide and 20 ft long. The total absorption of the building structure inside the room is 180.7 sabines with four persons present in the room. A. 0.5 ms B. 0.05 s C. 0.5 s

D. 5 ms 43. What is the number of levels required in a PCM system with S/N ratio of 40 dB? A. 64 B. 128 C. 256 D. 512 44. A radio communications link is to be established via the ionosphere. The maximum virtual height of the layer is 100 km at the midpoint of the path and the critical frequency is 2 MHz. The distance between stations is 600 km. determine the optimum working frequency? A. 6.32 MHz B. 2.1 MHz C. 5.4 MHz D. 1.8 MHz 45. Part of a microwave link can be approximated by free space conditions. The antenna gain are each 40 dB, the frequency is 10 GHz, and the path length is 80 km. Calculate the receive power for a transmitted power of 10 W? A. 0.871 μW B. 871 μW C. 0.871 mW D. 871 nW 46. What is the approximate critical frequency of the E layer? A. 4 MHz B. 5 MHz C. 6 MHz D. 3 MHz

47. What is the approximate single-hop nighttime range of F2 layer? A. 3840 km B. 3000 km C. 4130 km D. 2350 km 48. What ionospheric layer has a daytime approximate critical frequency of 8 MHz? A. F2 layer B. F1 layer C. E layer D. D layer 49. Determine the additional absorption (sabines) contributed by 10 persons in a room.

A. 47 B. 4.7 C. 0.47 D. 470 50. A frequency of 3000 Hz has how many octaves above 1000 Hz? A. 1.6 octaves B. 2.1 octaves C. 1 octave D. 3 octaves 51. The loudness level increased from 40 to 56 phons. What is the increase in loudness sensation? A. 3 times B. 4.5 times C. 2 times D. 4 times 52. In the North American TDM system, what is the transmission rate in Mbps of T3 carrier system? A. 44.736 B. 6.312 C. 3.152 D. 274.176 53. What is the data rate in Mbps of a single satellite transponder considering an S/N of 30 dB? A. 35.8 B. 3.58 C. 358 D. 3580

54. What condition occur when the refractive index of the air decreases with height much more rapidly the normal? A. Refraction B. Superrefraction C. Subrefraction D. Diffraction 55. What do you call the increase of temperature with height? A. Temperature inversion B. Normal inversion C. Ducting D. Superrefraction 56. ____ is a term given to the region where superrefraction occurs.

A. Strata B. Duct C. Isothermal region D. Tropospheric region 57. Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5 mm C. 1.35 dm and 1.7 cm D. 1.5 cm and 5mm 58. Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? A. 1.35 cm and 1.7 mm B. 5 mm and 2.5 mm C. 5 cm and 2.5 cm D. 1.35 mm and 1.7 μm 59. What instrument normally measures the virtual height of ionosphere? A. Ionosonde B. Altimeter C. Field meter D. Radar 60. The angle of elevation of the antenna beam is 20°. Calculate the transmission-path distance for an ionospheric transmission that utilizes a layer of virtual height 200 km. Use flat-earth approximation. A. 966 km B. 2100 km C. 1100 km D. 405 km 61. If temperature change is 19°C, what amount of change to sound velocity is possible? A. 11.53 ft/s B. 11.53 m/s C. 19.304 ft/s D. 19.304 m/s 62. In the above problem, what is the new velocity of sound assuming dry air medium? A. 343 ft/s B. 3430 m/s C. 343 m/s D. 342 m/s 63. In acoustics, if the volume of the room is 200 m3 then at what frequency the coefficient of absorption is measured?

A. 120 kHz B. 120 Hz C. 100 Hz D. 150 Hz 64. What is the approximate bandwidth of an FM system with 10 kHz of modulating frequency and a 150 kHz of frequency deviation? A. 300 kHz B. 320 kHz C. 150 kHz D. 200 kHz 65. Which of the following layers of the ionosphere has no effect on sky wave propagation during daytime? A. D B. E C. F1 D. F2 66. What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? A. Diffraction B. Ducting C. Reflection D. Refraction 67. How to maximize the skip distance? A. Using the smallest possible radiation angle and highest possible frequency B. Using the smallest possible radiation angle and lowest possible frequency C. Using the biggest possible radiation angle and highest possible frequency D. Using the biggest possible radiation angle and lowest possible frequency 68. For a space wave transmission, the radio horizon distance of a receiving antenna with a height of 64 meters is approximately A. 8 km B. 32 km C. 64 km D. 256 km 69. What bandwidth is needed to support a capacity of 128 kbps when the signal power to noise power ratio in decibels is 100? A. 19224 Hz B. 3853 Hz C. 19244 Hz D. 3583 Hz

70. Which of the following systems uses frequency band 870-885 MHz as a transmit band of its base station? A. TACS B. NTT C. NMT D. AMPS 71. A transmitted signal 5 meters in wavelength is received by an antenna coil having a 50-Ω resistance and a 0.01 H inductance. What is the capacitance of the tuner shunting the antenna coil at this point? A. 0.704 fF B. 0.704 μF C. 0.704 nF D. 0.704 mF 72. Which of the following is the basic component of a communications satellite receiver? A. On-board computer B. Reflector C. Telemetry D. Transponder 73. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find the absorption effect of the materials used in metric sabines. A. 35.3 B. 10.96 C. 379.8 D. 109.6

74. What is the highest frequency that can be sent straight upward and be returned to earth? A. MUF B. Gyro frequency C. Skip frequency D. Critical frequency 75. What is the most important specification of loudspeakers and microphones? A. Frequency response B. Power density C. Field Strength D. Gain 76. Atmospheric attenuation is an attenuation which is due to A. mist and fog

B. gasses in the atmosphere C. water vapor and oxygen D. rain 77. Satellite orbits around the earth are ____ orbits. A. circular B. either elliptical or circular C. elliptical D. circular only 78. How does spatial isolation technique in satellite communications avoid interference? A. Use of different polarity antennas B. Use of different types of antennas C. Employment of highly directional spot-beam antennas D. Use of low gain antennas 79. An area on earth covered by a satellite radio beam is called ____. A. SSP B. Region C. footprint D. primary area 80. The American concert pitch A is equivalent to which if the following frequencies? A. 440 Hz B. 435 Hz C. 260 Hz D. 255 Hz

81. The international pitch A is equivalent to ___ Hz. A. 435 B. 440 C. 260 D. 255 82. The speed of the satellite increases as its height in orbit gets A. lower B. higher C. closer to the moon D. closer to the sun 83. What is the effective radiated power of a repeater with 50 watts transmitter power output \, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain?

A. 158 W B. 39.7 W C. 251 W D. 69.9 W 84. A cellular standard known as the cdmaOne. A. IS-95 B. IS-136 C. IS-54 D. IS-100 85. What is the effective radiated power of a repeater with 50 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna gain? A. 300 W B. 315 W C. 31.5 W D. 69.9 W 86. Which Ethernet system is restricted only to 100 m? A. 10 Base T B. 20 Base 2 C. 10 Base 5 D. 10 Base 1 87. What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain? A. 600 W B. 75 W C. 18.75 W D. 150 W 88. Which of the following regulates the ownership and operation of radio and television stations in the country? A. PD 576-A B. PD 756 C. PD 657 D. PD 677 89. What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? A. 37.6 W B. 237 W C. 150 W D. 23.7 W 90. In GSM cellular system, the speech coding rate is ____.

A. 13 kbps B. 8 kbps C. 15 kbps D. 20 kbps 91. What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 800 W B. 126 W C. 12.5 W D. 1260 W 92. Which NTC memorandum circular governs the rules and regulations about the manufacture, acquisition, sale and service of radio communication equipment? A. MC No. 2-05-88 B. MC No. 2-04-88 C. MC No. 2-07-88 D. MC No. 2-09-88 93. What is the effective radiated power of a repeater with 120 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? A. 601 W B. 240 W C. 60 W D. 379 W 94. What do you call a short bit sequence sent typically 128 bits in digital signatures? A. Hash B. Public key C. Private key D. Password 95. What medium is used by IBM token ring network that operates at either 4 Mbps or 16 Mbps? A. Twisted pair B. Coaxial cable C. Fiber-optic D. Parallel-wire line 96. What is known as the final stage in the evolution of the GSM standard? A. WAP B. GPRS C. EDGE D. Bluetooth 97. According to KBP revised radio code which airtime below is classified class D for AM stations? A. 6:00 AM to 12:00 NN

B. 12:00 NN to 6:00 PM C. 9:00 PM to 12 Midnight D. 12:00 Midnight to 5:00 AM 98. Encryption of data is important to ensure its privacy. It is most commonly achieved by using a ____. A. public-key encryption B. private-key encryption C. password-key encryption D. character set encryption 99. The speech coding rate in D-AMPS is ____. A. 8 kbps B. 13 kbps C. 15 kbps D. 20 kbps 100. Which of the following principal musical intervals is considered dissonant? A. 7:8 B. 1:2 C. 5:8 D. 3:5

Test Yourself – Exam 10 1.

________ is a standard whereby mobile phones can gain access to specially tailored Internet websites. A. Bluetooth B. GPRS C. WAP D. EDGE

2.

What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system? A. Flicker noise B. Transit-time noise C. Shot noise D. Impulse noise

3.

What is the insertion loss of connector type splices for a single mode optical fiber? A. 0.51 dB B. 0.49 dB C. 0.31 dB D. 0.38 db

4.

In the European standard, the aurial transmitter maximum radiated power is ______ of peak visual transmitter power. A. 10% B. 30% C. 20% D. 40%

5.

What is the common up-converter and down-converter IF for microwave communications? A. 60 MHz B. 80 MHz C. 120 MHz D. 70 MHz

6.

What is the data link protocol that is used in asynchronous transmission for transferring files from one computer to another? A. A modem B. X modem C. B modem

D. C modem 7.

What distortion is not caused by transmission line characteristics? A. Phase distortion B. Pulse shape distortion C. Spacing bias distortion D. Amplitude distortion

8.

What is the effective radiated power of a repeater with 200 watts transmitter power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 317 W B. 2000 W C. 126 W D. 260 W

9.

Which of the following is standardized as part of GSM phase 2+ that can offer theoretical data speeds of upto 115 kbit/s? A. EDGE B. GPRS C. WAP D. Bluetooth

10. A ______ is essentially a cell site that is mounted on a flatbed tractor-trailer used for emergency purposes. A. COW B. BULL C. CALF D. PONY 11. Which of the following best describes a dip-meter? A. An SWR meter B. A counter C. A variable LC oscillator with metered feedback current D. A field strength meter 12. Which is space diversity system? A. Two or more antennas operating on two different frequencies? B. Two transmitters operating at same frequencies C. Two or more antennas operating on the same frequency D. Two antennas from two different transmitters

13. What part or section of a TV receiver that separates the sound and video signals? A. IF stage B. Video amplifier C. Video detector D. Burst separator 14. What is the channel number of an FM station with a carrier frequency of 99.5 MHz? A. 256 B. 258 C. 257 D. 259 15. In a triple conversion superheterodyne receiver, diode mixer stages are operated A. In the linear region B. In the nonlinear region C. As class A amplifiers D. As class B amplifiers 16. In ISDN, what is the basic access B channel data rate? A. 32 kbps B. 64 kbps C. 144 kbps D. 16 kbps 17. What is the channel spacing for MF-HF voice frequencies? A. 2.8 kHz B. 500 Hz C. 3.5 kHz D. 3 kHz 18. What is the quantization signal-to-noise ratio if an 8-bit PCM code is used? A. 40 dB B. 50 dB C. 60 dB D. 65 dB 19. What is the emission designation of a single sideband reduced carrier signal? A. H3E B. J3E

C. R3E D. B8E 20. What is the most commonly used intermediate frequency of radar receivers? A. 40 MHz B. 60 MHz C. 70 MHz D. 30 MHz 21. The input signal of a travelling wave tube is introduced at A. Cathode B. Anode C. Cathode end of the helix D. Collector end of the helix 22. What determines the ability of radar to determine the bearing to a target? A. Speed of light B. Speed of target C. Antenna directivity D. Frequency of signal 23. What is the minimum number of bits required in a PCM code for a range of 10,000? A. 12 B. 9 C. 14 D. 10 24. The antenna current is doubled when the modulation index is doubled in ______ AM system. A. A5C B. A3J C. A3 D. A3H 25. Which of the following is not a bounded medium? A. Coaxial line B. Two-wire line C. Waveguide D. Free space

26. What is affected by the distance between the listener and the source of the sound because the intensity varies inversely with the square of the distance? A. Volume B. Pitch C. Loudness D. Frequency 27. Comparing the capacities of a DVD and an ordinary CD, DVD is ______ time bigger than CD. A. 10 B. 20 C. 15 D. 25 28. Locking on to a defined target is known as A. Homing B. Referencing C. Searching D. Defining 29. What causes the maximum usable frequency to vary? A. The temperature of the ionosphere B. The speed of the winds in the upper atmosphere C. The type of weather just below the ionosphere D. The amount of radiation received from the sun 30. What limits the sensitivity of a receiver? A. The power supply of the receiver B. The power output of a transmitter C. The noise floor of the receiver D. The distance between the transmitter and receiver 31. What is the standard test tone used for audio measurements? A. 100 Hz B. 500 Hz C. 1000 Hz D. 2000 Hz 32. What causes image interference? A. Low gain

B. High IF C. Poor front-end selectivity D. Low signal-to-noise ratio 33. What frequency band is referred to as the metric waves? A. VHF B. UHF C. HF D. SHF 34. A waveguide passive component that brings a smooth change in the direction of axis maintained perpendicular to the plane of polarization? A. L bend B. H bend C. T bend D. X bend 35. How far is the visual carrier from the lowest frequency in the spectrum of a monochrome TV broadcast channel following the NTSC standard? A. 1.5 MHz B. 1.25 MHz C. 4.5 MHz D. 0.25 MHz 36. What aircraft deviation is measured by an ILS localizer? A. Altitude B. Ground speed C. Vertical D. Horizontal 37. Skip zone is otherwise known as A. Empty zone B. Shadow zone C. Null zone D. Zone of silence 38. In the American standard, the aural transmitter maximum radiated power is _____ of peak visual transmitter power. A. 10 % B. 30 %

C. 20 % D. 40 % 39. What character signifies the start of the test for Bisync? A. STX B. SOH C. BCC D. ETX 40. A low frequency audible periodic variation in pitch of sound output in high fidelity sound reproduction system? A. Flutter B. Wow C. String vibration D. Radio sound 41. When can a corporation or association incorporated under the Philippine laws and with foreign investors be granted radio station license? A. When 60% of the capital is owned by Filipino citizens B. When 50% of the capital is owned by Filipino citizens C. When the chairman of the board is a Filipino D. When the president of the corporation/association is a Filipino 42. ______ is a term in the test language for noise testing in telephone circuits that means a one-syllable word consisting of a consonant, a vowel, and another consonant. A. Logatom B. Nosfer C. Ore D. Belcore 43. Why are frequency modulation transmitters more efficient? A. Because their power is increased by class C amplifiers B. Because their power is increased by class A amplifiers C. Because their power is increased by class B amplifiers D. Because their power is increased by class AB amplifiers 44. A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total power of the modulated wave? A. 1361.25 W B. 680.62 W

C. 1425 W D. 712.5 W 45. Which is not an ITU sector? A. ITU-W B. ITU-R C. ITU-T D. ITU-D 46. What is the process of cancelling the effect on internal device capacitance in radio transmitters? A. Degaussing B. Neutralization C. Ionization D. Stabilization 47. Which of the following is the basic synthesizer circuit? A. Frequency divider B. Frequency multiplier C. PLL D. Mixer 48. Which one is not an important characteristic of the physical layer? A. Electrical B. Logical C. Mechanical D. All of the choices 49. What is the typical separation between the two conductors in a parallel wire line? A. 0.001 to 0.01 m B. 200 to 500 mm C. 0.635 to 15.24 cm D. 2.5 to 5 in. 50. In t-carrier system, t3 has a bit rate of A. 560.160 Mbps B. 44.376 Mbps C. 44.736 Mbps D. 560.106 Mbps

51. In radio signal emission designation, the fifth symbol means A. Details of signals B. Type of information transmitted C. Nature of multiplexing D. Nature of signal modulating the main carrier 52. What is the channel spacing for SITOR frequencies? A. 500 Hz B. 170 Hz C. 300 Hz D. 3 kHz 53. Which of the following is the new name of CCITT? A. ITU-T B. ITU-R C. ITU-S D. ITU-D 54. Which of the following frequencies is normally used for distress and safety communications? A. 4209.5 kHz B. 490 kHz C. 518 kHz D. 2174.5 kHz 55. What is the difference between available power and power budget? A. Power margin B. Extra power C. Fade margin D. System gain 56. A matched termination in which the electromagnetic energy is absorbed by water. A. Maximum power transfer B. Load C. Load water D. Basin 57. What do you call the electrical conduction in a photosensitive material which is not exposed to radiation? A. Dark conductance

B. Pure conductance C. Black out D. Super conductance 58. How many sidebands are present in the J3E mode? A. Two sidebands and a carrier B. One upper sideband C. One lower sideband D. Two carriers and one sideband 59. A component that samples the microwave signal travelling in one direction down to the transmission line A. Isolator B. Combiner C. Directional coupler D. Attenuator 60. What does OMB stand for? A. Optical media board B. Organization of medical biologist C. Optical medium board D. Optimum main board 61. A test method of comparing two audio systems by switching inputs so that the same recording is heard in rapid succession over one given system and then the other. A. B test B. A test C. AB test D. C test 62. And ITU-T specification code that deals with the telephone circuits. A. X series B. T series C. V series D. I series 63. What digital carrier transmits a digital signal at 274.176 Mbps? A. T1 B. T3 C. T2

D. T4 64. What signal-to-noise ratio is required for satisfactory television reception? A. 10 dB B. 30 dB C. 40 dB D. 20 dB 65. How many telephone channels are there in AT 2 line? A. 50 B. 90 C. 83 D. 96 66. What optical source radiates light uniformly in all directions? A. Isotropic source B. Lambertian source C. Voltage source D. Ideal source 67. What is the spectrum of stereophonic FM signal? A. 19 to 38 kHz B. 30 to 53 kHz C. 59.5 to 74.5 kHz D. 88 to 108 MHz 68. What is the required quality factor for an SSB filter with the following data: center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB and the separation between sidebands= 200 Hz? A. 1,250 B. 12,500 C. 125,000 D. 25,000 69. What do you call the reflection of a part of incident light at the interface of two media that have different refractive indices? A. Snell’s reflection B. Fresnel reflection C. Lambertian reflection D. Huygen’s reflection

70. Which conference in the ITU-structure does the telecommunication standardization bureau report? A. World telecommunication standardization conference B. ITU-development sector C. Radio regulation board D. The secretary general 71. What region around a broadcasting transmitter in which satisfactory reception of broadcasting signal is not obtained? A. Fringe area B. Primary are C. Secondary area D. Tertiary area 72. What do you call the random noise seen on radar display screen? A. Impulse noise B. Atmospheric noise C. Grass D. Johnson noise 73. Which of the following antennas receives signals equally well from all directions in a horizontal plane? A. Hetz antenna B. Vertical Marconi antenna C. Yagi antenna D. Helical antenna 74. Where is the brightness control located in a TV? A. The audio section B. The video section C. The grid-cathode circuit D. The front panel 75. What is the term used in telephony and telegraphy for irregular disturbing radiation due to various causes and in a particular produced by arc transmitters causing a rushing sound in receiving telephones? A. Fax tone B. Mush C. Hiss

D. Crosstalk 76. What device in a waveguide system used for stopping or diverting electromagnetic wave as desired? A. Mechanical switch B. Electric switch C. Push-button switch D. Waveguide switch 77. What is the maximum power that can be obtained from a microwave tube at 10 GHz? A. 500 W B. 10 W C. 50 W D. 20 W 78. What do you call a cable consisting of twisted pairs of conductors, each separately insulated? A. Microstrip line B. Strip line C. Quad D. Coaxial cable 79. What mixer type has the lowest spurious signals? A. Double-balanced B. Single-balanced C. Super-heterodyner D. Heterodyner 80. What are the electromagnetic radiations of wavelengths less than 300 angstroms? A. X-rays B. Ultraviolet rays C. Infrared D. Microwaves 81. What is known as the alignment of the three color guns to a common point? A. Confetti B. Divergence C. Convergence D. Synchronization

82. What is the department order that governs commercial radio operator? A. Department Order No. 5 B. Department Order No. 23 C. Department Order No. 88 D. Department Order No. 44 83. The computer which initiates information transfer A. Master B. Station C. Slave D. Mainframe 84. Which of the following antennas require good grounding? A. Yagi antenna B. Hertz antenna C. Marconi antenna D. Isotropic antenna 85. Which circuit detects frequency modulated signal? A. Modulator B. Discriminator C. Demodulator D. Modem 86. What synchronization is provided so that the start and end of message is identified? A. Carrier B. Character C. Bit D. Clock 87. A form of regenerative repeater for transmitting signals over a long cable received through a relay in a clearer form. A. Active generator B. Active repeater C. Interpolator D. Audio generator 88. What is the minimum propagation delay of a geostationary satellite? A. 278 ms B. 239 ms

C. 300 ms D. 600 ms 89. In measuring crosstalk using dBx unit the reference power is A. 1 mW B. 1 W C. 1 pW D. 6 mW 90. A spot on the sun’s visible surface where the magnetic flux lines converge? A. Sunspot B. Filament C. Solar spot D. Prominence 91. ______ is a slow moving large mass of plasma on the sun’s surface. A. Filament B. Solar flare C. Prominence D. Proton flare 92. ______ is slow moving “cord-like” mass of plasma across the sun’s surface. A. Filament B. Solar flare C. Prominence D. Solar spot 93. At what particular wavelength is solar flux measured? A. 10.7 mm band B. 10.7 m band C. 10.7 cm band D. 10.7 nm band 94. What is the approximate intensity of the magnetic field at the earth’s surface? A. 32,000 nT B. 62,000 nT C. 32,000 µT D. 62,000 µT 95. What is the intensity of the magnetic field at the earth’s north pole?

A. B. C. D.

32,000 nT 62,000 nT 32,000 µT 62,000 µT

96. What do you call a satellite weighing less than 1 kg? A. Nanosat B. Picosat C. Femtosat D. Microsat 97. The first creature in space was carried by which of the following spacecrafts in November 3, 1957? A. Sputnik 1 B. Sputnik 3 C. Sputnik 2 D. Explorer 1 98. The wireless evolution is achieved through the GSM family of wireless technology platforms which include but except one of the following. Which one is NOT a member of the GSM family? A. GSM B. EDGE C. GPRS D. CDMA 99. Which of the following is an enhancement of GSM including the GPRS? A. 1G B. 2.5G C. 2G D. 3G 100. A low power, short range wireless technology designed to provide a replacement for serial cables is called ______. A. WAP B. GPRS C. Bluetooth D. EDGE

Noise Chapter 4 (3001 Questions in Communications Engineering-EXCEL REVIEW CENTER) 1. What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes? A. Wander B. Jitter C. Hits D. Singing 2. What theorem sets a limit on the maximum capacity of a channel with a given noise level? A. Nyquist theorem B. Hartley law C. Shannon-Hartley theorem D. Shannon theorem 3. Quantizing noise occurs in A. PCM B. PLM C. PDM D. PAM 4. Noise always affects the signal in a communications systems at the ________. A. transmitter B. channel C. information source D. destination 5. _________ is the random and unpredictable electric signals from natural causes, both internal and external to the system. A. Interference B. Attenuation C. Distortion D. Noise 6. Noise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band. A. Gaussian noise B. Whiter noise C. Thermal noise D. All of the above 7. Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder

D. Binary coding techniques 8. A particular circuit that rids FM of noise A. Detector B. Discriminator C. Phase Shifter D. Limiter 9. What is the reference noise temperature in degrees Celsius? A. 17 B. 273 C. 25 D. 30 10. Unwanted radio signal on assigned frequency. A. Splatter B. RFI C. Noise D. EMI 11. What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise 12. _________ is measured on a circuit when it is correctly terminated but does not have any traffic. A. White noise B. Galactic noise C. Impulse noise D. Atmospheric noise 13. Which standard recommends crosstalk limits? A. CCIT G.152 B. CCIT G.150 C. CCIT G.151 D. CCIT G.161 14. Which standard is utilized in intermodulation noise rates on PCM audio channels? A. CCIT Rec. G.151 B. CCIT Rec. G.172 C. CCIT Rec. G.190 D. CCIT Rec. G.190 15. What is the reference frequency of CCIT phosphomeric noise measurement? A. 800 Hz

B. 1000 Hz C. 1500 Hz D. 3400 Hz 16. Reference temperature use in noise analysis A. 75 K B. 250 K C. 290 K D. 300 K 17. Which noise is produced by lighting discharges in thunderstorms? A. White noise B. Extraterrestrial noise C. Industrial noise D. Atmospheric noise 18. Man-made noise is usually from _______. A. transmission over power lines and by ground wave B. sky-wave C. space-wave D. troposphere 19. nif stands for A. Non-intrinsic figure B. Noise improvement factor C. Narrow intermediate frequency D. Noise interference figure 20. Industrial noise frequency is between _____. A. 0 to 10 KHz B. 160 MHz to 200 MHz C. 15 to 160 MHz D. 200 to 3000 MHz 21. External noise fields are measured in terms of _______. A. rms values B. dc values C. average values D. peak values 22. Form of interference caused by rain or dust storms. A. Precipitation static B. Shot-noise C. Galactic noise D. Impulse noise 23. At 17˚ C, the noise voltage generated by 5kΩ resistor, operating over a bandwidth of 20KHz is

A. 1.3 nV B. 1.3 µV C. 1.3 pV D. 1.3 mV 24. ________ is an electric noise produced by thermal agitation of electrons in conductor and semiconductor. A. External noise B. Internal noise C. Thermal noise D. Flicker 25. Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? A. 5.23 dB B. 14.77dB C. 30 dB D. 40 dB 26. The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? A. 11.59 dB B. 11.23 dB C. 10.79 dB D. 10.5 dB 27. Is the interference coming from other communications channels? A. Jitter B. Crosstalk C. RFI D. EMI 28. What is the reference noise level? A. 10 pW B. 0 dBm C. 1mW D. -90 dBm 29. What is the unit of noise power of psophometer? A. pWp B. dBa C. dBm D. dBrn 30. A large emission of hydrogen from the sun that affects communications. A. Solar flare B. Cosmic disturbance

C. Ballistic disturbance D. Solar noise 31. Atmospheric noise is known as _______noise. A. static B. cosmic C. solar D. lunar 32. Standard design reference for environmental noise temperature. A. 300 K B. 290 K C. 32 ˚F D. 212˚F 33. Absolute temperature in Kelvin. A. ˚C +273 B. ˚C+75 C. ˚C+19 D. ˚C +290 34. If bandwidth is doubled, the signal power is _________. A. not changed B. quadrupled C. tripled D. doubled 35. Name one or more sources of noise bearing on electronic communications. A. Steam boiler B. Galaxies C. Internal combustion engine D. Both B and C 36. The transmitter technique adopted to reduce the noise effect of the preceding question is called A. noise masking B. anitnoise C. noise killing D. preemphasis 37. Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high 38. Atmospheric noise or static is not a great problem

A. at frequencies below 20 MHz B. at frequencies below 5 MHz C. at frequencies above 30 MHz D. at frequencies above 1 MHz 39. What is the proper procedure for suppressing electrical noise in a mobile station? A. Apply shielding and filtering where necessary B. Insulate a all plain sheet metal surfaces from each other C. Apply anti-static spray liberally to all nonmetallic D. Install filter capacitors in series with all dc wiring 40. Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver? A. Man-made noise B. In the atmosphere C. In the receiver front end D. In the ionosphere 41. The difference between signal strength at a given point and a reference level is________. A. power B. dBm C. level D. ratio 42. Interfering effect of noise, C message weighted, is _________. A. dBa B. dBm C. dBmc D. dB 43. F1A weighting refers to ___________. A. -90 dBm B. dBrnc0 C. dBrnc D. F1A handset 44. Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point is equal to ______ dBrnc0. A. 58 B. 51 C. 65 D. 27 45. Reading a 58 dBrn, at a +7 test point is equal to ________ dBa0. A. 26 B. 65 C. 51

D. 46 46. A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals _____ dB of crosstalk coupling. A. 20 B. 30 C. 60 D. 25 47. Power is __________. A. actual amount of power reference to 1mW B. logarithmic ratio of two powers C. definite amount of energy per time period D. current flow per time period 48. 15 dBa F1A weighted, equals ___________. A. -90 dBm B. -82 dBm C. -85 dBm D. -70 dBm 49. You are measuring noise in a voice channel with a Lenkurt 601A, F1A weighting network and a flat meter. Your meter reads -47dBm. What is this reading in dBa? A. 77 dBa B. 35 dBa C. 38 dBa D. 32 dBa 50. You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57dBm. This is ________dBa0. A. 20 B. 15 C. 25 D. 17 51. You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -59 dBm. This is _________ dBa0. A. 24 B. 12 C. 23 D. 32 52. A measurement of -75 dBm, C-message weighted, would be _________ dBrnc. A. 8 B. 7 C. 9 D. 15

53. Your Western Electric 3A test set meter reading is -23 dBm at at test point level of -8 dB. This is ______ dBrnc0. A. 75 B. 29 C. 30 D. 31 54. At what power level does a 1 KHz tone cause zero interference (144 weighted)? A. 90 dB B. 90 dBm C. -90 dBm D. -90 dBm 55. Reference noise is ___________. A. a 1000 Hz, -90 dBm tone B. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone C. a noise that creates zero dBrn in a voice channel D. B and C above 56. A practical dBrn measurement will almost always in a _______ number. A. positive B. negative C. imaginary D. fractional 57. What is the reference level for noise measurement, F1A weighted? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm 58. What is the reference tone level for dBrn? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm 59. What is the reference tone level for dBa? A. -90 dBm B. -82 dBm C. -67 dBm D. -85 dBm 60. Atmospheric noise becomes less severe at frequencies A. above 30 MHz B. below 30 MHz C. above 3000 kHz

D. below 3000kHz 61. Indicate the noise whose sources are in category different from that of the other three? A. Solar noise B. Cosmic noise C. Atmospheric noise D. Galactic noise 62. Indicate the false statement. A. Industrial noise is usually of the impulse type B. Static is caused by lightning discharges in thunderstorms and other natural electric disturbances occurring in the atmosphere C. Distant stars are another source of man-made noise D. Flourescent lights are another source of man-made noise 63. Which of the following is not a source of industrial noise? A. Automobile ignition B. Sun C. Electric Motors D. Leakage from high voltage line 64. Indicate the false statement A. The noise generated in a resistance or the resistive component of any impedance is random. B. Random noise power is proportional to the bandwidth over which is measured C. A random voltage across the resistor does not exist D. All formula referring to random noise are applicable only to the value of such noise. 65. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore. A. halved B. quadrupled C. doubled D. unchanged 66. Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type. 67. An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? A. 40 µV B. 4.0 µV C. 400 µV

D. 4.0 mV 68. The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, respectively. Calculate the equivalent input-noise resistance of this two stage amplifier. A. 2,518 kΩ B. 2,518 Ω C. 251.8 Ω D. 12,518 Ω 69. The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to 5kHz, its gain remaining constant, what does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV 70. The front-end of a television receiver, having a bandwidth of 7Mhz, and operating at a temperature of 27˚C , consists of an amplifier having a gain of 15 followed by a mixer whose gain is 20. The amplifier has a 300 Ω input resistor and a shot noise equivalent resistance of 500Ω; for the mixer, these values are 2.2kΩ and 13.5kΩ respectively, and the load resistance of the mixer is 470 kΩ. Calculate the equivalent noise resistance for this television receiver. A. 8760 Ω B. 875Ω C. 8.76Ω D. 0.876Ω 71. One of the following is not a useful quantity for comparing the noise performance receivers. A. Input noise voltage B. Equivalent noise resistance C. Noise temperature D. Noise figure. 72. Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or load resistor B. noise factor expressed in decibels C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals

D. S/N of an ideal system divided by S/N at the output of the receiver or amplifier under test, both working at the same temperature over the same bandwidth and fed from the same source 73. Calculated the noise figure of the amplifier whose Req equals 2518Ω (RT=600Ω) if its driven by a generator whose output impedance is 50Ω. A. 39.4 B. 3.94 C. 394 D. 0.394 74. Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1.0MHz and the temperature is 20˚C, and that the receiver is connected to an antenna with an impedance of 75Ω. A. 30.3 B. 3.03 C. 303 D. .303 75. A receiver connected to an antenna whose resistance is 50 Ω has an equivalent noise resistance of 30Ω. Calculate its equivalent noise temperature if the noise figure is equal to 1.6. A. 17.4 K B. 174K C. 1.74K D. 17K 76. Most internal noise comes from A. Shot noise B. Transit-time noise C. Thermal agitation D. Skin effect 77. Which of the following is not a source of external noise? A. Thermal agitation B. Auto ignition C. The sun D. Fluorescent lights 78. Noise can be reduced by A. widening the bandwidth B. narrowing the bandwidth C. increasing temperature D. increasing transistor current levels 79. Noise at the input to the receiver can be as high as several

A. microvolts B. milivolts C. volts D. kilo volts 80. Which circuit contributes most of the noise in a receiver? A. IF amplifier B. Demodulator C. AF amplifier D. Mixer 81. Which noise figure represents the lowest noise in receiver? A. 1.6 dB B. 2.1 dB C. 2.7 dB D. 3.4 dB 82. The transistor with the lowest noise figure in the microwave region is a A. MOSFET B. Dual-gate MOSFET C. JFET D. MESFET 83. What is the noise voltage across a 300Ω input resistance to a TV set with a 6MHz bandwidth and temperature of 30˚C? A. 2.3 µV B. 3.8µV C. 5.5µV D. 5.4µV 84. Which of the following types of noise becomes of great importance at frequencies? A. Shot noise B. Random noise C. Impulse noise D. Transit-time noise 85. The solar cycle repeats the period of great electrical disturbance approximately every A. 11 years B. 10 years C. 9 years D. 8 years 86. The square of the thermal noise voltage generated by a resistor is proportional to A. its resistance B. its temperature C. the bandwidth over which it is measured D. All of the above

87. Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. A. Quantizing noise B. Thermal noise C. Impulse noise D. Crosstalk 88. Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk 89. Noise that occurs via capacitive or inductive coupling in a cable. A. Crosstalk B. Quantizing noise C. Reference noise D. Tone interference 90. Sources of impulse noise induced in communication channels. A. Erroneous digital coding bit caused by an error on a transmission facility B. Transients due to relay operation C. Crosstalk from dc signaling systems D. All of these 91. Crosstalk due to incomplete suppression of sidebands or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as A. Impulse noise B. Thermal noise C. Quantizing noise D. Miscellaneous noise 92. ___________ is device that measures the internal open circuit voltage of an equivalent noise generator having an impedance of 600Ω and delivering noise power to a 600 Ω load. A. Psophometer B. Barometer C. Reflectometer D. Voltmeter 93. External noise originating outside the solar system A. Cosmic noise B. Solar noise C. Thermal noise D. Lunar noise 94. A noise whose source is within the solar system.

A. Solar noise B. Thermal noise C. Cosmic noise D. Johnson Noise 95. The total noise power present in a 1-Hz bandwidth . A. Noise density B. Noise figure C. Noise limit D. Noise intensity 96. Which of the following is not a way of minimizing if not eliminating noise? A. Use redundancy B. Increase transmitted power C. Reduce signaling rate D. Increase channel bandwidth 97. What is the primary cause of atmospheric noise? A. Thunderstorm B. Lightning C. Thunderstorm and lightning D. Weather condition 98. What do you call the noise coming from the sun and stars? A. Black-body noise B. Space noise C. Galactic noise D. All of these 99. The major cause of atmospheric or static noise are A. Thunderstorms B. Airplanes C. Meteor showers D. All of these 100. Which of the following low noise transistors is commonly used at microwave frequencies? A. MOSFET B. GASFET C. MESFET D. JFET

Satellite Communications Chapter 10(3001 Questions in Communications EngineeringEXCEL REVIEW CENTER 1. Which of the following is the first active satellite? A. Echo I B. Telstar I C. Early Bird D. Sputnik I 2. Which of the following is the first commercial satellite? A. Early Bird B. Telstar C. Explorer D. Courier 3. What is the first passive satellite transponder? A. Sun B. Early Bird C. Score D. Moon 4. The first satellite to receive and transmit simultaneously A. Intelsat I B. Agila I C. Syncorn I D. Telstar I 5. A helical antenna is used for satellite tracking because of A. circular polarization B. maneuverability C. beamwidth D. gain 6. Repeaters inside communications satellites are known as A. Trancievers B. Transponders C. Transducers D. TWT 7. Considered as the unsolved problem in satellite system A. Coverage B. Cost C. Access D. Privacy 8. ___________ is a satellite that rotates around the earth in a low-altitude elliptical or circular pattern. A. Geosynchronous satellite

B. Nonsynchronous satellite C. Prograde satellite D. Retrograde satellite 9. Is the geographical representation of a satellite antenna radiation pattern A. Footprint B. Spot C. Earth D. Region 10. The smallest beam of a satellite antenna radiation pattern A. Zone beam B. Hemispheric beam C. Spot beam D. Global beam 11. A satellite beam that covers almost 42.4% of the earths surface. A. Zone beam B. Hemispheric beam C. Spot beam D. Global beam 12. What is the frequency range of C-band? A. 8.5 to 12.5 GHz B. 3.4 to 6.425 GHz C. 12.95 to 14.95 GHz D. 27.5 to 31 GHz 13. A satellite signal transmitted from a satellite transponder to earth’s station. A. Uplink B. Downlink C. Terrestrial D. Earthbound 14. Collects very weak signals from a broadcast satellite A. Helical antenna B. Satellite dish C. LNA D. TWT 15. What is a device that detects both vertically and horizontally polarized signals simultaneously? A. Orthomode transducer B. Crystal detector C. Optoisolator D. Isomode detector

16. _________ detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. A. Horn antenna B. LNA C. Satellite receiver D. Satellite dish 17. Is a loss of power of a satellite downlink signal due to earth’s atmosphere. A. Atmospheric loss B. Path loss C. Radiation loss D. RFI 18. What height must a satellite be placed above the surface of the earth in order for its rotation to be equal to earth’s rotation? A. 26,426.4 miles B. 27,426.4 miles C. 23,426.4 miles D. 22,426.4 miles 19. Point on the satellite obits closest to the earth. A. Apogee B. Perigee C. Prograde D. Zenith 20. The earth area covered by a satellite radio beam. A. Beamwidth B. Bandwidth C. Footprint D. Zone 21. What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band? A. 3500 MHz B. 4500 MHz C. 2225 MHz D. 2555 MHz 22. What kind of battery panels are used in some advance satellites A. Germanium based panels B. Silicon based panel C. Galium Phosphate solar panel array D. Galium Arsenide solar panel array 23. Satellite engine uses A. jet propulsion

B. ion propulsion system C. liquid fuel D. solar jet 24. A satellite batter has more power but lighter. A. Lithium B. Leclanche C. Hydrogen D. Magnesium 25. What kind of battery used by older satellites? A. Lithium B. Leclanche C. Hydrogen D. Magnesium 26. VSAT was made available in A. 1979 B. 1981 C. 1983 D. 1977 27. What band does VSAT first operate? A. L-band B. X-band C. C-band D. Ku-band 28. The first Philippine Mabuhay satellite has how many channels? A. 30 B. 24 C. 48 D. 50 29. The first Philippine Agila I will have how many transpoders. A. 36 B. 48 C. 24 D. 12 30. How may satellite orbital slots are requested by the Philippine Government from ITU? A. 2 B. 4 C. 6 D. 8 31. The location of AsiaSat I. A. 105.5˚East

B. 151.5˚East C. 115.5˚East D. 170.5˚East 32. AsiaSat I covers how many countries in Asia? A. 38 B. 10 C. 28 D. 15 33. The owner of AsiaSat 2 is A. Asia Satellite Telecommunications Company (ASTC) B. Japan Satellite System (JSAT) C. China Great Wall Industry Corporation D. Singapore Satellite Commision 34. What is the approximate path loss from satellite-to-earth station? A. 100 dB B. 150 dB C. 175 dB D. 200 dB 35. INTELSAT stands for A. Intel Satellite B. International Telephone Satellite C. International Telecommunications Satellite D. International Satellite 36. The frequency of Ku band for satellite communications. A. 6/4 GHz B. 14/11 GHz C. 12/14 GHz D. 4/8 GHz 37. A satellite cross-link means A. Earth-to-satellite link B. Satellite-to-earth link C. Satellite-to-satellite link D. None of these 38. Earth station uses what type of antenna A. Despun antenna B. Helical antenna C. Toroidal antenna D. Cassegrain antenna 39. What is the delay time for satellite transmission from earth transmitter to earth receiver? A. 0.5 s

B. 1.0 s C. 5 ms D. 0.25 ms 40. The bandwidth of C-band satellite frequency band in U.S. A. 500 GHz B. 1000 GHz C. 1000 MHz D. 500 MHz 41. The most common device used as an LNA is A. zener diode B. tunnel diode C. IMPATT D. Shockley diode 42. The radiation patterns of earth coverage antennas have a beamwidth of approxiamately A. 21˚ B. 5˚ C. 17˚ D. 35˚ 43. A mobile satellite array has usually how many elements? A. 6 B. 88 C. 12 D. 14 44. In a typical mobile satellite array antenna if three elements are activated, how many elements are deactivated? A. 3 B. 11 C. 5 D. 9 45. What circuit is responsible in activating and deactivating adjacent antenna elements in a mobile satellite array? A. Radial divider B. Divider/combiner C. Radial combiner D. Radial multiplexer 46. Most mobile satellite array uses ___________ in transforming 50 to 150 Ω impedance. A. stub B. balun C. quarter-wavelength transformer D. microstrip tapers.

47. The switching from one element to the other element in a typical mobile satellite array. A. Series B. Radial C. Matrix D. Shunt 48. A method of multiple accessing where a given RF channel bandwidth is divided inot smaller frequency band. A. CDMA B. ANIK-D C. TDMA D. FDMA 49. What is the delay time for satellite transmissions from earth transmitter to earth receiver? A. 0.5 s B. 1s C. 5 ms D. 0.25 s 50. As the height of a satellite orbit gets lower, the speed of the satellite _________. A. increases B. decreases C. remains the same D. None of the above 51. The main function of a communications satellite is a/ an A. repeater B. reflector C. beacon D. observation platform 52. The key electronic component in a communications satellite is the A. telemetry equipment B. on-board computer C. command and control system D. transponder 53. A circular orbit around the equator with a 24-h period is called a/an A. elliptical orbit B. geostationary orbit C. polar orbit D. transfer orbit 54. A satellite stay in orbit because the following two factors are balanced A. Satellite weight and speed B. Gravitational force and centrifugal force C. Centripetal force and speed

D. Satellite weight and the pull of the moon and sun 55. What is the height of a satellite in a synchronous equatorial orbit? A. 42000 mi B. 6800 mi C. 22,300 mi D. 35,860 mi 56. Most satellites operate in which frequency band? A. 30 to 300 MHz B. 300 MHz to 3 GHz C. 3 GHz to 30 GHz D. Above 300 GHz 57. The main power sources for a satellite are A. batteries B. solar cells C. fuel cells D. thermoelectric generators 58. The maximum height of an elliptical orbit is called the A. Perigee B. Apex C. Zenith D. Apogee 59. Batteries are used to power all satellite subsystems A. at all times B. only during emergencies C. during eclipse periods D. to give the solar arrays a rest 60. The satellite subsystem that monitors and controls the satellite is the A. propulsion subsystem B. power subsystem C. communications subsystem D. telemetry, tracking, and command subsystem 61. What is the basic technique used to stabilize a satellite? A. Gravity-forward motion balance B. Spin C. Thruster control D. Solar panel orientation 62. The jet thrusters are usually fired to A. maintain altitude B. put the satellite into the transfer orbit C. inject the satellite in the geosynchronous orbit

D. bring the satellite back to earth. 63. Most commercial satellite activity occurs in which band(s)? A. L B. C and Ku C. X D. S and P 64. How can multiple earth stations share a satellite on the same frequencies? A. Frequency reuse B. Multiplexing C. Mixing D. Frequency hopping 65. What is the typical bandwidth of a satellite band? A. 36 MHz B. 40 MHz C. 70 MHz D. 500 MHz 66. Which of the following is not usually a part of a transponder are defined by the A. LNA B. Mixer C. Modulator D. HPA 67. The satellite communications channels in a transponder are defined by the A. LNA B. bandpass filter C. mixer D. input signals 68. The HPAs in most satellite are A. TWTs B. Klystrons C. Vacuum tubes D. Magnetrons 69. The physical location of a satellite is determined by its A. distance from the earth B. latitude and longitude C. reference to the stars D. position relative to the sun 70. The receive GCE system in an earth station performs what function(s)? A. Modulation and multiplexing B. Up conversion C. Demodulation and demultiplexing

D. Down conversion 71. Which of the following types of HPA is not used in earth stations? A. TWT B. Transistor C. Klystron D. Magnetron 72. What is the common up-converter and down-converter IF? A. 36 MHz B. 40 MHz C. 70 MHz D. 500 MHz 73. What type of modulation is used on voice and video signals? A. AM B. FM C. SSB D. QPSK 74. What modulation is normally used with digital data? A. AM B. FM C. SSB D. QPSK 75. Which of the following is not a typical output from a GPS receiver? A. Latitude B. Speed C. Altitude D. Longitude 76. The total space loss of transmission and reception for two ground stations with uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3˚ and 7˚ A respectively is A. 403 dB B. 100 dB C. 20 dB D. 215 dB 77. The maximum propagation delay of a geostationary satellite is A. 278 ms B. 239 ms C. 300 ms D. 250 ms 78. The total propagation delay time from transmission to reception of signals from a ground transmitter to ground receiver with angle of elevation at 10 degrees respectively is

A. 273 ms B. 239 ms C. 275 ms D. 260 ms 79. A satellite which simply reflects the signal without further amplification A. Passive satellite B. Active satellite C. Geostationary satellite D. Domestic satellite 80. Essentially a satellite ___________ is a radio repeater in the sky A. transponder B. comparator C. duplexer D. billboard 81. Satellite the orbits in a circular pattern with an angular velocity equal to that of the earth A. Geostationary B. Early Bird I C. Syncorn I D. Stationary satellite 82. Satellite that provide services within a single country A. Domsat B. Comsat C. Regional D. Global 83. The round-trip propagation delay between two earth stations through a geosynchronous satellite is A. 500 to 600 ms B. 300 to 400 ms C. 600 to 700 ms D. 400 to 500 ms 84. The signal path from earth station satellite A. Uplink signal B. Reflected signal C. Incident signal D. Downlink signal 85. Designed to receive a signal from a transmitting station on the ground and retransmit it to a receiving station located elsewhere A. Communication satellite B. Repeater C. Relay station

D. Transponder 86. The signal path from satellite to earth-based receiver. A. Downlink signal B. Uplink signal C. Incident signal D. Reflected signal 87. A satellite position is measured by its __________ angle with respect to the horizon. A. elevation B. depression C. azimuth D. critical 88. The ________ angle measures the satellite position clockwise from the direction of true north. A. azimuth B. elevation C. depression D. critical 89. incidentally propose the geostationary scheme or orbit of the satellite in 1940s A. Arthur Clarke B. Carl Friedrich Gauss C. Samuel Morse D. Stephen Gray 90. When the satellite are spaced 4˚ of the 360˚ complete circle, how many parking spaces or orbit slots are available? A. 90 B. 85 C. 95 D. 80 91. The control routine necessary to keep the satellite in position is referred to as A. station keeping B. station tracking C. station monitoring D. station maintaining 92. Refers to the satellite orientation with respect to the earth A. Satellite altitude B. Satellite position C. Satellite location D. Satellite orbit 93. The first intelsat satellite that was launched in 1965 was named A. Early Bird I

B. Echo C. Telstar I D. Courier 94. The first satellite launched for a geosynchronous orbit but unfortunately lost during orbit injection A. Syncom I B. Telstar I C. Sputnik I D. Early Bird I 95. When the elevation angle of a geostationary satellite is 23˚ and the transmitting frequency is 3840 MHz, what is the free space loss in dB? A. 196 dB B. 200 dB C. 150 dB D. 100 dB 96. What is the propagation delay when a signal is transmitter by an earth station to a geosynchronous satellite about 38,500 km above earth’s equator and then received by the same earth station? A. 256 msec B. 128 msec C. 300 msec D. 400 msec 97. What is the free space attenuation of a satellite communications system operating at 36,000 km above the earth at 5.0 GHz? A. 198 dB B. 202 dB C. 142 dB D. 138 dB 98. Which of the following is the most common application of satellite? A. Surveillance B. Military application C. Communications D. Newscasting 99. Descending pass for a satellite means a pass from A. North to South B. South to North C. East to West D. West to East 100. Geostationary stationary satellites are located ___________ with respect to the equator. A. 0˚longitude

B. 0˚ latitude C. 90˚latitude D. 45 latitude˚

3001 Questions in Communications Engineering – EXCEL REVIEW CENTER Chapter 6 - Antennas 1. What is the polarization of a discone antenna? A. Vertical B. Horizontal C. Circular D. Spiral 2. If the antenna increases 3.3 times how much does the radiated power increase? A. 3.3 times B. 10.89 times C. 9.9 times D. 6.6 times 3. When speaking of antennas. ______ is a section which would be a complete antenna by itself. A. image B. top loading C. bay D. quarterwave 4. In what range of frequencies are most omnidirectional horizontally polarized antennas used? A. VHF, UHF B. VLF, LF C. SH, EHF D. MF, HF 5. If the current ratios of the two or more elements must be held 5% and the phase angle to 3° the antenna is called a A. end fire array B. critical phased array C. broadband array D. wideband array 6. A device that converts high frequency current into electromagnetic wave. A. Antenna B. Loudspeaker C. Microphone D. Transducer 7. Which is a non-resonant antenna? A. Rhombic antenna B. Folded dipole C. End-fire array D. Yagi-Uda antenna

8. Gain of a half-wave dipole antenna over isotropic. A. 2.15 dB B. 1.76 dB C. 1 dB D. 0dB 9. Very low signal strength in antenna. A. Minor lobes B. Null C. Antenna patterns D. Major lobes 10. What is the gain of the Hertzian dipole over isotropic antenna? A. 1.64 dB B. 2.15 dB C. 1.76 dB D. 1.55 dB 11. ______ is the measurement of a unilateral antenna properties of directivity A. Phase angle B. Antenna gain C. Beamwidth D. Bandwidth 12. In testing transmitter to prevent interfering with other stations, which type of antenna must be used? A. Void antenna B. Dummy antenna C. Hertzian antenna D. Isotropic antenna 13. The best solution to fading is _____. A. space diversity B. frequency diversity C. polarization diversity D. wavelength diversity 14. _____ is the amount of uncertainty in a system of symbols A. Bandwidth B. Enthalpy C. Entropy D. Quantum

15. If an antenna has a gain of 3 dB, it increases the output of the transmitter by A. 10,000 times B. 1000 times C. 100 times D. 1 million times 16. Top loading is used in an antenna in order to increase its ______. A. practical height B. beamwidth C. effective height D. input capacitance 17. A horizontal antenna is _____. A. vertically polarized B. horizontally polarized C. centrally polarized D. circularly polarized 18. All elements in a beam _____ antennas are in line A. collinear B. yagi C. broadside array D. log-periodic 19. Which does not use vertical polarization antenna? A. AM Broadcasting B. FM Broadcasting C. Mobile Communications D. Satellite Communications 20. Lightning rods must be mounted a top structure not less than ___ above the highest point. A. 10 cm B. 20 cm C. 30 cm D. 40 cm 21. _____ is an antenna with a number of half-wave antenna on it. A. Antenna array B. Tower C. Omni-directional D. Rhombic

22. Which antenna radiates an omnidirectional pattern in the horizontal plane with vertical polarization? A. Marconi antenna B. Discone antenna C. Horn antenna D. Helical antenna 23. An antenna with very high gain and very narrow beamwidth. A. Helical antenna B. Discone antenna C. Horn antenna D. Parabolic dish antenna 24. What determines antenna polarization? A. The frequency of the radiated wave B. The direction of the radiated wave C. The direction of the magnetic field vector D. The direction of the electric field vector 25. _____ is the horizontal pointing angle of an antenna A. Azimuth B. Angle of elevation C. Right angle D. Beamwidth 26. A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW. What is the gain in dB, obtained by the use if the reflector. (Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24 27. What is the estimated medium wind loading in the Philippines for antenna tower design? A. 300 kph B. 100 kph C. 200 kph D. 250 kph 28. Discone radiation pattern is ______. A. omnidirectional/vertical polarized B. unidirectional C. bidirectional D. figure of eight

29. _____ is an open-ended slot antenna A. Helical antenna B. Rhombic antenna C. Notch antenna D. Cassegrain antenna 30. Which antenna is a properly terminated? A. Marconi B. Rhombic C. Dipole D. Yagi-Uda 31. What is the radiation characteristic of a dipole antenna? A. Omnidirectional B. Bidirectional C. Unidirectional D. Hemispherical 32. What is the theoretical gain of a Hertzian dipole? A. 1.76 dB B. 2.15 dB C. 3 dB D. 0 dB 33. An antenna with unity gain A. Rhombic B. Half-wave dipole C. Isotropic D. Whip 34. How will you increase the gain of an antenna? A. By adding several antennas in parallel B. By focusing the radiated energy in one desired direction C. By making antenna rods thicker D. By making the antenna size larger 35. An antenna which is one-tenth wavelength long A. Hertzian dipole B. Loop antenna C. Marconi antenna D. Elementary doublet

36. What is the minimum number of turns a helix antenna must have? A. 3 B. 5 C. 4 D. 6 37. What is the gain of isotropic antenna? A. 10 B. 1 C. 10 D. 100 38. Which of the following improves antenna directivity? A. Driven element B. Reflector element C. Director element D. Parasitic element 39. The antenna radiates _____ polarized waves when the transmitter antenna is horizontally installed. A. Vertically B. negatively C. horizontally D. circularly 40. The length of a Marconi antenna to operate with 985 kHz is ______. A. 200 ft B. 500 ft C. 250 ft D. 999 ft 41. What is the front-to-back ratio of an antenna which radiates 500 watts in a northernly direction and 50 watts in a southernly direction? A. 25000 dB B. 10 dB C. 100 dB D. 20 dB 42. If 4 kW in antenna produces 50 μV/m in a receiving antenna, a 15 kW will produce _____. A. 200 μV/m B. 10 μV/m C. 100 μV/m D. 20 μV/m

43. If the radiated power increase 10.89 times, the antenna current increases by ______. A. 3.3 times B. 6.6 times C. 1.82 times D. 10.89 times 44. The frequency of operation of a dipole antenna cut to a length of 3.4 m. A. 88 MHz B. 44 MHz C. 22 MHz D. 11 MHz 45. Comparing the signal strength arriving at the driven element from the desired direction to the signal strength reaching the driver from the opposite direction. A. Directivity B. Sensitivity C. Beamwidth D. Front-to-back ratio 46. What is the capture area of a dipole operated at 75 MHz? A. 4 mm B. 2 m2 C. 2.088 m2 D. 4.088 m2 47. _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given direction. A. Efficiency B. Power C. Gain D. Polarization 48. Shortening effect of an antenna that makes it appear as if it were 5% longer. A. End effect B. Flywheel effect C. Skin effect D. Capture effect 49. Harmonic suppressor connected to an antenna. A. Low-pass filter B. High-pass filter C. M-derived filter D. Constant-K

50. A simple half-wavelength antenna radiates the strongest signal A. at 45 degrees to its axis B. parallel to its axis C. at right angles to its axis D. at 60 degrees to its axis 51. The current maximum in a Marconi antenna is found at A. the base of the antenna B. the center of the antenna C. some point between the base and the center of the antenna D. the top of the antenna 52. If an antenna is too short for the wavelength being used, the effective length can be increased by adding: A. capacitance in series B. inductance in series C. resistance in parallel D. resistance in series 53. Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? A. Elementary B. Real C. Isotropic D. Dummy 54. The power fed to a two-bay turnstile antenna is 100 watts. If the antenna has a 2 dB power gain, what is the effective radiated power? A. 317 watts B. 158 watts C. 200 watts D. 400 watts 55. What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at pitch of λ/4, used at 100 MHz? A. 16 B. 41.1 C. 31.4 D. 1.25 56. How is it possible to lower the resonant frequency of Hertz dipole antenna? A. By reducing the frequency at the transmitter B. By connecting a capacitor in series with the antenna C. By the connecting a resistor in series with the antenna D. By connecting an inductor in series with the antenna

57. Which of the following antennas receive signals in the horizontal plane equality well from all directions? A. Horizontal Hertz antenna B. Vertical loop antenna C. Vertical Yagi antenna D. A vertical antenna which is a quarter-wavelength long 58. If the length of a Hertz dipole is decreased A. its resonant frequency will be lowered its distributed inductance will be increased B. its distributed inductance will be decreased C. its resonant frequency will be increased D. its distributed capacitance between the antenna and ground will be increased. 59. A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, what is the antenna current at the feed-point? A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A 60. A one-quarter wavelength shunt-fed vertical Marconi antenna A. has maximum radiation in a vertical direction B. must have a horizontal receiving antenna for the best reception C. must use a receiving antenna for the best reception D. must have a vertical receiving antenna for the best reception 61. A shunt-fed quarter-wavelength Marconi antenna A. has maximum RF impedance to ground at its feedpoint B. has a current null at its feedpoint C. has a zero DC resistance to ground D. has zero RF resistance to ground 62. The parasitic element of an antenna system will A. decrease its directivity B. increase its directivity C. give the antenna unidirectional properties D. both B and C 63. If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency will A. increase B. depend on the velocity factor so the resonant frequency can either be increased or decreased C. will be unchanged D. decrease

64. What is the effect of adding a capacitor in series with an antenna? A. The antenna’s resonant frequency will increase B. The antenna’s resonant frequency will decrease C. The antenna will be physically 5% longer than its electrical length D. A capacitor is never added in series with an antenna 65. How does the electric field strength of a standard broadcast station vary with the distance from the antenna? A. The field strength of a standard broadcast station vary with the distance from the antenna B. The field strength is directly proportional to the distance from the antenna C. The field strength remains constant regardless of the distance from the antenna D. The field strength varies inversely as the distance from the antenna 66. Stacking elements in a transmitting antenna system A. increases the field strength at the receiving antenna B. increases the directivity of the transmitter antenna C. decrease the size of the lobe in the radiation pattern D. both A and B 67. A vertical loop antenna has a A. unidirectional radiation pattern in the horizontal plane B. unidirectional radiation pattern in the vertical plane C. omnidirectional radiation pattern in the horizontal plane D. a bidirectional radiation pattern in the horizontal plane 68. In order to get maximum radiation to all surrounding points in the horizontal plane, the antenna used is a A. vertical loop B. vertical quarter-wavelength rod C. array which includes parasitic elements D. a horizontal Hertz dipole 69. What is the electrical wavelength of a 500 MHz signal? A. 60 centimeters B. 6 meters C. 0.06 meter D. 60 meters 70. If the antenna current is doubled, the field strength at a particular position is A. doubled B. halved C. multiplied by a factor of four D. divided by a factor of four

71. The rhombic antenna is primarily used for A. ground wave propagation B. space wave propagation C. ionosphere scatter propagation D. sky wave propagation 72. What antenna radiates equally in all directions? A. Vertical antenna B. isotropic antenna C. Horizontal antenna D. Dipole antenna 73. Actual height of antenna should be at least A. one wavelength B. half wavelength C. quarter wavelength D. three-fourth wavelength 74. Which antenna is not properly terminated? A. Resonant B. Non-resonant C. Isotropic D. Whip 75. ______ is an antenna array which is highly directional at right angles to the plane of the array? A. Broadside array B. End-fire array C. Turnstile array D. Log-periodic array 76. The directivity pattern of an isotropic radiator is A. a figure-8 B. a sphere C. a unidirectional cardioid D. a parabola 77. An isotropic radiator is A. in the northern hemisphere B. an antenna high enough in the air C. an antenna whose directive pattern is substantially incredible D. a hypothetical, omnidirectional antenna

78. The purpose of stacking elements on an antenna. A. Sharper directional pattern B. increased gain C. Improved bandpass D. All of these 79. The advantage of using top loading in a shortened HF vertical antenna is A. lower quality factor B. greater structural strength C. higher losses D. improved radiation efficiency 80. Where are the voltage nodes in a half-wave antenna? A. At the ends B. Three-quarters of the way from the feed point toward the end C. One-half of the way from the feed point toward the end D. At the feed point 81. A theoretical reference antenna that provides a comparison for antenna measurements. A. Marconi antenna B. Isotropic radiator C. Yagi-Uda array D. Whip antenna 82. A Hertz antenna is operating on a frequency of 2182 kHz and consists of a horizontal wire that is hanged between two towers. What is the frequency of its third harmonic? A. 727 kHz B. 6546 kHz C. 436 kHz D. 6.546 kHz 83. In horizontal-dipole antenna, the polarization is A. in the vertical direction B. in the horizontal direction C. circular D. measured at the center of the antenna 84. Increasing the electrical length of an antenna means A. add an inductor in parallel B. add a capacitor in series C. add an inductor series D. add a resistor is series

85. Stacking antennas at various angles results in A. a more omnidirectional reception B. a more unidirectional reception C. a more omnidirectional reception D. an overall reception signal increase 86. What is driven element? A. Always the rearmost element B. Always the forward most element C. The element fed by the transmission line D. The element connected to the rotator 87. What is antenna bandwidth? A. Antenna length divided by the number of elements B. The angle between the half-power radiation points C. The angle formed between two imaginary lines drawn through D. The frequency range over which an antenna can be expected to operate satisfactorily 88. To lengthen an antenna electrically, add a A. resistor B. battery C. condult D. coil 89. What is the gain of an antenna over a half-wavelength dipole when it has 6 dB gain over an isotropic radiator? A. 6.0 dB B. 8.1 dB C. 3.9 dB D. 10.0 dB 90. What is the usual electrical length of a driven element in an HF beam antenna? A. ¼ wavelength B. ¾ wavelength C. ½ wavelength D. 1 wavelength 91. What happens to the bandwidth of an antenna as it is shortened through the use of loading coils? A. It is increased B. It is decreased C. No change occurs D. It becomes flat

92. To electrically decrease the length of an antenna. A. add an inductor in series B. add an inductor in parallel C. add a resistor in series D. add a capacitor in series 93. Strong interference from one particular station can be eliminated by the use of A. noise limiters B. squelch circuits C. negative feedback D. wave traps in the antenna circuitry 94. It is useful to refer to an isotropic radiator. A. when comparing the gains of directional antennas B. when testing a transmission line for standing wave ratio C. when (in the northern hemisphere) directing the transmission D. when using a dummy load to tune a transmitter 95. A disadvantage of using a trap antenna. A. It will radiate harmonics B. It can only be used for single-bad operation C. It is too sharply directional at lower frequencies D. It must be neutralized 96. The input terminal impedance at the center of a folded dipole antenna is A. 72 Ω B. 300 Ω C. 50 Ω D. 73 Ω 97. When a capacitor is connected in series with a Marconi antenna? A. Antenna open circuit stops transmission B. An inductor of equal value must be added C. No change occurs to antenna D. Antenna resonant frequency increases 98. Where are the current nodes in a half-wave antenna? A. At the ends B. At the center C. Three-quarters of the way from the feed point toward the end D. One-half of the way from the feed point toward the end

99. For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance? A. As low as possible on the vertical radiator B. Near the center of the vertical radiator C. As close to the transmitter as possible D. At a voltage node 100. The effect of adding parasitic elements of a Hertz dipole is to A. make the antenna more omnidirectional B. reduce its resonant frequency C. increase the antenna’s power gain D. All of these 101. Stacking antenna elements A. increases sensitivity to weak signals B. will suppress odd harmonics C. decrease signal to noise ratio D. increases selectivity 102. In the case if Marconi antenna, the actual length if the radiating element is A. one-half wavelength B. one-quarter wavelength C. one wavelength D. one-eight wavelength 103. The antenna efficiency of an HF grounded vertical antenna can be made comparable to that of a half-wave antenna A. By installing a good ground radial system B. By isolating the coax shield from ground C. By shortening the vertical D. By lengthening the vertical 104. An antenna “efficiency” is computed by using one of the following equations. A. Efficiency = (radiation resistance / transmission resistance) B. Efficiency = (total resistance / radiation resistance) x 100% C. Efficiency = (effective radiated power / transmitter output) x 100% D. Efficiency = (radiation resistance / total resistance) x 100% 105. Increasing the resonant frequency of an end-fed Marconi antenna can be done by A. adding a capacitor in series and reducing the physical length B. adding an inductor in series C. adding an inductor in series D. All of these

106. Factors that determine the radiation resistance of an antenna A. Transmission line length and height of antenna B. The location of the antenna with respect to nearby objects C. It is a constant for all antennas since it is physical D. Sunspot activity and the time of day 107. _____ is the angle between the half-power radiation points A. Critical angle B. Beamwidth C. Angle of elevation D. Azimuth 108. What is the ratio of the maximum radiation intensity to the average radiation intensity? A. Aperture gain B. Directivity gain C. Transmission gain D. Power gain 109. Good grounding is important for A. horizontal antennas B. broadside array antennas C. vertical antennas D. Yagi-Uda antennas 110. An ungrounded antenna near the ground A. acts as a single antenna of twice the height B. is unlikely to need an earth mat C. acts as antenna array D. must be horizontally polarized 111. One of the following is very useful as a multiband HF receiving antenna. A. Parabolic antenna B. Elementary doublet C. Log-periodic D. Square loop 112. Which of the following antennas is best excited from a waveguide? A. Biconical B. Horn C. Helical D. Discone

113. Indicate which of the following reasons for using metal counterpoise with antennas is false. A. Impossibly of a good ground connection B. Protection of personnel working underneath C. Provision of an earth for the antenna D. Rockiness of the ground itself 114. Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator 115. Which antenna is not a wideband? A. Discone B. Folded dipole C. Helical D. Marconi 116. One of the following is not a reason for the use of an earth mat A. impossibility of a good ground connection B. provision of an earth for the antenna C. protection of personnel working underneath D. improvement of the radiation pattern of the antenna 117. One of the following makes an antenna physically long but electrically short A. Adding L in series B. Adding C in series C. Top loading D. Both A and C 118. When antennas are closed to the ground, _______ polarization is ideal A. horizontally polarized B. vertically polarized C. circularly polarized D. both A and B 119. _____ is an antenna made up of a number of full wavelengths A. Elementary doublet B. Log-periodic C. Long wire D. Whip

120. Any energy which radiates in the form of radio waves, infrared waves, light waves, x-rays, etc. A. Radiant energy B. Electromagnetic C. Heat D. Ultraviolet 121. Which one is an antenna coupling unit? A. Coupler B. Diplexer C. Lecher wire D. Duplexer 122. _____ polarization is employed in AM broadcasting A. Horizontal B. Vertical C. Circular D. Omnidirectional 123. ______ polarization is employed in FM broadcasting A. Horizontal B. Vertical C. Circular D. Bidirectional 124. Which antenna is not grounded at one end? A. Hertz B. Marconi C. Dipole D. Whip 125. Which antenna does not use the ground? A. Marconi B. Yagi C. Hertz D. Rhombic

OPTICAL FIBER COMMUNICATIONS 1. Founded the wave theory of light a. Francesco Grimaldi b. Edward Appleton c. James Clerk Maxwell d. Christian Huygens

2. Proposed the use of clad glass fiber as a dielectric waveguide a. Karpon and Keck b. Karpon and Bockham c. Bockham and Kao d. Kao and Keck

3. Developed the first laser a. Charles Townes b. Theodore Maiman c. Gordon McKenzie d. Albert Einstein

4. The band of light wavelengths that are too long to be seen by the human eye a. Amber b. Visible c. Infrared d. Ultraviolet

5. The band of light wavelengths that are too short to be seen by the human eye a. Amber b. Visible c. Infrared d. Ultraviolet

6. Which color has the shortest wavelength of light? a. Red b. Yellow c. Blue

d. Green

7. What generates a light beam of a specific visible frequency? a. Laser b. Maser c. Infrared d. Flashlight

8. Which of the following materials is sensitive to light? a. Photoresist b. Photosensitive c. Light Sensitive d. Maser

9. The core of an optical fiber has a a. Lower refracted index than air b. Lower refractive index than the cladding c. Higher refractive index than the cladding d. Similar refractive index with the cladding

10. Is the different angle of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitted. a. Acceptance angle b. Modes c. Sensors d. Aperture

11. The loss in signal power as light travels down a fiber is called a. Dispersion b. Scattering c. Absorption d. Attenuation

12. The bandwidth of optical fiber

a. b. c. d.

900MHz 900PHz 900THz 900EHz

13. If a mirror is used to reflect light, the reflected light angle is ____ as the incident angle a. Smaller b. Larger c. The same d. Independent

14. What is a specific path the light takes in an optical fiber corresponding to a certain angle and number of reflection a. Mode b. Grade c. Numerical Aperture d. Dispersion

15. Is the width of the range of wavelengths emitted by the light source a. Bandwidth b. Chromatic Dispersion c. Spectral width d. Beamwidth

16. Which theory states that the light wave behaves as if it consists of many tiny particles? a. Huygen’s theory b. Wave theory of light c. Nyquist theory d. Quantum theory

17. Fiber optic cables operate at frequencies near a. 20MHz b. 200MHz c. 2GHz d. 800THz

18. When a beam of light enters one medium from another, which quantity will not change? a. Direction b. Speed c. Frequency d. Wavelength

19. Dispersion is used to describe the a. Splitting of white light into its component colors b. Propagation of light in straight lines c. Bending of a beam of light when it goes from one medium to another d. Bending of a beam light when it strikes a mirror

20. Luminance efficiency is minimum for a a. Fluorescent tube b. High wattage light bulb c. Mercury vapor lamp d. Low wattage light bulb

21. An object farther from a converging lens than its focal point always has a/an _____ image. a. Inverted b. The same in size c. Virtual d. Smaller size

22. An object nearer to a converging lens than its focal point always has a/an ______ image. a. Inverted b. The same in size c. Virtual d. Smaller size

23. The real image formed by a spherical mirror is ____ relative to its object a. Erect b. Inverted

c. Smaller d. Larger

24. The wavelength of light has no role in a. Diffraction b. Interference c. Polarization d. Reflection

25. Longitudinal waves do not exhibit a. Polarization b. Refraction c. Reflection d. Diffraction

26. ________ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. a. Material dispersion b. Wavelength dispersion c. Modal dispersion d. Delay dispersion

27. What is the average insertion loss of fusion splice in fiber optics? a. 0.09dB b. 0.9dB c. 0.19dB d. 0.009dB

28. What is the insertion loss of connector-type splices for a single mode fiber optics? a. 0.51dB b. 0.31dB c. 0.49dB d. 0.38dB

29. What is the lifetime of LEDs?

a. b. c. d.

200,000 minutes 200,000 hours 150,000 minutes 150,000 hours

30. What is the lifetime of ILDs? a. 50,000 hours b. 75,000 hours c. 100,000 hours d. 125,000 hours

31. Photodiodes used as fiber optic directors are a. Unbiased to generate a voltage same as a solar cell b. Forward bias c. Reversed bias d. Thermoelectrically cooled

32. What type of fiber has the highest modal dispersion? a. Step-index multimode b. Graded index multimode c. Step-index single mode d. Graded index mode

33. Laser light is ______ emission. a. Coherent b. Stimulated c. Spontaneous d. Coherent and stimulated

34. A dielectric waveguide for the propagation of electromagnetic energy at light frequencies a. Stripline b. Microstrip c. Laser beam d. Fiber optics

35. Is a non-coherent light source foe optical communications system. a. ILD b. LED c. APD

d. PIN Diode

36. Which type of laser is the simplest to modulate directly by changing its excitation? a. Semiconductor b. Ruby c. Helium-neon d. Neodymium-YAG

37. Which laser emits light in the visible range 400 to 700 nm? a. Argon-ion b. Nitrogen c. Carbon-dioxide d. Neodymium-YAG

38. Which is the proper measurement of average power emitted by a pulsed laser? a. Energy x time b. Pulse energy x repetition rate c. Pulse energy / repetition rate d. Peak power x pulse length 39. What is the photon energy for an infrared wave with frequency of 1012 Hz? a. 10.6 x 1034 joules b. 6.63 x 10-34 joules c. 6.63 x 10-22 joules d. 10.6 x 1022 joules

40. A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? a. 5 cm b. 10 cm c. 15 cm d. 20 cm

41. Which of the following factor does not harm laser efficiency? a. Atmospheric absorption b. Excitation energy not absorbed c. Problems in depopulating the lower laser level d. Inefficiency in populating the upper laser level

42. Which of the following contributes to the broadening of laser emission bandwidth? a. Doppler shift of moving atoms and molecules b. Amplification within the laser medium c. Coherence of the laser light d. Optical pumping of the laser transition

43. The first laser emitted a. Pulses of 694 nm red light b. A continuous red beam c. Pulses of white light from a helical flashlamp d. Spontaneous emission

44. What is the stage of the sand becoming a silicon? a. Liquid b. Gas c. Molten d. Hot

45. Which of the following is used as an optical transmitter on the Fiber Optical Communications? a. APD b. LSA diode c. PIN diode d. LED

46. Which of the following is used as an optical receiver in fiber optics communications a. APD b. Tunnel diode c. Laser diode d. LED

47. The numerical aperture of a fiber if the angle of acceptance is 15 degrees, is a. 017 b. 0.26 c. 0.50 d. 0.75

48. The inner portion of the fiber cable is called a. Cladding b. Coating

c. Inner conductor d. Core

49. Which type of laser is the simplest to modulate directly by changing its excitation? a. Semiconductor b. Ruby c. Helium-neon d. Neodymium-YAG

50. The laser frequency when the light has the wavelength 800 nm is a. 375 x 10^12 Hz b. 475 x 10^15 Hz c. 375 x 10^9 Hz d. 375 x 10^18 Hz

51. Which of the following is not a common application of fiber-optic cable? a. Computer networks b. Long-distance telephone systems c. Closed circuit TV d. Consumer TV

52. Total internal reflection takes place if the light ray strikes the interface at an angle with what relationship to the critical angle? a. Less than b. Grater than c. Equal to d. Zero

53. The operation of the fiber-optic cable is based on the principle of a. Refraction b. Reflection c. Dispersion d. Absorption

54. Which of the following is not a common type of fiber-optic cable? a. Single-mode step-index b. Multimode graded-index c. Single-mode graded-index d. Multimode step-index

55. Cable attenuation is usually expressed in terms of a. Loss per foot b. dB/km c. intensity per mile d. voltage drop per inch

56. Which of the cable length has the highest attenuation? a. 1 km b. 2 km c. 95 ft d. 5500 ft

57. The upper pulse rate and information carrying capacity of a cable is limited by a. Pulse shortening b. Attenuation c. Light leakage d. Modal dispersion

58. The core of a fiber optic cable is made of a. Air b. Glass c. Diamond d. Quartz

59. The core of a fiber optic is surrounded by a. Wire braid shield b. Kevlar c. Cladding d. Plastic insulation

60. The speed of light in plastic compared to the speed of light in air is a. Slower b. Faster c. The same d. Either lower or faster

61. Which of the following is not a major benefit of fiber-optic cable? a. Immunity from interference b. No electrical safety problems c. Excellent data security

d. Lower cost

62. The main benefit of light-wave communications over microwaves or any other communications media is a. Lower cost b. Better security c. Wider bandwidth d. Freedom from interference

63. Which of the following is not part of the optical spectrum? a. Infrafed b. Ultraviolet c. Visible color d. X-rays

64. The wavelength of visible light extends from a. 0.8 to 1.0 nm b. 400 to 750 nm c. 200 to 660 nm d. 700 to 1200 nm

65. The speed of light is a. 186,000 mi/h b. 300 mi/h c. 300,000 m/s d. 300,000,000 m/s

66. Refraction is the a. Bending of light waves b. Reflection of light waves c. Distortion of light waves d. Diffusion of light waves

67. The ratio of speed of light in air to the speed of light in another substance is called the a. Speed factor b. Index of reflection c. Index of refraction d. Dielectric constant

68. A popular light wavelength in fiber-optic cable is a. 0.7 um b. 1.3 um c. 1.5 um d. 1.8 um

69. Which type of fiber optic cable is most widely used? a. Single-mode step-index b. Multimode step-index c. Single-mode graded-index d. Multimode graded-index

70. Which type of fiber-optic cable is the best for very high speed data? a. Single-mode step-index b. Multimode step-index c. Single-mode graded-index d. Multimode graded-index

71. Which type of fiber-optic cable has the least modal dispersion? a. Single mode step-index b. Multimode step-index c. Single-mode graded-index d. Multimode graded-index

72. Which of the following is not a factor in cable light loss? a. Reflection b. Absorption c. Scattering d. Dispersion

73. A distance of 8 km is the same as a. 2.5 mi b. 5 mi c. 8 mi d. 12.9 mi

74. A fiber-optic cable has a loss of 15 dB/km. The attenuation in a cable, 100 ft long is a. 4.57 dB b. 9.3 dB c. 24 dB

d. 49.2 dB

75. Fiber-optic cables with attenuations of 1.8, 3.4, 5.9, and 18 dB are linked together. The total loss is a. 7.5 dB b. 19.8 dB c. 29.1 dB d. 650 dB

76. Which light emitter is preferred for high speed data in a fiber-optic system a. Incandescent b. LED c. Neon d. Laser

77. Most fiber-optic light sources emit light in which spectrum? a. Visible b. Infrared c. Ultraviolet d. X-ray

78. Both LEDs and ILDs operate correctly with a. Forward bias b. Reverse bias c. Neither A or B d. Either A or B

79. Single-frequency light is called a. Pure b. Intense c. Coherent d. Monochromatic

80. Laser light is very bright because it is a. Pure b. White c. Coherent d. Monochromatic

81. Which of the following is NOT a common light detector a. PIN photodiode b. Photovoltaic diode c. Photodiode d. Avalanche photodiode

82. Which of the following is the fastest light sensor a. PIN photodiode b. Photovoltaic diode c. Phototransistor d. Avalanche photodiode

83. Photodiodes operate property with a. Forward bias b. Reverse bias c. Neither A or B d. Either A or B

84. The product of the bit rate and distance of a fiber-optic system is 2 Gbits km/s. What is the maximum rate at 5 km? a. 100 Mbits/s b. 200 Mbits/s c. 400 Mbits/s d. 1000 Gbits/s

85. Which fiber-optic system is better? a. 3 repeaters b. 8 repeaters c. 11 repeaters d. 20 repeaters

86. An important requirement for successful transmission system using light a. Powerful, reliable light source b. Strong glass c. Reliable, high cost transmission medium d. Powerful regenerators

87. What is used to block light from a laser and let other light through a. Neutral density b. Color

c. Interference d. Spatial

88. ________ is a light that can be coherent a. Spontaneous emission b. Monochromatic and in-phase c. Narrow beam divergence d. Monochromatic

89. Coherence of laser light is important for _________ a. Light propagation b. Getting laser light to pass through air c. Drilling holes d. Holography

90. The ultrapure glass used to manufacture optical fibers is approximately ___pure a. 99.9 % b. 99.99 % c. 99.999% d. 99.9999%

91. In fiber optics, PCS stands for a. Plastic-clad-silica b. Polyethylene-clad-silica c. Personal carrier system d. Personal communication 92. How many longitudinal modes can fall within a laser’s gain bandwidth? a. 2 b. 5 c. 9 d. No fixed limit, dependent on bandwidth and mode spacing

93. _________ is the result of photons of light that are absorbed by the atoms of the glass core molecules a. Ion resonance absorption b. Ultraviolet absorption c. Infrared absorption d. Absorption loss

94. In fiber optics, SCS stands for a. Suppressed-clad-silicon b. Silicon base-class-silica c. Silica-clad-silica d. Serial-clad-silicon

95. Human laser was developed by A. Javen at Bell laboratory in a. 1960 b. 1962 c. 1963 d. 1964

96. What parameter of light detector determines the range or system length that can be achieved for a given wavelength? a. Transit time b. Spectral response c. Dark current d. Responsitivity

97. Dark current in light detectors is caused by a. Thermally generated carriers in the diode b. The absence of light input c. Small leakage current d. Its imperfection

98. What is the unit of responsitivity? a. Ampere/volt b. Ampere/watt c. Watt/ampere d. Volts/ampere

99. One of the following is not a characteristic of light detectors. a. Responsitivity b. Spectral response c. Transmit time d. Dispersion

100. What is the typical wavelength of light emitted from epitaxially grown LEDs? a. 840 nm

b. 490 nm c. 480 nm d. 940 nm

101. a. b. c. d.

SONET stands for System Optical Network Synchronous Optical Network Silica Optic Network System Optical Fiber Net

102. a. b. c. d.

Band loss is A reduction in transmitter power caused by earth’s surface curvature A reduction in strength of the signal caused by folded dipole bends An attenuation increase caused by bends radiating from the side of the fiber All of these

103. a. b. c. d.

Infrared range for fiber optics 400 – 700 nm 700 – 1200 nm 300 – 2000 nm 400 – 7000 nm

104. a. b. c. d.

Which of the following is a disadvantage for plastic fiber optics? Noise immunity Electric hazards Higher losses All of these

105. a. b. c. d.

OTDR stands for Optical Time Domain Reflectometer Optical Transmit Direction Return Optical Time Domain Time Regeneration Overtime Direct Reference

106. a. b. c. d.

Which of the following is determined by an OTDR? Distance to trouble Length of fiber Refractive index All of these

107. Under normal condition, a single fiber should not be used for a two-way communication mainly because of a. Loss b. Fading c. Noise d. Attenuation

108. a. b. c. d.

A single mode optical fiber has a core diameter of _____ nm. 0.1 0.01 0.2 0.05

109. a. b. c. d.

A step-index multimode optical fiber has a core diameter of _____ nm. 0.02 0.2 2 0.002

110. a. b. c. d.

The graded-index multimode optical fiber has a core diameter of _____ nm. 0.5 0.05 0.0005 5

111. a. b. c. d.

Which is not a possible cause of optical fiber loss? Impurities Glass attenuation Stepped index operation Microbending

112. The ratio of the speed of light in a vacuum and the speed of light in the material used. a. S/N ratio b. Refractive index c. Intermodal dispersion d. Monomode ratio

113.

Splicing fibers means

a. b. c. d.

Fusion Butt Glue Both fusion and butt

114. a. b. c. d.

An IC that represents a short distance one-way optical communications Optoisolator Insulator Multivibrator Optical IC

115. a. b. c. d.

When light strikes a flat polished end of a fiber, it produces a loss of 14 % 4% 10 % 1%

116. When light strikes a flat polished end of a fiber, the fiber loss produced can be reduced by a. Splicing b. Antireflection coating c. Insulation jacket d. All of these

117. a. b. c. d.

In fiber optics, higher-order mode refers to Cladding boundary at high angle Backscattering electromagnetic signals Diffracting signals All of these

118. a. b. c. d.

The following are the cause of light attenuation in fiber optics except Backscattering Absorption Refraction Microbends

119. Why are visible-light LEDs not used for fiber optics? a. It has high losses b. It has short wave

c. It has low attenuation d. It has weak signal

120. a. b. c. d.

Optical cable testers are used for Checking refractive index Light power out of a fiber Non-calibrated light into a fiber Checking maximum distance covered

121. a. b. c. d.

A function of an optic isolator Cancels reflective waves Amplifies signal transmitted Filters unnecessary signals All of these

122. a. b. c. d.

An increase in light intensity produces fast optic switching due to Increase in index of glass Amplification of optical signal High gain Photoconductivity

123. a. b. c. d.

Light traveling in optical fiber follows which of the following principles. Huygen’s principle Reflection theory Light theory Snell;s law

124. Optical fibers for telecommunications are typically about _____ mils thick and consists of a glass core, a glass cladding of lower index of refraction, and a protective coating a. 5 b. 6 c. 7 d. 8

125. a. b. c. d.

Material dispersion is caused by the Wavelength dependence of the index of refraction Wavelength independence of the index of refraction Dependence of the propagation constant on the mode number Independence of the propagation constant on the mode number

126. a. b. c. d.

Modal dispersion is caused by the Dependence of wavelength on index of refraction Dependence of propagation constant on index of refraction Dependence of the propagation constant on the wavelength Dependence of the propagation constant on the mode number

127. a. b. c. d.

The dominant loss mechanisms in silica fiber are Absorption and radiation losses Absorption and Rayleigh scattering Coupling and radiation losses Radiation and modal dispersion

128. a. b. c. d.

The bandwidth of a fiber is limited by Mode Wavelength Dispersion Frequency

129. a. b. c. d.

Fiber bandwidth is generally specified as the Product of the bandwidth and distance Sum of the bandwidth and distance Difference of the bandwidth and distance Quotient of bandwidth and distance

130. The _____ of a detector is the fraction of incident photons that produce a photoelectron or electron-hole pair a. Responsitivity b. Photon efficiency c. Aperture d. Quantum efficiency

131. a. b. c. d.

132.

In solid-state optical detectors, the excited charge is transported in the solid by Holes and protons Holes and electrons Anion and cation Protons and photons

One of the following is not a solid-state optical detector

a. b. c. d.

APD PIN PMT Phototransistors

133. Optical detectors are square-law devices because they respond to _____ rather than amplitude a. Intensity b. Light c. Density d. Photon

134. The _____ is equal to the number of electrons emitted per second times the electron charge a. Intensity b. Optical power c. Photocurrent d. Responsitivity

135. a. b. c. d.

Which optical detector is used when high sensitivity and bandwidth are required? PMT APD PIN Phototransistor

136. a. b. c. d.

What is the average loss in fiber splice? 0.10 dB 0.15 dB 0.20 dB 0.25 dB

137. a. b. c. d.

Which of the following colors is not found in the visible light wave spectrum? Red White Orange Yellow

138. What is the frequency limit of an optical fiber? a. 20 GHz b. 30 GHz

c. 40 GHz d. 50 GHz

139. a. b. c. d.

The mechanical splice attenuation loss is _____ dB or less 0.1 0.01 0.001 1

140. a. b. c. d.

_____ is applied to protect core and cladding of the fiber Insulation Fiber insulation Silica Polymer jacket

141. a. b. c. d.

The energy of the photon is Directly proportional to its bandwidth Directly proportional to the Planck’s constant Directly proportional to Boltzmann’s constant Inversely proportional to the Planck’s constant

142. a. b. c. d.

Refractive index of glass 1.0 1.2 1.4 1.5

143. a. b. c. d.

1.0 1.4 1.8 2.0

144. a. b. c. d.

What is the unit of light wavelength? Micrometer Angstroms Mils Fathom

Refractive index of diamond

145. a. b. c. d.

How much is the power loss of the fusion splice? 0.1 dB or less 0.01 dB or less 1 dB or less 10 dB or less

146. a. b. c. d.

Used to test a fiber optics splice Spectrum analyzer Oscilloscope Optical power meter Field strength meter

147. a. b. c. d.

A coupler which consists of a series of lenses and a partly reflective surface Beam-splitting coupler Reflective star coupler Fused coupler None of these

148. a. b. c. d.

Reflections in many directions Diffuse reflection Diffraction Scattering Dispersion

149. a. b. c. d.

Commonly used electro-optic crystal for polarization modulation Lithium Niobate Tourmaline Sodium Chlorate Sphalerite

150. a. b. c. d.

Which modulation methods are the most widely used in optical systems? Phase and frequency modulations Polarization modulation and phase modulation Intensity modulation and phase modulation Intensity modulation and polarization modulation

BROADCASTING

1. Which of the following is the first component of any MATV system to receive broadcast signals? a. Filter b. LNA c. RF amplifier d. Antenna

2. Is the most common technique where apartment house, hotels, schools, condominiums, and multi-unit buildings distribute TV and FM signals to a number of receivers, using a single head-end. a. CCTV b. CATV c. MATV d. Antenna

3. TV channel 2, 4 and 5 belong to a. Low band UHF b. High band VHF c. Mid band UHF d. Low band VHF

4. A mechanism or device which enables the TV camera to move in lateral and tilting motion a. Panning device b. Scanner c. Tilting d. Pan/tilt device

5. Which of the following is a solid state imaging device? a. VIDICON b. ICONOSCOPE c. Charge couple device d. CCTV

6. What class of TV camera lens used to cover short distances? a. Normal b. Wide angle c. Telephoto

d. Zoom

7. What class of TV camera lens used to cover long distances? a. Normal b. Wide angle c. Telephoto d. Zoom

8. What is the local oscillator frequency in commercial AM broadcast if it is equal to 455 kHz? a. 0 to 1500 kHz b. 0 to 455 kHz c. 540 to 1600 kHz d. 955 to 2055 kHz

9. What is the allowable deviation ratio of commercial FM broadcast? a. 20 b. 75 c. 5 d. 25

10. The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila is a. 5 kW b. 10 kW c. 15 kW d. 20 kW

11. KBP radio code mandates that station must provide a minimum of ___ minutes a. 30 b. 45 c. 50 d. 60

12. What is the chroma subcarrier signal frequency for color television? a. 3.8 MHz b. 6.8 MHz c. 7.8 MHz d. 8.8 MHz

13. What is the frequency tolerance of an FM Radio Broadcast station? a. ± 20000 Hz b. ± 20 Hz c. ± 200 Hz d. ± 2000 Hz

14. The minimum frequency separation between frequency of AM broadcasting station a. 9 kHz b. 18 kHz c. 36 kHz d. 72 kHz

15. The aspect ratio HDTV is a. 4:3 b. 18:5 c. 14:8 d. 16:9

16. A newscast is a distinct unit of a program with a minimum news content of _____ minute(s) excluding intro, extro, headline and commercial load a. 1 b. 2 c. 3 d. 4

17. In accordance with existing provision of law and the KBP rules and the regulations, all stations shall actively promote the growth ands the development of Filipino music by playing _____ OPM every clock hour. a. 1 b. 2 c. 3 d. 4

18. Commercial load for radio shall not exceed ____ minutes for a one-hour program outside Metro Manila a. 15 b. 20 c. 25

d. 30

19. Commercial load for radio shall not exceed _____ minutes for a one-hour program outside Metro Manila. a. 15 b. 16 c. 17 d. 20

20. Program interruption for airing of commercial in Metro Manila shall not exceed _____ breaks in every program hour a. 5 b. 6 c. 7 d. 8

21. Program interruption for the airing of commercial outside Metro Manila shall not exceed _____ breaks in every program hour a. 5 b. 6 c. 7 d. 8

22. For Metro manila, the classification of prime time blocks for FM shall be a. 6:00 AM to 8:00 PM b. 6:00 AM to 12:00 NN c. 6:00 AM to 6:00 PM d. 12:00 NN to 12:00 MN

23. For provincial station, the classification of prime time blocks for FM radio shall be a. 6:00 AM to 8:00 PM b. 6:00 AM to 12:00 NN c. 6:00 AM to 6:00 PM d. 12:00 NN to 12:00 MN

24. All airtime classifications shall be submitted to and subject for approval by the a. NTC b. KBP-SA c. DOTC d. CCITT

25. _____ is the time circulation for one horizontal trace a. 52 us b. 62 us c. 48 us d. 50 us

26. Listing of the date and time of events, programs, equipment, tests, malfunctions and corrections in communications system. a. Reporting b. Documentation c. Log d. File

27. Which of the following is not a low impedance microphone? a. Dynamic b. Velocity c. Condenser d. Crystal

28. Facsimile permits remote duplications of which of the following items? a. Map b. Pictures c. Printed page d. All of these

29. Television has a lot of features in common with a. FM stereo b. Telephone service c. Motion picture d. Magazine

30. The major component of the TV signal waveform is the a. Video b. Radar c. Stereo d. Antenna

31. For NTSC TV system, the image is scanned from a. Top to bottom b. Left to right

c. Right to left d. Choices A and B above

32. One completes NTSC scanning cycle called field consists of how many lines a. 500 b. 525 c. 625 d. 60

33. The field rate in the NTSC television system a. 30 Hz b. 120 Hz c. 60 Hz d. 15.75 Hz

34. What is the horizontal synchronous blanking pulse rate? a. 30 Hz b. 60 Hz c. 15.75Hz d. 120 Hz

35. What is the vertical blanking pulse rate? a. 30 Hz b. 60 Hz c. 15.75 Hz d. 120 Hz

36. The pulses riding on the vertical blanking pulse a. Equalizing (sync) pulses b. Serrated vertical sync pulses c. Black level pulses d. Choices A and B above

37. Television camera pickup tube is called a. Vidicon b. Image orthicon c. Plumbicon d. All of the above

38. The television picture tube magnetic fields can be used for a. Beam focusing b. Beam deflection c. Beam production d. Beam modulation

39. What is the purpose of an indirectly-heated cathode in a cathode ray tube? a. Beam focusing b. Beam deflection c. Beam production d. Beam modulation

40. Video modulation for television is a. Amplitude modulation b. Frequency modulation c. Vestigial sideband d. Both amplitude modulation and vestigial sideband

41. Audio modulation for television is a. Amplitude modulation b. Frequency modulation c. Vestigial sideband d. Both amplitude modulation and vestigial sideband

42. What is the maximum frequency deviation for audio modulation in TV transmission? a. 25 kHz b. 30 kHz c. 50 kHz d. 75 kHz

43. The video carrier and the audio carrier are separated by ____ MHz. a. 4.5 b. 5.5 c. 6.5 d. 7.5

44. In a practical image scanned at the NTSC rate, the spectrum will include components clustered at the fundamentals and harmonics of _____ kHz a. 15.75 b. 30

c. 12.25 d. 45.5

45. Brightness of an image is known as a. Radiance b. Chrominance c. Reflectance d. Luminance

46. The colors at the vertices of the color triangle are referred to as a. Primary b. White c. Desaturated d. All of the above

47. A color signal which originate in the camera itself with color television pickup? a. Red b. Green c. Blue d. All of these

48. What are the three separate signals derived from a matrix in a color TV transmitter? a. Y, I and Q b. P, D and Q c. M, N and O d. R, S and T

49. Range of a VHF television transmitter a. 54 – 98 MHz b. 54 – 216 MHz c. 54 – 128 MHz d. 54 – 166 MHz

50. Range of a UHF television transmitter a. 470 – 670 MHz b. 470 – 770 MHz c. 470 – 890 MHz d. 470 - 980 MHz

51. What is the approximate bandwidth occupied by the chrominance video signal for color TV? a. 0.8 MHz b. 1.8 MHz c. 8.1 MHz d. 1.6 MHz

52. The colors found around the perimeter of the color triangle are said to be a. Saturated b. Dark c. Light d. Monochrome

53. At what position on the color triangle will saturated yellow be located? a. Between red and blue b. Between red and green c. Between blue and green d. At the center

54. What is the phase difference between the I and Q color signal carriers? a. 0° b. 45° c. 60° d. 90°

55. _____ is the most effective filter for separating luminance and chrominance frequency components. a. Low pass b. Band pass c. Notch d. Comb

56. The chrominance processing circuits can be deactivated when monochrome broadcasts are received by the a. Color killer b. SAW filter c. NOT gate d. All of the above

57. What is the standard video level, in percent PEV, for blanking?

a. b. c. d.

25 % 0% 12.5 % 75 %

58. What is the percent video level, in percent PEV, for black? a. 0 % b. 25 % c. 12.5 % d. 70 %

59. What is the standard video level, in percent PEV, for white? a. 0 % b. 12.5 % c. 25 % d. 70 %

60. One should first perform _____ before a convergence setup is performed. a. Gray tracking b. Screen setting c. Alignment d. Degaussing

61. If there are too many harmonics, one should check the a. Coupling b. Tuning of circuits c. Shielding d. Any of these

62. In transmitter amplifier design, an even-order harmonics can be prevented or reduced by a. Using a push-pull amplifier b. Operating class C c. Operating class AB d. All of these

63. The vertical and horizontal pulses are separated at the a. Sync separator b. AFC c. High voltage

d. AGC

64. The reason why buffer stage is included in a transmitter is to a. Present a constant load to the oscillator stage b. Present a low impedance to the oscillator stage c. Stop the oscillator from generating parasitic oscillations d. All of these

65. Where is the operating position of a radio station? a. On the bridge b. At the control point c. At the location of the receiver d. At the location of the transmitter

66. The alignment of the three color guns to a common point is known as a. Blooming b. Confetti c. Demodulation d. Convergence

67. A _____ is equivalent to 525 scanning lines a. Field b. Frame c. Cycle d. Interface set

68. A _____ represents one set of 262 ½ scanning lines a. Field b. Frame c. Cycle d. Interface set

69. The number of scanning lines is _____ per second a. 14750 b. 15570 c. 15750 d. 16550

70. Picture frames are repeated at the rate of _____ per second

a. b. c. d.

25 30 40 50

71. Lack of raster is an indication of no a. AGC b. High voltage c. Video signal d. Television signal

72. The sound and video signals are separated at the _____ of the TV receiver a. IF stage b. Video amplifier c. Video detector d. Burst separator

73. The presence of color bars is an indication that there is a problem in the _____ circuit a. Horizontal b. Reactor c. Burst separator d. Chroma amplifier

74. Type of emission produced when a frequency modulated transmitter is modulated by a TV signal a. A3F b. F3F c. A3C d. F3C

75. What is emission A3F? a. RTTY b. SSB c. TV d. Modulated CW

76. What is emission F3F? a. Facsimile b. Modulated CW c. Television

d. RTTY 77. Cause of slow rising white “hum bars” is the television a. Pad filter b. Bad rectifier c. Bad picture tube d. High voltage transformer

78. Adjusting the _____ may eliminate color confetti a. Color chroma amplifier b. Color killer c. Color detector d. Color oscillator

79. Video signal amplitude determine the picture quality called a. Chrominance b. Brightness c. Contrast d. Luminance

80. Part of broadcast day from midnight to local sunrise a. Daytime b. Experimental c. Nighttime d. Dawntime

81. Part of broadcast day from local sunset to local sunrise a. Dawntime b. Nighttime c. Daytime d. Experimental

82. What causes snow in television? a. High Q in the tuned circuit b. Excessive gain c. Random noise in the signal d. Insufficient wave traps

83. Vestigial sideband is known as _____ type of emission

a. b. c. d.

CF3 C3F B8E A3E

84. Vestigial sideband modulation is commonly used in a. TV broadcasting b. Monaural broadcasting c. Stereo broadcasting d. HF point-to-point communications

85. Which of the following filters block FM radio band for TV channels (2 to 13)? a. High-pass filter b. Low-pass filter c. Band pass filter d. Band-reject filter

86. The FM broadcast band is from a. 535 to 1600 kHz b. 30 to 300 kHz c. 88 to 108 MHz d. 300 to 2000 MHz

87. The type of emission used by standard AM radio broadcast a. A5C b. A0 c. A3 d. F3

88. The standard AM radio broadcast belongs to which frequency band? a. MF b. HF c. VHF d. LF 89. When were UHF channels (14 – 83) of television added? a. 1902 b. 1945 c. 1947 d. 1952

90. When was colored TV standards established in the United States? a. 1904 b. 1945 c. 1953 d. 1960

91. What synchronizes the horizontal line of the TV picture tube? a. HFC b. HSC c. HAFC d. All of these

92. A measure of how well the receiver can respond to every weak signals/ a. Selectivity b. Sensitivity c. Fidelity d. Quality factor

93. What is the allowable frequency deviation of a commercial FM broadcast band? a. 15 kHz b. 75 kHz c. 5 kHz d. 100 kHz

94. The final amplifier of either FM or AM transmitter is operated as a. Class A b. Class B c. Class C d. Class D

95. Standard AM broadcasting use _____ for greater and efficient coverage a. Circular polarized wave antenna b. Horizontal polarized wave antenna c. Both vertical and horizontal polarized wave antenna d. Vertical polarized wave antenna

96. Receiver sensitivity means a. The frequency allocation of the system b. Input impedance of the receiver c. The ability of picking up weak signal

d. The power to deliver the information

97. The main functions of the RF amplifier in a superheterodyne receiver is to a. Provide improved tracking b. Permit better adjacent-channel rejection c. Improve the rejection of the image frequency d. All of these

98. Local oscillator of a broadcast receiver always tunes to a frequency higher than the incoming frequency in order a. To help the image frequency rejection b. To allow easy tracking c. To allow adequate frequency coverage without switching d. All of these

99. Type of filter used in TV receivers that separates the chroma signal from the colorplexed video signal but leaves intact the Y-component a. Comb filter b. Bandpass filter c. Color filter d. Low pass filter

100. a. b. c. d.

What is the first letter-symbol for emission of unmodulated carrier? A N H F

101. a. b. c. d.

The channel for cable TV frequency range of 5.75 to 11.75 MHz T-1 T-8 2 3

102. a. b. c. d.

The frequency range for cable TV channel T-13 23.75 – 29.75 MHz 60 – 66 MHz 41.75 – 47.55 MHz 5.75 – 11.75 MHz

103. a. b. c. d.

Channel 8 frequency range allocation in cable TV 54 – 60 MHz 66 – 72 MHz 180 – 186 MHz 204 – 210 MHz

104. The _____ of a television system is a measure of its ability to delineate picture detail a. Contrast b. Resolution c. Hue d. Pixels

105. CCIR standards for the internal exchange of programmes on film for television used a. Rec 265-6 b. Rec 407-4 c. Rec 408-5 d. Rec 450-1

106. a. b. c. d.

CCIR transmission standards for FM sound broadcasting at VHF Rec 601.2 Rec 501.2 Rec 500.4 Rec 450.1

107. ISO Rec 23 in 1976 is the standard for a. Recorded characteristics for magnetic sound records on full cost 16 mm motion picture film b. Projector usage of 16 mm motion picture films for direct front projector c. Camera usage of 35 mm motion picture film d. Camera usage of 16 mm motion picture film

108. International broadcasting (short wave) uses frequency between _____ accordance with international agreements a. 7012 and 26100 kHz b. 6409 and 26100 kHz c. 5950 and 26100 kHz d. 10950 and 26100 kHz

109. a. b. c. d.

Which of the following station below is a regional channel? Class I-A Class II-D Class III-B Class IV

110. a. b. c. d.

The permissible power in kW of station II-A during nighttime is 0.25 – 50 10 – 50 1–5 None of these

111. a. b. c. d.

The television frequency which are now allocated to the land mobile services 806 and 192 MHz 800 and 806 MHz 668 and 674 MHz 776 and 782 MHz

112. a. b. c. d.

Numerical frequency band designation of channel 9 488 – 494 MHz 530 – 536 MHz 632 – 638 MHz 186 – 192 MHz

113. a. b. c. d.

Cable TV systems originate from Germany Dallas, Texas Pennsylvania Japan

114. A term applied to third and higher order products, which can greatly degrade the performance of a system a. Composite triple beat b. Single dual mode c. Field strength d. Noise

115. A station similar to a translator station in terms of equipment and service area but is permitted to originate originate programming from virtually any source a. DME

b. LPTV c. HDTV d. ITFS

116. Three stations are licensed to eligible educational entities for the distribution of program material to students enrolled in instructional curricula a. Translator b. LPTV c. HDTV d. ITFS

117. a. b. c. d.

ITFS means International Television Frequency Standard Instructional Telephone Frequency Service Instructional Television Fixed Service International telecommunications Frequency Standard

118. a. b. c. d.

MDS means Multipoint Distribution Service Multipoint Digital Service Maritime Data Standards Multipoint Drop Standards

119. a. b. c. d.

Direct broadcast satellite based allocation 12.2 – 12.7 GHz downlink 17.3 – 17.8 GHz for uplink 3.7 – 4.2 GHz for downlink 12.2 – 12.7 GHz for downlink and 17.3 – 17.8 GHz for uplink

120. a. b. c. d.

What is the channel number of an FM station with 88.1 MHz carrier? 201 202 203 204

121. a. b. c. d.

What is the carrier frequency of an FM station with channel number of 300? 107.5 MHz 101.1 MHz 107.9 MHz 99.5 MHz

122. If an FM station has an effective radiated power of 100 kW then it is under what class? a. Class A b. Class B c. Class C d. Class D

123. as a. b. c. d.

The video signal amplitude determines the quality of the picture otherwise known

124. a. b. c. d.

_____ is defined as to “send out in all direction” Broadcast Announce Media All of these

125. a. b. c. d.

The ultimate Dolby surround system is the Dolby NR Dolby Prologic dBx hall matrix

Hue Luminance Chrominance Contrast

Microwave Communications

1. __________ is the progressive decrease of signal strength with increasing distance. A. B. C. D.

Radiation Attenuation Modulation Propagation

2. Calculate the effective earth’s radius if the surface refractivity is 301. A. B. C. D.

8493 km 8493 mmi 6370 km 6370 mi

3. If k-factor is greater than 1, the array beam is bent A. B. C. D.

Away from the earth towards the ionosphere, towards the earth towards the outer space

4. the antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from: A. B. C. D.

S = 2λR/L S = 3λR/L S = λR/RL S = λR/L where R = effective earth radius (m) and L = path length (m)

5. Rainfall is an important factor for fading of radio waves at frequencies above

A. B. C. D.

10 GHz 100 GHz 1 GHz 100 MHz

6. Theoretically electromagnetic radiation field strength varies in inverse proportion to the square of the distance, but when atmospheric attenuation effects and the absorption of the terrain are taken into account the attenuation can be as high as the inverse _______ power of the distance. A. B. C. D.

Third Fourth Fifth Sixth

7. What do you call an attenuation that occurs over many different wavelengths of the carrier? A. B. C. D.

Rayleigh fading Rician fading Wavelength fading Slow fading

8. Which of the reception problems below that is not due to multipath? A. B. C. D.

Delayed spreading Rayleigh fading Random Doppler shift Slow fading

9. Which causes multipath or frequency-selective fading? A. B. C. D.

Small reflector Nearer reflector Further reflector Large reflector

10. In microwave transmission using digital radio, what causes most intersymbol interference? A. B. C. D.

Delayed spreading Rayleigh fading Random Doppler shift Slow fading

11. A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor. A. B. C. D.

Fathometer Echosounder LORAN SONAR

12. The cavity resonator A. B. C. D.

Is equivalent to an LC resonant circuit In a reflect klystron has its output taken from the reflector plate Produces a frequency which is independent of the cavity size. Has a low Q factor for narrow operation.

13. At what position is the input signal inserted into a traveling-wave tube? A. B. C. D.

At the cathode end of the helix At the collector At the collector end of the helix At the control grid of the electron gun

14. Coupling into and out of a traveling-wave tube can be accompanied by a A. B. C. D.

Waveguide match Cavity match Direct coax-helix match All of the above

15. a high-power microwave pulse of the order of megawatts can be generated by a

A. B. C. D.

traveling-wave tube magnetron reflex klystron Gunn diode

16. A traveling-wave tube (TWT) amplifies by virtue of A. B. C. D.

The absorption of energy by the signal from an electron stream The effect of an external magnetic field The energy contained the cavity resonators The energy liberated form the collector

17. What is the purpose of the electromagnetic field which surrounds a traveling-wave tube? A. B. C. D.

To accelerate the electron To velocity modulate the electron beam To keep the electrons from spreading out To slow down the signal on the helix

18. Which of the following is used as an oscillator device in the SHF band? A. B. C. D.

Thyratron tube Tunnel diode Klystron tube Both B and C

19. Microwave frequencies are normally regarded as those in the range of A. B. C. D.

1 to 500 MHz 1000 to 10,000 GHz 1 to 100 GHz 10 to 1000 GHz

20. The highest frequency which a conventional vacuum-tube oscillator can generate is not limited by the

A. B. C. D.

Electron transit time Distributed lead inductance Inter-electrode capacitance Degree of emission from the cathode

21. As the electron beam moves through a klystron’s intercavity drift space A.

Frequency modulation at the input cavity creates velocity modulation at the output cavity B. Velocity modulation at the input cavity creates density modulation at the output cavity C. Density modulation at the input cavity creates velocity modulation at the output cavity D. Phase modulation at the input cavity creates velocity modulation at the output cavity. 22. The frequency of the oscillation generated by a magnetron, is mainly determined by A. B. C. D.

The flux density of the external magnet The ratio of the dc cathode voltage to the magnetic flux density The number of the cavity resonators The dimension of each cavity resonator

23. If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the A. B. C. D.

π mode π/2 mode 2π mode π/4 mode

24. The Gunn diode oscillator A. B. C. D.

Is capable of generating continuous microwave power of the order of kilowatt Generates frequencies which are below 100 MHz Operates over a positive resistance characteristic Depends on the formation of charge domain

25. What ferrite device can be used instead of duplexer of isolate microwave transmitter and receiver when both are connected to the same antenna?

A. B. C. D.

Isolator Magnetron Simplex Circulator

26. To achieve good bearing resolution when using a pulsed-radar set, an important requirement is A. B. C. D.

A narrow, antenna-beam width in the vertical plane A narrow, antenna-beam width in the horizontal plane A low repetition rate A high duty cycle

27. When used in conjunction with a radar set, the purpose of an echo box is to provide an artificial target. A. B. C. D.

Which may be used to tune the radar synchronizer Which may be used to tune the radar receiver To the tone of the pulse repetition Tune the magnetron to the correct frequency

28. In a radar-set receiver, the usual mixer stage is A. B. C. D.

And FET A tunnel diode A silicon crystal A Rochelle salts crystal

29. Klystron oscillators are most often used in the frequency range of A. B. C. D.

300 to 3000 MHz 3000 to 30000 MHz 30 to 30000 MHz 10 to 10000 MHz

30. Oscillators of a klystron tube are maintained

A. B. C. D.

By bunches of electrons passing the cavity grids By plate-to-cathode feedback By feedback between the accelerating grid and the repeller By circulating bunches of electrons within the cavities.

31. What allow microwave to pass in only one direction? A. B. C. D.

RF emitter Capacitor Varactor-triac Ferrite emitter

32. In an SHF pulsed radar set, a reflex klystron can be used as a A. B. C. D.

Single mixer stage Local oscillator Transmitter oscillator Duplexer stage

33. A Class-S Emergency Position-Indicating Radio Beacon (E.P.I.R.B) A. B. C. D.

Must be capable of floating or being secured to a survival Must have its battery replaced after emergency use May be tested during the first five minutes of any hour All of these

34. A PPI cathode-ray tube as used on a radar set A. B. C. D.

Is used to check the percentage of modulation Indicates both the range and azimuth of a target Indicates only the range of a target Is used for receiver alignment

35. The resonant frequency of a cavity resonator depends upon A. B. C.

The mode of operation Its electrical dimensions Its physical dimensions

D.

The capacitor which tunes it

36. The maximum usable range of the usual radar set (on any particular range setting) is determined by A. B. C. D.

The width of the transmitted pulses The interval between transmitted pulses The bandwidth of the receiver IF stages The duty cycle

37. A reflex klystron is oscillating at the frequency of its resonant cavity. If the reflector voltage is made slightly less negative, the A. B. C. D.

Oscillation will cease Output power would increase The frequency will decrease Bunching would occur earlier in time

38. The coarse frequency adjustment of a reflex klystron is accomplished by A. B. C. D.

The AFC system Adjusting the flexible wall of the resonant cavity An adjustment in the synchronizer Varying the repeller voltage

39. In a pulsed radar set, the STC circuit is used to A. B. C. D.

Improve the target bearing resolution Increases receiver sensitivity for echoes from targets Vary the pulse frequency in order to control the maximum target Reduce interference from the effects of sea return

40. In a pulsed radar set, the function of the duplexer is to A. B. C. D.

Aid in calibrating the display unit Prevent frequency drift in the klystron Allow the transmitter and the receiver to operate from a common antenna All of these

41. A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilowatts. Its average power is A. B. C. D.

10,000 watts 100 watts 1,000 watts 1,000,000 watts

42. The aquadag coating on the inside of PPI tube is used A. B. C. D.

To focus the beam of primary electrons To shield the electron beam from unidirectional magnetic As a second anode and to prevent the build-up of secondary field All of these

43. If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers A. B. C. D.

Must remain as before Must be increased May be decreased Must be doubled

44. The main frequency determining element of a klystron is A. B. C. D.

The repeller voltage The accelerating voltage Its resonant cavity Its mode of operation

45. A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish of a radar set. The particular effect on the performance of the radar will be A. B. C. D.

A decrease in range A reduction in horizontal resolution No noticeable effect A decrease in gain

46. Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction? A. B. C. D.

Isolator Wave trap Tunnel diode Circulator

47. It is possible to increase the maximum range of a radar equipment by A. B. C. D.

Lowering the pulse frequency Raising the peak power of the transmitter Narrowing the beam width and increasing the pulse duration All of these

48. When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have A. B. C. D.

A long time constant Low-pass filters The shortest possible time The restricted high-frequency response

49. Which of the following is used as a high power microwave oscillator? A. B. C. D.

Thyratron Magnetron Klystron Reflex-klystron

50. Which of the following operating frequencies is used for the modern loran navigational system? A. B. C.

Loran C: 100 kHz Loran D: 10.2 kHz Loran A: 1950 kHz

D.

Loran B: 900 kHz

51. Which ferrite device can be used instead of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna? A. B. C. D.

Isolator Magnetron Simplex Circulator

52. The pulse frequency is equal to A. B. C. D.

Duty cycle/pulse width The reciprocal of the pulse repetition rate Pulse width x peak power/average power All of these

53. In a radar set, a blocking oscillator can be used to A. B. C. D.

Act as the local oscillator converter stage Provide the sweep voltage for the PPI tube Produce a trigger pulse for the transmitter As a single local oscillator converter stage

54. The intensity of the echoes (target definition) on a PPI display is determined by the A. B. C. D.

Radio frequency Pulse frequency and antenna rotation rate Duty cycle Average power

55. A duplexer circuit allows a transmitter and a receiver to operate from the same antenna with virtually no interaction. This circuit may be replaced by a (an) A. B. C. D.

loss waveguide circulator isolator gyrator

56. Which of the following frequencies are used by a class-C Emergency Position-Indicating Radio Beacon (E.P.I.R.B)? A. B. C. D.

156.65 MHz 121.5 MHz 156.76 MHz and 156.8 MHz All of these

57. The repetition rate of a pulsed radar system indicates the A. B. C. D.

Frequency of the range-marker oscillator Reciprocal of the duty cycle Number of target echoes received on one second Frequencies of the duty cycle

58. The radar set, sensitivity-time control circuit A. B. C. D.

Controls the width of the magnetron pulse Is used to increase sea return Can reduce sea-return response Discriminates between targets that are very close together.

59. Which of the following is the ferrite device that buffers a microwave source from the effects of a varying load, and thereby prevents the formation of standing waves? A. B. C. D.

Circulator Duplexer Isolator Diplexer

60. Pulsed radar sets are primarily used to find the A. B. C. D.

Target’s range and bearing Size and speed of a target Speed and course of a target Target’s range of speed

61. Which of the following factors is mainly concerned in the design of an antenna system for pulsed radar set? A. B. C. D.

Duty cycle Radio frequency Pulse frequency Pulse length

62. In a radar set receivers, an ac AFC system may be used to A. B. C. D.

Automatically maintain the correct magnetron frequency Keep the IF stages on frequency Maintain the desired klystron frequency Provide automatic control of receiver gain

63. The input signal is introduced into the traveling-wave tube at the A. B. C. D.

Cathode Anode Cathode end of the helix Collector end of the helix

64. The display on the PPI scope of a radar set will have greater intensity under the following conditions A. B. C. D.

Higher antenna rotation speeds Lower pulse repetition rate Lower antenna rotation speeds Both lower antenna rotation speeds and higher pulse repetition

65. The operating frequency of loran C lies within the A. B. C. D.

LF band VLF band MF band HF band

66. The PPI tubes have an aquadag coating on the inside of the tube. The purpose of this coating is A. B. C. D.

To act as the second anode To shield the tube magnetically To decelerate the electron beam To deflect the electron beam

67. A traveling-wave tube Is used at frequencies in the order of A. B. C. D.

30 MHz 300 MHz 8000 MHz 100 MHz

68. The main benefit of using microwaves is A. B. C. D.

Lower-cost equipment Simpler equipment Greater transmission distances More spectrum space for signals

69. Radio communication are regulated in the Philippines by the A. B. C. D.

DOTC KBP NTC Department of Defense

70. Which of the following is not a disadvantage of microwaves? A. B. C. D.

Higher-cost equipment Line-of-sight transmission Conventional components are not usable Circuits are more difficult to analyze

71. Which of the following is a microwave frequency?

A. B. C. D.

1.7 MHz 750 MHz 0.98 GHz 22 GHz

72. Which of the following is not a common microwave application? A. B. C. D.

Radar Mobile radio Telephone Satellite communications

73. Coaxial cable is not widely used for long microwave transmission lines because of its A. B. C. D.

High loss High cost Large size Excessive radiation

74. Stripline and microstrip transmission lines are usually made with A. B. C. D.

Coax Parallel wires Twisted pair PCBs

75. The most common cross section of a waveguide is a A. B. C. D.

Square Circle Triangle Rectangle

76. A rectangular waveguide has a width of 1 inch and a height of 0.6 in. Its cutoff frequency is A. B.

2.54 GHz 3.0 GHz

C. D.

5.9 GHz 11.8 GHz

77. A waveguide has a cutoff frequency of 17 GHz. Which of the following signals will not be passed by the waveguide? A. 15 GHz B. 18 GHz C. 22 GHz D. 255 GHz 78. Signal propagation in a waveguide is by A. B. C. D.

Electrons Holes Electric and magnetic fields Air pressure

79. When the electric field in a waveguide is perpendicular to the direction of wave propagation, the mode is said to be A. B. C. D.

Vertical polarization Horizontal polarization Transverse electric Transverse magnetic

80. The dominant mode in most rectangular waveguide is A. B. C. D.

TE 1.0 TE 1.2 TM 0.1 TM 1.1

81. A magnetic field is introduced into waveguide by a A. B. C. D.

Probe Dipole Stripline Capacitor

82. A half-wavelength, close section of a waveguide that acts as a parallel resonant circuit is known as a(n) A. B. C. D.

Half-wave section Cavity resonator LCR circuit Directional coupler

83. Decreasing the volume of a cavity causes its resonant frequency to A. B. C. D.

Increase Decrease Remain the same Drop to zero

84. __________ is a popular microwave mixer diode. A. B. C. D.

Gunn Varactor Hot carrier IMPATT

85. Varactor and step-recovery diodes are widely used in what type of circuit? A. B. C. D.

Amplifier Oscillator Frequency multiplier Mixer

86. Which diode is a popular microwave oscillator? A. B. C. D.

IMPATT Gunn Varactor Schottky

87. Which type of diodes does not ordinarily operate with reverse bias?

A. B. C. D.

Varactor IMPATT Snap-off Tunnel

88. Low-power Gunn diodes are replacing A. B. C. D.

Reflex klystrons TWTs Magnetrons Varactor diodes

89. Which of the following is not a microwave tube? A. B. C. D.

Traveling-wave tube Cathode-ray tube Klystron Magnetron

90. In a klystron amplifier, velocity modulation of the electron beam is produced by the A. B. C. D.

Collector Catcher cavity Cathode Buncher cavity

91. A reflex klystron is used as a(n) A. B. C. D.

Amplifier Oscillator Mixer Frequency multiplier

92. For proper operation, a magnetron must be accompanied by a A. B. C.

Cavity resonator Strong electric field Permanent magnet

D.

High dc voltage

93. The operating frequency of klystrons and magnetrons is set by the A. B. C. D.

Cavity resonators DC supply voltage Input signal frequency Number of cavities

94. A magnetron is used only as a/an A. B. C. D.

Amplifier Oscillator Mixer Frequency multiplier

95. A common application for magnetron is in A. B. C. D.

Radar Satellites Two-way radio TV sets

96. In a TWT, the electron beam is density-modulated by a A. B. C. D.

Permanent magnet Modulation transformer Helix Cavity resonator

97. The main advantage of a TWT over a klystron for microwave amplification is A. B. C. D.

Lower cost Smaller size Higher power Wider bandwidth

98. High-power TWTs are replacing what in microwave amplifiers? A. B. C. D.

MESFETs Magnetrons Klystrons IMPATT diodes

99. The most widely used microwave antenna A. B. C. D.

Half-wave dipole Parabolic Hyperbolic Horn

100. ______________ is a measure of reliability expressed as the average number of hours between successive failures. A. B. C. D.

MTBF MTTR Downtime Outage time

101. The free space attenuation between two microwave antennas 40 km apart operating at 8 GHz is A. B. C. D. 102. A. B. C. D.

146.7 dB 142.55 dB 82.5 dB 86.7 dB An active microwave radio repeater that can provide drops and inserts. Broadband repeater Baseband repeater IF repeater RF repeater

103. If the correction factor k equals 4/3 of the earth’s curvature, the microwave beam would have a curvature that is ___________ than that of the earth. A. B. C. D.

More Less Equal Not related

104. The optimum clearance from an obstacle in an microwave system is accepted as __________ of the first fresnel zone radius. A. B. C. D.

0.6 0.5 0.9 1.5

105. The microwave beam curves the same than that of the earth when the value of the correction factor k equals A. B. C. D.

0 4/3 2/3 Infinity

106. The time from the transmission of a radar pulse to its reception is 0.12 ms. The distance to the target is how many nautical miles? A. B. C. D. 107. A. B. C. D.

4.85 nmi 9.7 nmi 11.2 nmi 18.4 nmi The ability of a radar to determine the bearing to a target depends upon the Antenna directivity Speed of light Speed of the target Frequency of the signal

108. The pulse duration of a radar signal is 699ns. The PRF is 185 pulses per second. The duty cycle is A. B. C. D. 109. A. B. C. D.

0.216 % 0.130 % 0.013 % 0.407 % The Doppler effect allows which characteristics of a target to be measured? Distance Azimuth Altitude Speed

110. The Doppler effect is a change in what signal characteristics produced by relative motion between the radar set and a target? A. B. C. D. 111. A. B. C. D. 112. A. B. C. D.

Amplitude Phase Frequency Duty cycle The most widely used radar transmitter component is a Klystron Magnetron TWT Power transistor Low-power radar transmitters and receivers use which component? GaAs FET Magnetron Gunn diode Klystron

113. What component in a duplexer protects the receiver from the higher transmitter output? A. B. C. D. 114. A. B. C. D. 115. A. B. C. D.

Waveguide Bandpass filter Notch filter Spark gap Most radar antennas use a Dipole Broadside array Horn and parabolic reflector Collinear array The most common radar display is the A scan Color CRT LCD PPI

116. A radar antenna using multiple diploes or slot antennas in a matrix with variable phase shifters is called a/an A. B. C. D. 117. A. B. C. D. 118.

A scan Phased array Broadside Circulator polarized array Which of the following is a typical radar operating frequency? 60 MHz 450 MHz 900 MHz 10 GHz A microwave system requires the use of repeaters when

A. B. C. D.

The intervening terrain is favorable The distances involve are grater The required reliability is meet The radio fading is unacceptable

119. Are transmission lines which convey electromagnetic waves in highest frequencies A. B. C. D. 120. A. B. C. D. 121. A. B. C. D. 122. A. B. C. D.

Twister pair of telephone wires Waveguides Power lines Coaxial cables A microwave band of 10.9 to 36. GHz is considered as C-band X-band Q-band K-band A microwave communications system space loss calculation formula. 94.2 + 20 log f + 20 log d 92.4 + 20 log f + 20 log d 94.2 + 10 log f + 20 log d 92.3 + 10 log f + 20 log d A waveguide is also a Low pass filter High pass filter Band pass filter Band stop filter

123. A method of diversity reception where the signal is transmitted on two difference frequencies over the same path

A. B. C. D. 124. A. B. C. D. 125. A. B. C. D.

Space diversity Frequency diversity Polarization diversity Wavelength diversity A wire used to reduce the skin effect AWG # 14 AWG # 15 Copper wire Litz wire Space diversity transmission means transmitting and receiving on two or more. Different frequencies Antennas operating on two different frequencies Antennas operating on the same frequencies Identical frequencies

126. The best system configuration to overcome multipath fading of microwave system over the water A. B. C. D.

Space diversity Frequency diversity Polarization diversity Wavelength diversity

127. When the value of k increases, the effective result is _______ of the equivalent curvature A. B. C. D. 128. A.

Flattening Bulging Sharp curvature All of these A traveling wave tube consists of Electron gun, helix and repeller

B. C. D.

Electron gun, helix and collector Electron gun, repeller and collector Buncher cavity and catcher cavity

129. A. B. C. D.

Advantage of periscope antenna in microwave Reduce tower height Minimize interference to and from other neighboring stations Shorten waveguide length Easy to install

130. A. B. C. D.

What is the cut-off frequency of a waveguide? The highest frequency the waveguide operates The lowest frequency the waveguide operates The same as the operating frequency The only frequency the waveguide operates.

131. When the clearance above the obstruction is equal to the radii of even fresnel zones at the point of reflection. The RSL is A. B. C. D.

Increased Decreased Constant Above threshold

132. A. B. C. D.

What is the wavelength of a wave in a waveguide? Greater than in free space Depends only on the waveguide dimensions and the free-space wavelength Inversely proportional to the phase velocity Inversely proportional to the group velocity

133. The CCIR hypothetical reference circuit covering a distance of 25000 km consists of a total of how many hops? A. B.

5 10

C. D. 134. A. B. C. D. 135. A. B. C. D. 136. A. B. C. D.

24 54 Water causes more attenuation particularly on what frequency? 20 GHz 63 GHz 183 GHz 202 GHz At what frequency does oxygen cause excessive attenuation? 60 GHz 50 GHz 40 GHz 30 GHz Which of the following is an atmospheric attenuation? Attenuation due to water vapor and oxygen Attenuation due to mist and fog Attenuation due to other gases Attenuation due to rain.

137. A microwave system operating at the 6 GHz band is carrying 600 voice channels. What is the noise loading power in dBmO? A. B. C. D.

12.78 26.78 27.78 10.25

138. _________ is a microwave link between the down-town terminal and another out of town terminal. A. B. C.

STL Uplink Downlink

D. 139. A. B. C. D. 140. A. B. C. D. 141. A. B. C. D. 142. A. B. C. D. 143. A. B. C. D.

Terrestrial Attenuator is used in the traveling wave tube to Prevent oscillation Increase gain Prevent saturation All of these Is a method of diversity reception applied to reflective path to reduce fading. Frequency diversity Space diversity Polarization diversity Wavelength diversity What is the effective earth’s radius used in communications design? 4000 miles K x 4000 miles 5000 miles K x 5280 miles IF bandwidth of a radar system is inversely proportional to Pulse width Pulse interval Peak transmit power All of these EADI stands for Electronic Air Data Indicator Electronic Altitude and Distance Indicator Electronic Altitude and Director Indicator Electronic Air and Distance Indicator

144. Which aircraft navigational system determines the time to station (TTS) or time to go (TTG)? A. B. C. D. 145. A. B. C. D.

ADF DME Timer ATC What frequency does a radio altimeter operate? 33500 kHz 43000 kHz 33500 MHz 43500 MHz

146. What inflight system allows passengers to make telephone calls, send faxes, and computer data shop and play computer games, etc.? A. B. C. D. 147. A. B. C. D. 148. A. B. C. D.

Inflight Satellite System Terrestrial Flight Telephone System World Airline Entertainment System Satellite Phone ADF stands for Audio Direction Findings Automatic Direction Finder Alternate Direction Finder Automatic Distance Finder RF carrier of the middle marker is modulated at ____ Hz. 1300 1400 1500 1600

149. Which of the following is considered as the major advantage of using a helix traveling wave tube? A. B. C. D. 150. A. B. C. D.

Cheaper Less noise High power Wide bandwidth RADAR stands for Radio Distance and Ranging Radio Detection and Ranging Radio Direction and Ranging Radio Distance and Range

Acoustics 1. An instrument designed to measure a frequency-weighted value of the sound pressure level. a. Sound-level meter b. Transducer c. Sound pressure meter d. Sound analyzer 2. A unit of noisiness related to the perceived noise level a. Noy b. Sone c. dB d. phone 3. An agreed set of empirical curves relating octave-band osund pressure level to the center frequency of the octave bands a. C-message weighting curves b. Psophometric weighting curves c. Noise rating curves d. F1A weighting curves 4. The frequency of free vibration a. Resonant frequency b. Natural frequency c. Center frequency d. Normal frequency 5. The transmission of sound from one room to an adjacent room, via common walls, floors or ceilings. a. Flanking transmission b. Refraction c. Reflection d. Reverberation 6. A measure of threshold hearing, expressed in decibels relative to a specifoed standard of normal hearing. a. Hearing loss b. Sensation level c. Hearing level d. Sound pressure level 7. A certain machine with a slightly out-of-balance motor rotating at 1800/min is fixed on a perfectly elastic mount with a static compression of 2.50 mm. Calculate the resonant frequency of mount. a. 10 Hz b. 20 Hz

c. 30 Hz d. 40 Hz

8. Calculate the lowest resonant frequency for a brick partition 120 mm thick, 4m by 2min area with longitudinal wave velocity of 2350 m/s. (Assume that it is supported at its edges.) a. 10 Hz b. 20 Hz c. 30 Hz d. 40 Hz 9. Velocity of sound in air. a. 300 m/s b. 330 m/s c. 1130 m/s d. 344 m/s 10. What is the expected critical frequency for a 120 mm thick brick wall? Assume a longitudinal wave velocity in brick of 2350 m/s and that the velocity of sound in air is 330 m/s. a. 114.5 Hz b. 214.5 Hz c. 314.5 Hz d. 414.5 Hz 11. The sound power level of a certain jet plane flying at a height of 1km is 160 dB (re1012 W). Find the maximum sound pressure level on the ground directly below the flight path assuming that the aircraft radiates sound equally in all directions. a. 59.1 dB b. 69.1 dB c. 79.1 dB d. 89.1 dB 12. Speaker is a device that a. Converts sound waves into current and voltage b. Converts current variations into sound waves c. Converts elctrical energy to mechanical energy d. Converts elctrical energy to electromagnetic energy 13. Which type of microphone operates on the principle that the electrical resistance of carbon granules varies as the pressure on the granules vary? a. Dynamic b. Crystal c. Carbon d. Ribbon-type 14. Bass response is a. Maximum highfrequency response

b. Emphasizing the high audio frequency c. Bypassing high audio frequencies d. Bypassing low audio frequencies 15. Pure tone of sound used as standard on testing a. 1 Hz b. 10 Hz c. 100 Hz d. 1000 Hz 16. ___________ is early reflection of sound. a. Echo b. Reverberation c. Pure sound d. Intelligible sound 17. Noise reduction system used for film sound in movie. a. Dolby b. dBa c. dBx d. dBk 18. What is the sound energy per unit area at right angles to the propagation direction per unit time? a. Loudness b. Coherence c. Sound pressure d. Sound intensity 19. ________ is the unit of loudness level of a sound. a. Sone b. Decibel c. Mel d. Phon 20. ____________ is the average rate of transmission of sound energy in a given direction through a cross-section area of 1 sqm at right angles to the direction. a. Sound pressure b. Loudness c. Sound intensity d. Pressure variation 21. What is the unit of pitch? a. Sone b. Phon c. Decibel d. Mel

22. A measure of the intensity of sound in comparison to another sound intensity. a. Phon b. Decibel c. Pascal d. Watts 23. Sound wave has two main characteristics which are a. Highness and loudness b. Tone and loudness c. Pitch and loudness d. Rarefraction and compression 24. Which type of microphone operated by electromagnetic induction that generates an output signal voltage? a. Carbon b. Dynamic c. Crystal d. Condenser 25. The exciter lamp in the optical sound part of a film projector draws 5 A at 10 V. How much power in watts is this light consuming? a. 10 watts b. 20 watts c. 40 watts d. 50 watts 26. Assume the speed of sound is 1,130 ft/s. What frequency has a wavelength of 1 foot, 1.5 inches? a. 500 Hz b. 1000 Hz c. 1500 Hz d. 2000 Hz 27. The wire must bring 100 average watts to a 4 ohms loudspeaker must safely carry what rms current? a. 2 A b. 4 A c. 5 A d. 6 A 28. A church has an internalvolume of 90.05 ft3 (2550 m3). When it contains customary sabine sof absorption (186 metric sabines), what will be its reverberation time in seconds. a. 2.0 b. 2.2 c. 2.5 d. 3.0

29. If the RMs sound pressure is 5lb/ft2, what is the sound presure level? a. 7.6 dB b. 108 dB c. 88 dB d. 10 dB 30. Speed that is faster than speed of sound. a. Ultrasonic b. Supersonic c. Subsonic d. Transonic 31. Sound waves travel faster in water at a ______ speed. a. 12.4 miles/sec b. 5000 ft/sec c. 186,000 ft/sec d. 3141 ft/sec 32. What is the sound power from a motor car whose SPL at a distance of 7.5 m is 87 dB assuming that it radiates sound unifomly? a. 0.15 W b. 0.21 W c. 0.24 W d. 0.18 W 33. Crest-to-crest distance along the direction to wave travel. a. Compression b. Wavelength c. Period d. Sound wave 34. Sound intensity level is _________. a. 10 log I/Iref b. 10 log P/Pref c. 20 log I/Iref d. 30 log P/Pref 35. Sound pressure level is _________. a. 20 log P/ Pref b. 30 log P/ Pref c. 10 log P/ Pref d. 20 log I/Iref 36. The most important specification of loudspeakers and microphones. a. Frequency response b. Field strength c. Power density

d. Gain 37. Lowest fequency produced by a musical instrument. a. Midrange b. Harmonic c. Reflection d. Refraction 38. Tendency of a sound energy to spread. a. Diffraction b. Rarefraction c. Reflection d. Refraction 39. Whenwaves bend away from straight lines of travel, it is called _________. a. Reflection b. Diffraction c. Rarefraction d. Refraction 40. Required time for any sound to decay to 60 dB. a. Echo time b. Delay time c. Reverberation time d. Transient time 41. The intensity needed to produce an audible sound varies with __________. a. Frequency b. Noise c. Amplitude d. Tone 42. Sound that vibrates too high for the human ear to hear (over 20 kHz). a. Subsonic b. Transonic c. Ultrasonic d. Stereo 43. Which microphone will be damaged if exposed to high temperature above 52°C? a. Dynamic b. Crystal c. Ribbon d. Capacitor 44. A thin springy sheet of bakelite or metal that permits the voice coil in a dynamic loudspeaker to move back and forth salong the core of its magnet. a. Vibrator b. Diaphragm

c. Hypex d. Spider 45. One hundred twenty µbars of pressure variation is equal to a. 120 dB SPL b. 57.78 dB SPL c. 115.56 dB SPL d. 41.58 dB SPL 46. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find the absorption effect of the materials used in metric sabines. a. 35.3 b. 10.96 c. 379.8 d. 109.6 47. What is the microphone characteristic that results in a boost in bassfrequencies for close microphone spacing? a. Field effect b. P.A. effect c. Proximity effect d. Reverberation 48. What is the audio frequency range? a. 20 kHz to 20 MHz b. 0 Hz to 20 kHz c. 300 Hz to 400 Hz d. 20 Hz to 20 kHz 49. What is the bass frequency range? a. 2500 Hz to 5000 Hz b. 5000 Hz to 10 kHz c. 40 kHz to 160 kHz d. 10 Hz to 20 kHz 50. High frequency range of audio signals. a. 2500 Hz to 5000 Hz b. 5000 Hz to 10 kHz c. 10 kHz to 20 kHz d. 20000 Hz to 30 kHz 51. What is the dB SPL of a voice paging in an office? a. 90 b. 65 c. 55-60 d. 80-85 52. What is the dB SPL of an auditorium with contemporary music?

a. 80-95 b. 85-90 c. 95-100 d. 100-105 53. What is the church dB SPL with speech reinforcement only? a. 90 b. 80-85 c. 85-90 d. 90-95 54. Intensity can also be called as a. Volume b. Loudness c. Sharpness d. Strength 55. Tje loudness of a sound depends upon the energy of motion imparted to ________ molecules of the medium transmitting the sound. a. Transmitting b. Running c. Moving d. Vibrating 56. _________ is affected by the distance between the listener and the source of the sound and its intensityvaries inversely with the square of its distance. a. Volume b. Bass c. Treble d. Loudness 57. If the distance between the listener and the source of the sound is doubled, the intensity is reduced to a. ½ b. 1/3 c. 2/3 d. 1/4 58. If the distance between the listener and the source of the sound is decreased to ½ tye original amount, the intensity of the sound would be a. 2 times as great b. 3 times as great c. 4 times as great d. 5 times as great 59. At a sensation level of 40 dB, 1000 Hz tone is a. 1000 mels

b. 500 mels c. 2000 mels d. 100 mels 60. If the sound waves are converted to electrical waves by a microphone, what is the frequency of the electric current? a. 3 - 30 MHz b. 25 – 8000 Hz c. 4 – 40 Hz d. 30 – 3000 Hz 61. For a music lover concert “A” is 440 Hz. If a musical note one octave higher were played, it would be _______ that frequency. a. One – half b. One-fourth c. Double d. Triple 62. In a 220 Hz, if a note was played one octave lower, it would be ______. a. 22 Hz b. 27.5 Hz c. 440 Hz d. 110 Hz 63. Much of music is generally reffered to in a. Harmonics b. Good hearing c. Fidelity d. Octaves 64. _________ is an undesired change in wave form as the signal passes through a device. a. Noise b. Vibration c. Distortion d. Harmonics 65. Distortion enhances intelligibly when an ________ is added. a. Equalizer b. Igniter c. Exciter d. Emulsifier 66. A class of signal processors. a. Amplifiers b. Equalizers c. Microprocessors d. Exciters

67. Half construction and internal finishes affect the final sound quality ________. a. poorly b. mildly c. significantly d. badly 68. Positioning a loudspeaker near a wall can dramatically alter its frequency response in two distinct ways namely; a. Gump and dump b. Hump and notch c. Fade and gone d. Bad and worst 69. The acoustics of most auditoria are very ________ when the room is full compared to the empty condition. a. Different b. Similar c. Good d. Bad 70. A _________ converts acoustical energy. a. Electro-acoustic b. Microphone transducer c. Microphone d. Electric Microphone 71. All microphone have two basic components namely, ___________. a. Wired and body b. Ceramic and crystal c. Diaphragm and generating element d. Coil and magnet 72. The kinds of generating elements are __________. a. Expense and fidelity b. Complexity and ruggedness c. Longevity d. All of these 73. When the average absorption is greater than 0.2, __________ formula is used to compute the actual reverberation time. a. Sabine b. Stephen and Bate c. Norris-Eyring d. Notch 74. At room temperature, what is the velocity of sound in meters/seconds? a. 348.03 cm/s

b. 980 cm/s c. 980 m/s d. 341.8 m/s 75. Calculate the velocity of sound in ft./sec. if the temperature is 1490C? a. 1530.03 ft/sec b. 1320 ft/sec c. 1357.03 ft/sec d. 1920.345 ft/sec 76. The wavelength of a sound of 20 kHz frequency is a. 16.5 m b. 16.5 cm c. 16.5 mm d. 16.5 um 77. The radio of frequencies is termed a. Octave b. Interval c. Harmonics d. Masking 78. What is the increase in sound pressure level in dB, if the pressure is doubled? a. 2 dB b. 3 dB c. 6 dB d. 4 dB 79. A term which is subjected but dependent mainly on frequency and also affected by intensity, a. Timbre b. Quality c. Frequency d. Pitch 80. An effect that occurs in the ear where a louder sound can reduce or even stop the nerve voltage generated by a weaker sound. a. Piezoelectric effect b. Skin effect c. Lasing d. Masking 81. For computation of ideal reverberation time, which formula is applicable? a. Sabine b. Stephen and Bate c. Norris-Eyring d. Notch

82. The __________ of the sound is a subjective effect which is a function of the ear and brain. a. Pitch b. Frequency c. Timbre d. Loudness 83. Define as the time taken from the intensity of sound energy in the room to drop to one millionth of its initial value. a. Reverberation time b. Transit time c. Decaying time d. Response time 84. __________ is the sound energy per unit area at right angles of the propagation direction, per unit time. a. Loudness b. Coherence c. Sound stress d. Sound intensity 85. One octave above 600 Hz is a. 601 Hz b. 800 Hz c. 1400 Hz d. 1200 Hz 86. A car horn outdoors produces a sound intensity level of 90 dB at 10 m away. At this distance, what is the sound power in watt? a. 0.63 b. 1.26 c. 0.315 d. 0.56 x 10-6 87. The unit of loudness level a. Sone b. dB c. Mel d. Phon 88. Consist of a rapid succession of noticeable echoes. a. Rarefaction b. Refraction c. Reflection d. Flutter echo 89. Laid the foundations of acoustic theory of buildings.

a. Charles H. Townes b. W.C Sabine c. A. Javin d. Stephen and Bate 90. An aural sensation by pressure variations in the air which are always produced by some source of vibrations. a. Music b. Sound c. Disturbance d. Speech 91. Considered to be the threshold of hearing. a. 10-12 W/cm2 b. 10-16 W/m2 c. 10-13 W/m2 d. 10-12 W/m2 92. The average absorption for a person is a. 5.7 units b. 4.7 units c. 6.7 units d. 3.7 units 93. The number of vibration or pressure fluctuations per seconds. a. Frequency b. Timbre c. Quality d. Pitch 94. Defined as the average rate of transmission of sound energy in a given direction through a cross-sectional area of 1 m2 at right angles to the direction. a. Sound pressure b. Loudness c. Sound intensity d. Pressure variation 95. What is the sound pressure level (SPL) of a sound having a RMS pressure of 200 N/m2? a. 150 dB b. 140 dB c. 170 dB d. 160 dB 96. The minimum sound intensity that can be heard is termed a. Threshold of feeling b. Threshold of pain c. Threshold of sensation

d. Threshold of hearing 97. What is the intensity of the sound whose RMS pressure is 200 N/m2? a. 96.9 W/m2 b. 97.9 W/m2 c. 95.9 W/m2 d. 94.9 W/m2 98. The unit of pitch. a. sone b. pitch c. dB d. Mel 99. What is the increase in sound pressure level in dB, if the intensity is doubled? a. 2 dB b. 3 dB c. 4 dB d. 6 dB 100. The velocity of sound is considered to be constant at ________ for the purpose of acoustics. a. 300 m/s b. 330 mm/s c. 330 µm/s d. 330 cm/s

Radiation and wave propagation 1. ________ is the amount of voltage induced in wave by an electro magnetic wave. a. receive voltage b. magnetic induction c. field strength d. power density 2. An electro magnetic wave consists of ___________. a. both electric and magnetic fields. b. an electric field only c. a magnetic field only d. non-magnetic field only 3. What is the lowest layer of the ionosphere? a. F1 b. F2 c. E d. D 4. Who profounded electro magnetic radiation theory? a. Sir Edward Appleton b. James Clerk Maxwell c. Christian Huygens d. Sir Isaac Newton 5. The D, E and F layers are known as ____________. a. Mark – space Layers b. Davinson- Miller Layers c. Kennely – Heaviside Layers d. Appleton Layers 6. Different grouping of the electromagnetic spectrum. a. band b. bandwidth c. channel d. group 7. What is the relation in degrees of the electric and magnetic fields in an electromagnetic wave? a. 180 degrees b. 90 degrees c. 270 degrees d. 45 degrees 8. A changing electric field gives rise to ________. a. a magnetic field b. sound field

c. electromagnetic waves d. near and far fields 9. Frequencies in the UHF range propagate by means of a. ground waves b. sky waves c. surface waves d. space waves 10. In electromagnetic waves, polarization __________. a. is caused by reflection b. is due to the transverse nature of the waves c. results from the longitudinal nature of the waves d. is always vertical in an isotropic medium 11. Electromagnetic Waves are refracted when they ___________. a. pass into a medium of different dielectric constants b. are polarized at right angles to the direction of propagation c. encounter a perfectly conducting surface d. pass through a small slot in a conducting plane 12. What is the highest layer of the atmosphere? a. ionosphere b. stratosphere c. troposphere d. ozone layer 13. What is the thickest layer of the ionosphere? a. F2 b. F1 c. D d. E 14. Effective Earth radius to true earth radius ratio. a. index of refraction b. K factor c. Fresnel zone d. path profile 15. Fading due to interference between direct and reflected rays. a. atmospheric-mutipath b. Fresnel zone c. reflection-multi path d. Rayleigh fading 16. The layer that reflects very low frequency waves and absorbs medium frequency waves. a. D Layer b. E Layer

c. F1 Layer d. F2 Layer 17. What layer is used for high-frequency day time propagation? a. D Layer b. E Layer c. F1 Layer d. F2 Layer 18. What is the highest frequency that can be sent straight upward and be returned to earth? a. MUF b. skip frequency c. critical frequency d. gyro frequency 19. High frequency range is from? a. 0.3 to 3MHz b. 3 to 30MHz c. 30 to 300MHz d. 3to 30MHz 20. Medium frequency range is from a. 0.01 to 0.03 MHz b. 0.03 to 0.3MHz c. 0.3 to 3MHz d. 3 to 30 MHz 21. In tropospheric scatter propagation, the attenuation is dependent on a. scatter angle b. take-off angle c. antenna size d. the troposphere 22. If the transmitter power remains constant, an increase in the frequency of the sky wave will a. lengthen the skip distance b. increase the range of the ground wave c. reduce the length of the skip distance d. have no effect on the ground wave range 23. What is the unit of electric field strength? a. volts per square meter b. volt per square cm c. volts per meter d. milivolt per watt 24. Velocity of a radio wave in free space. a. 186,000 miles per sec

b. 300x106 meters per sec c. 162,000 nautical mile per sec d. all of the above 25. Refers to the direction of the electric field vector in space. a. polarization b. directivity c. radiation d. ERP 26. An TEM wave whose polarization rotates. a. vertically polarized b. omnidirectional c. horizontally polarized d. circularly polarized 27. velocity of light in free space a. 300x106m/s b. 300x106km/s c. 186,000km/s d. 186,000m/s 28. What is the effective radiated power of a repeater with 200W transmitter power output, 4dB feed line loss, 4dB duplxer and circulator loss, and 10dB feed line antenna gain? a. 2000W b. 126W c. 317W d. 260W 29. Radio wave that is far from its sources is called a. Plane wave b. isotrpic wave c. vertical wave d. horizontal wave 30. Light goes from medium A to medium B at angle of incidence of 40 degrees. The angle of refraction is 30 degrees. The speed of light in B a. is the same as that in A b. is greater than that in A c. maybe any of these, depending on the specific medium d. is less than that in A 31. In a vacuum, the speed of an electromagnetic wave a. depends on its constant b. depends on its wavelength c. depends on its electric and magnetic fields d. is a universal constant

32. The depth of an object submerged in a transparent liquid a. always seems more that its actual depth b may seem less or more than its actual depth, depending on the object c. always seems less than its actual depth d. may seem less or more than its actual depth, depending on the transparent liquid 33. What is a wave front? a. a voltage pulse in a conductor b. a current in a conductor c. a fixed point in an electromagnetic wave d. a voltage pulse across a resistor 34. VHF ship station transmitters must have the capability of reducing carrier power to a. 1W b. 10W c. 25W d. 50W 35. Most of the effects an electro magnetic wave produces when it interacts with matter are due to its a. magnetic field b. speed c. frequency d. electric field 36. A mobile receiver experiences “dead” areas of reception as a result of a. atmospheric absorption b. tropospheric scatter c. sporadic E d. shading of the RF signal by hills and trees 37. When the electric field is perpendicular in the surface of the earth, what is the polarization of the TEM wave? a. elliptical b. vertical c. horizontal d. circular 38. When the magnetic field is perpendicular to the surface of the earth, what is the polarization of the TEM wave? a. circular b. horizontal c. vertical d. elliptical 39. When the magnetic field is parallel to the surface of the earth, what is the polarization of the TEM wave?

a. elliptical b. horizontal c. vertical d. circular 40. What are the two interrelated fields considered to make up an electromagnetic wave a. an electric field and a current field b. an electric field and voltage field c. an electric field and a magnetic field d. a voltage and current fields 41. How does the bandwidth of the transmitted signal affect selective fading? a. it is more pronounced at narrow bandwidths b. it is equally pronounced at both narrow and wide bandwidths c. it is more pronounced at wide bandwidths d. the receiver bandwidth determines the selective fading 42. A wide-bandwidth communications systems in which the RF carrier varies according to some predetermined sequence. a. amplitude compandored single sideband b. SITOR c. spread spectrum communication d. time-domain frequency modulation 43. A changing magnetic field gives rise to a. sound field b. magnetic field c. electric field d. nothing in particular 44. When a space-wave signal passes over a mountain ridge, a small part of the signal is diffracted down the far side of the mountain. This phenomenon is called a. discontinuity scattering b. troposheric ducting c. knife-edge diffraction d. space-wave refraction 45. The index of refraction of a material medium a. is greater than 1 b. is less than 1 c. is equal to 1 d. maybe any of the bove 46. At what speed do electromagnetic waves travel in free space? a. approximately 468 million meters per second b. approximately 186300 ft/s c. approximately 300 million m/s

d. approximately 300 million miles/s 47. What is the effective earth radius when surface refractivity, and N equals 300? a. 6370km b.7270km c.7950km d. 8500km 48. If N = 250, what is the earth radius K-factor? a. 1.23 b. 1.29 c. 1.33 d. 1.32 49. Electric field that lies in a plane perpendicular to the earths surface a. vertical polarization b. horizontal polarization c. circular polarization d. elliptical polarization 50. Electric field that lies in a plane parallel to the earth’s surface a. vertical polarization b. horizontal polarization c. circular polarization d. elliptical polarization 51. Indicate which one of the following terms applies to trposcatter propagation a. SIDs b. fading c. atmospheric storms d. faraday rotation 52. VLF waves are used for some types of services because a. of the low power required b the transmitting antennas are of convenient size c. they are very reliable d. they penetrate the ionosphere easily 53. Indicate which of the following frequencies cannot be used for reliable beyond-thehorizon terrestrial communications without repeaters a. 20KHz b. 15MHz c. 900MHz d. 12GHz 54. High-frequency waves are a. absorbed by the F2 layer b. reflected by the D leayer

c. capable of use for long-distance communications on the moon d. affected nby the solar cycle 55. Distances near the skip distance should be used for sky-wave propagation a. to avaoid tilting b. to prevent sky-wave and upper ray interference c. to avoid the faraday effect d. so as not to exceed the critical frequency 56. A ship-to-ship communications system is plague by fading. The best solution seems to be the use of a. a more directional antenna b. a broadband antenna c. frequency diversity d. space diversity 57. A range of microwave frequencies more easily passed by the atmosphere than are the others is called a a. window b. critical frequency c. gyro frequency range d. resonance in the atmosphere 58. frequencies in the UHF range normally propagate by means of a. ground waves. b. sky waves c. surface waves d. space waves 59. Tropospheric scatter is used with frequencies in the following range a. HF b. VHF c. UHF d. VLF 60. The ground wave eventually disappears as one moves away from the transmitter because of a. interference from the sky wave b. loss of line – of – sight conditions c. maximum single-hop distance limitation d. tilting 61. in electromagnetic waves, polarization means a. the physical orientation of magnetic field in space b. the physical orientation of electric field in space c. ionization d. the presence of positive and negative ions

62. an electromagnetic waves travel in free space, only one of the following can happen to them. a. absorption b. attenuation c. refraction d. reflection 63. the absorption of a radio waves by the atmosphere depends on a. their frequency b. their distance from the transmitter c. the polarization of the waves d. the polarization of the atmosphere 64. diffraction of electromagnetic waves a. is caused by reflections from the ground b. arises only with spherical wavefronts c. will occur when the waves pass through a large slot d. may occur around the edge of a sharp object

65. In an electromagnetic wave the electric field is a. Parallel to both magnetic field and the wave direction b. Perpendicular to both the magnetic field and the wave direction c. Parallel to the magnetic field and perpendicular to the wave direction d. Perpendicular to the magnetic field and parallel to the wave direction 66. The highest frequencies are found in a. X-rays b. Radio waves c. Ultraviolet rays d. Radar waves 67. Electromagnetic waves transport a. Wavelength b. Charge c. Frequency d. Energy 68. The ionosphere is a region of ionized gas in the upper atmosphere. The ionosphere is responsible for a. The blue color of the sky b. Rainbows c. Long distance radio communication d. The ability of satellites to orbit the earth 69. Light of which the following colors has the shortest wavelength

a. Red b. Yellow c. Blue d. Green 70. The quality in sound that corresponds to color in light is a. Amplitude b. Resonance c. Waveform d. Pitch 71. All real images a. Are erect b. Can appear on screen c. Are inverted d. Cannot appear on a screen 72. When a beam of light enters one medium from another, a quality that never changes is its a. Direction b. Frequency c. Speed d. Wavelength 73. Relative to the angle of incidence, the angle of refraction a. Is smaller b. Is larger c. Is the same d. Either A or B above 74. A light ray enters one medium from another along the normal. The angle of refraction is a. 0 b. 90 degrees c. Equal to the critical angle d. Dependent on the indexes of refraction of the two media 75. What layer aids MF surface-wave propagation a little and reflects some HF waves in daytime? a. E layer b. D layer c. F1 layer d. F2 layer 76. Dispersion is the term used to describe a. The splitting of white light into its component colors in regraction b. The propagation of light in straight lines c. The bending of a beam of light when it goes from one medium to another d. The bending of a beam of light when it strikes a mirror

77. The depth of an objects submerged in a transparent liquid a. Always seems less than its actual depth b. Always seems more than its actual depth c. May seems more than its actual depth, depending on the index of refraction of the liquid d. May seem less or more than its actual depth depending on the angle of view 78. Total internal reflection can occur when light passes from one medium to another a. That has a lower index of refraction b. That has a larger index of refraction c. That has the same index of refraction d. At less than the critical angle 79. When the light ray approaches a glass-air interface from the glass side at the critical angle, the angle of refraction is a. 0 b. 90 degrees c. 45 degrees d. Equal to the angle of incidence 80. The brightness of light source is called its luminous intensity , whose unit is a. Candela b. Lux c. Lumen d. Footcandle 81. Luminous efficiency is least for a a. Low-wattage light bulb b. Mercury vapour lamp c. High-wattage light bulb d. Fluorescent tube 82. The minimum illumination recommended for reading is a. 8000 cd b. 8000 lx c. 8000 lm d. 800W 83. Light enters a glass plate whose index of refraction is 1.6 at an angle of incidence of 30 degrees . the angle of refraction is a. 18 degrees b. 48 degrees c. 19 degrees d. 53 degrees 84. Light leaves a slab of transparent material whose index of refraction is 2 at an angle of refraction of 0 degrees. The angle of incidence is

a. 0 degrees b. 45 degrees c. 30 degrees d. 90 degrees 85. Light enters a glass plate at an angle of incidence of 40 degrees and is refracted at an angle refraction of 25 degrees. The index refraction of the glass is a. 0.625 b. 1.52 c. 0.66 d. 1.6 86. An underwater swimmer shines a flash light beam upward at an angle of incidence of 40 degrees. The angle of refraction is 60 degrees. The index of refraction of water is a. 0.67 b. 1.3 c. 0.74 d. 1.5 87. The critical angle of incidence for light going from crown glass (n=1.5) to ice (n=1.3) is a. 12 degrees b. 50 degrees c. 42 degrees d. 60 degrees 88. The solid angle subtended by a hemisphere about its ceter is a. π/2 sr b. 2 π sr c. π sr d. depends on the radius of the hemisphere 89. the luminous flux emitted by a 60-cd isotropic light source is concentrated on an area of 0.5m2. the illumination of the area is a. 9.6 lx b. 377 lx c. 120 lx d. 1508 lx 90. Microwave signals propagate by way of the a. Direct wave b. Sky wave c. Surface wave d. Standing wave 91. The ionosphere causes radio signals to be a. Diffused b. Absorbed

c. Refracted d. Reflected 92. Ground wave communications is most effective in what frequency range? a. 300KHz to 3MHz b. 3 to 30 MHz c. 30 to 300MHz d. Above 300MHz 93. The ionosphere has its greatest effect on signals in what frequency range? a. 300KHz to 3MHz b. 3 to 30 MHz c. 30 to 300MHz d. Above 300MHz 94. The type of radio wave responsible for long distance communications by multiple skips is the a. Groud wave b. Direct wave c. Surface wave d. Sky wave 95. Line of sight communications is not a factor in which frequency range? a. VHF b. UHF c. HF d. Microwave 96. A microwave-transmitting antenna is 550ft high. The receiving antenna is 200ft high. The minimum transmission distance is a. 20 mi b. 33.2 mi c. 38.7 mi d. 53.2 mi 97. To increase the transmission distance of UHF signal, which of the following should be done? a. Increase antenna gain b. Increase antenna height c. Increase transmitter power d. Increase receiver sensitivity 98. States that power density is inversely proportional to the distance from its source. a. Principle of reciprocity b. Inverse square law c. Huygen’s Princple d. Faraday’s law

99.

gets in contact with the ionosphere and reflected by it. a. Space wave b. Sky wave c. Surface wave d. Satellite wave 100. Highest layer in the ionosphere a. F1 b. D c. F2 d. E 101. Next lowest layer in the ionosphere. a. D b. E c. F1 d. F2 102. What is the primary cause of ionization in the atmosphere? a. Sun spot b. Cosmic rays c. Galactic disturbance d. Ultraviolet radiation 103. Which layer does not disappear at night? a. D b. E c. F1 d. F2 104. Which of the following uses surface wave propagation? a. ELF b. VLF c. MF d. All of these 105. The ability of the ionosphere to reflect a radio wave back to the earth is determined by a. Operating frequency b. Ion density c. Angle of incidence d. All of these 106. Highest frequency that can be used for skywave propagation between two given points on earth. a. Critical frequency b. MUF c. Cut –off frequency

d. UHF 107. The shortest distance measured along the earth’s surface that a skywave is returned to earth. a. MUF b. Quarter-wavelength c. Skip distance d. Skip zone 108. Fluctuation in the signal strength at the receiver. a. Interference b. Fading c. Tracking d. Variable frequency 109. Two or more antennas are used separated by several wavelengths a. Space diversity b. Frequency diversity c. Hybrid diversity d. Polarization diversity 110. Two or more receivers are used using a single antenna. a. Space diversity b. Frequency diversity c. Hybrid diversity d. Polarization diversity 111. One of the following is not a cause of fading. a. Interference between upper and lower rays of a sky wave. b. Skywaves arriving at different number of hops c. Interference due to ground reflected wave and skywave d. Diversity 112. What do you call the gigantic emissions of hydrogen from the sun? a. Solar flares b. SIDs c. Kennely-Heaviside d. Sun spots 113. Sudden ionospheric disturbance a. Solar flares b. SIDs c. Sun spots d. Intertropical convergence 114. A means beyond the line of sight propagation of UHF signals. a. Microwave propagation b. Space wave propagation

c. Troposcatter propagation d. Surface wave propagation 115. Two directional antennas are pointed so that their beams intersect in the troposphere. a. Skywave b. Surface wave c. Microwave d. Troposcatter 116. Super refraction. a. Ducting b. Trposcatter c. Skywave d. Space wave 117. A layer of warm air trapped above cooler air a. Troposphere b. SID c. Duct d. Huygen’s principle 118. Corresponds to voltage a. Electric field b. Magnetic field c. Gyro d. Direction of propagation 119. Absence of reception a. Skip distance b. Maximum usable c. Shadow zone d. Twilight zone 120. Each point in a spherical waveform maybe a source of a secondary spherical wavefront. a. Senll’s law b. Huygen’s principle c. Rayleigh’s principle d. De Morgan’s theore, 121. Ducting occurs in which region of the atmosphere? a. Stratosphere b. Troposphere c. Ionosphere d. Ozone layer 122. When is the E region most ionized? a. At midday b. At midnight

c. At duck d. At dawn 123. Transequatorial propagation is best during a. Night time b. Afternoon or early evening c. Noontime d. Morning 124. Which of the following is most affected by knife-edge refraction? a. Very high and ultra high frequencies b. High frequencies c. Medium frequency d. Low frequency 125. Which ionosphere layer has an average height of 225km at night? a. D layer b. E layer c. F1 layer d. F2 layer

Transmission Fundamentals 1. What is the opposition to the transfer of energy which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure? a. Conductance b. Resistance c. Reactance d. Impedance 2. When load impedance equals to Zo of the line, it means that the load _____ all the power. a. reflects b. absorbs c. attenuates d. radiates 3. impedance matching ratio of a coax balun. a. 1:4 b. 4:1 c. 2:1 d. 3:2 4. Which stands for dB relative level? a. dBrn b. dBa c. dBr d. dBx 5. Standard test tone used for audio measurement. a. 800 Hz b. 300 Hz c. 100 Hz d. 1000 Hz 6. When VSWR is equal to zero, this means a. that no power is applied b. that the load is purely resistive c. that the load is a pure reactance d. that the load is opened 7. _______ is the ratio of reflected voltage to the forward travelling voltage. a. SWR b. VSWR c. Reflection coefficient d. ISWR 8. Transmission line must be matched to the load to ______. a. transfer maximum voltage to the load b. transfer maximum power to the load

c. reduce the load current d. transfer maximum current to the load 9. Which indicate the relative energy loss in a capacitor? a. Quality factor b. Reactive factor c. Dissipation factor d. Power factor 10. What is the standard test tone? a. 0 dB b. 0 dBW c. 0 dBm d. 0 dBrn 11. The energy that neither radiated into space nor completely transmitted. a. Reflected waves b. Captured waves c. Incident waves d. Standing waves 12. Micron is equal to _______ meter. a. 10-10 b. 10-9 c. 10-6 d. 10-3 13. 1 Angstrom (A) is equal to _______. a. 10-3 micron b. 10-10 m c. 10-6 micron d. 10-6 m 14. Why is it impossible to use a waveguide at low radio frequencies? a. Because of the size of the waveguide b. Due to severe attenuation c. Due to too much radiation d. All of these 15. ________ is the transmission and reception of information. a. Modulation b. Communications c. Radiation d. Emission 16. What is the loss of the circuit in dB if the power ration of output to input is 0.01? a. 20 b. -20

c. 40 d. -40 17. Transmission lines are either balanced or unbalanced with respect to a. Negative terminal b. Reference c. Ground d. Positive terminal 18. The standing wave ratio is equal to _______ if the load is properly matched with the transmission line. a. Infinity b. 0 c. -1 d. 1 19. ________ is the advantage of the balanced transmission line compared to unbalanced line. a. Low attenuation b. Easy installation c. Low radiation loss d. Tensile strength 20. _______ is the method of determining the bandwidth of any processing system. a. Fourier series b. Spectral analysis c. Frequency analysis d. Bandwidth analysis 21. What causes the attenuation present in a waveguide? a. The air dielectric filling the guide b. The coating of silver inside c. Losses in the conducting walls of the guide d. Radiation loss 22. A device that converts a balanced line to an unbalanced line of a transmission line. a. Hybrid b. Stub c. Directional coupler d. Balun 23. What is the approximate line impedance of a parallel-strip line spaced 1 cm apart with the length of 50 cm? a. 10 ohms b. 15 ohms c. 18 ohms d. 23 ohms

24. What is the average power rating of RG-58 C/u? a. 25 W b. 50 W c. 75 W d. 200 W 25. A coaxial cable used for high temperatures. a. RG-58C b. RG-11A c. RG-213 d. RG-211 26. If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60dB? a. 2 b. 3 c. 4 d. 5 27. You are measuring noise in a voice channel at a -4 dB test point level, the meter reads -73 dBm, convert the reading into dBrnCO. a. 12 b. 16 c. 18 d. 21 28. The velocity factor for a transmission line a. depends on the dielectric constant of the material used b. increases the velocity along the transmission line c. is governed by the skin effect d. is higher for a solid dielectric than for air 29. Impedance inversion can be obtained by a. a short-circuited stub b. an open-circuited stub c. a quarter-wave line d. a half-wave line 30. Transmission lines when connected to antennas have a. capacitive load b. resistive load whose resistance is greater than the characteristic impedance of the line c. resistive load whose resistance is less than the characteristic impedance of the line d. resistive load at the resonant frequency 31. One of the following is not a bounded media. a. Coaxial line b. Two-wire line

c. Waveguide d. Ocean 32. The impedance measured at the input of the transmission line when its length is infinite. a. Input impedance b. Open circuit impedance c. Characteristic impedance d. Short circuit impedance 33. The following are considered primary line constants except a. conductance b. resistance c. capacitance d. complex propagation constant 34. The dielectric constants of materials commonly used in transmission lines range from about a. 1.2 to 2.8 b. 2.8 to 3.5 c. 3.5 to 5.2 d. 1.0 to 1.2 35. Typically, the velocity factor (VF) of the materials used in transmission lines range from a. 0.6 to 0.9 b. 0.1 to 0.5 c. 1.0 to 0.9 d. 0.6 to 0.8 36. For an air dielectric two-wire line, the minimum characteristic impedance value is a. 85 ohms b. 85 ohms c. 90 ohms d. 88 ohms 37. When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, its input impedance is a. inductive b. capacitive c. resistive d. equivalent to a parallel resonant LC circuit 38. A transmitter operating at 30 MHz with 4 W output is connected via 10 m of RG-8A/u cable to an antenna that has an input resistance of 300 ohms. Find the reflection coefficient. a. 0.71 b. 0.77 c. 0.97

d. 0.76 39. A quarter wave transformer is connected to a parallel wire line in order to match the line to a load of 1000 ohms. The transformer has a characteristic impedance of 316.23 ohms. The distance between centers is 4 inches. What is the percentage reduction in the diameter of the line? a. 85% b. 83% c. 86% d. 90% 40. The concept used to make one Smith chart universal is called a. ionization b. normalization c. rationalization d. termination 41. What are the basic elements of communications system? a. Source, transmission channel, transmitter b. Transmitter, receiver, transmission channel c. Information, transmission channel, receiver d. Sender and receiver 42. ________ is the transmission of printed material over telephone lines. a. Internet b. Data communication c. Telegraphy d. Facsimile 43. ________ is a continuous tone generated by the combination of two frequencies of 350 Hz and 440 Hz used in telephone sets. a. DC tone b. Ringing tone c. Dial tone d. Call waiting tone 44. ________ are unidirectional amplifiers having 20-25 decibel gain that are placed about 75 km apart used to compensate for losses along the telephone line. a. VF repeaters b. Loading coils c. Loop extenders d. Echo suppressors 45. ________ is a component in the telephone set that has the primary function of interfacing the handset to the local loop. a. Resistor b. Capacitor

c. Varistor d. Induction coil 46. Pulse dialing has ________ rate. a. 20 pulses/min b. 10 pulses/min c. 10 pulses/sec d. 80 pulses/sec 47. ________ is a telephone wire that connects two central offices. a. 2-wire circuit b. Trunk line c. Leased line d. Private line 48. The central switching office coordinating element for all cell sites that has cellular processor and a cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities. a. MTSO b. Cell site c. PTSN d. Trunk line 49. ________ in a cellular system performs radio-related functions for cellular site. a. Switching system b. Base station c. Operation and support system d. Mobile station 50. A technology used to increase the capacity of a mobile phone system. a. Frequency re-use b. Cell splitting c. TDM d. FDM 51. If the grade of service of a telephone system indicated P = 0.05, what does it mean? a. Completed calls of 5% b. Lost calls of 5% c. Lost calls of 95% d. Lost calls of 105% 52. ________ is the Out-of-Band signaling between Toll Central Offices (Bell System Standard). a. 3, 825 Hz b. 3, 700 Hz c. 2, 600 Hz d. 800 Hz

53. In a telephone system, the customer’s telephone directory numbering is from 000 to 999, what is the capacity of a telephone system numbering from 000 to 999? a. 100 lines b. 1000 lines c. 10, 000 lines d. 100, 000 lines 54. If the SWR is infinite, what type of load transmission line has? a. Purely reactive b. Purely resistive c. Purely capacitive d. Purely inductive 55. Not more than _______ digits make up an international telephone number as recommended by CCITT REC. E. 161. a. 8 b. 10 c. 11 d. 12 56. One (1) Erlang is equal to _______. a. 360 CCS b. 36 CCS c. 3.6 CCS d. 100 CCS 57. Standard tariff for flat rate telephone service beyond the normal flat rate in that area. a. WATS b. OTLP c. TIP d. DTWX 58. The standard analog telephone channel bandwidth. a. 300-3400 Hz b. 1200 Hz c. 200-3200 Hz d. 300-3000 Hz 59. Type of switching in which a pair of wire from the telephone set terminates in a jack and the switch is supervised by an operator. a. Crossbar switching b. Manual switching c. Electronic switching d. Step-by-step switching 60. Every time when the telephone is idle, the handset is in the _______ state. a. On-hook

b. Off-hook c. Busy d. Spare 61. _______ is a component in the telephone set that has the primary function of compensating for the local loop length. a. Resistor b. Varistor c. Capacitor d. Induction coil 62. What kind of receiver is used in conventional telephone handset? a. Carbon b. Electromagnetic c. Ceramic d. Capacitor 63. A voice-grade circuit using the PTN ha an ideal passband of a. 0 to 4 Hz b. 0 to 4 MHz c. 0 to 4 kHz d. 0 to 4 GHz 64. ________ is the minimum-quality circuit available using the PTN. a. Basic voice grade (VG) b. Basic voice channel (VC) c. Basic voice band (VB) d. Basic telephone channel 65. Direct distance dialing (DDD) network is called a. Private-line network b. PT network c. Dial-up network d. Trunk network 66. What is the advantage of sidetone? a. Transmission efficiency is increased b. Speaker increases his voice resulting in a strengthened signal c. No dissipation of energy in the balancing network d. Assure the customer that the telephone is working 67. ________ is a special service circuit connecting two private branch exchanges (PBX). a. Phantom line b. Tie trunk c. Tandem trunk d. Private line

68. The published rates, regulation, and descriptions governing the provision of communications service for public use. a. Toll rate b. Tariff c. Bulk billing d. Detailed billing 69. What is the power loss of a telephone hybrid? a. 1 dB b. 2 dB c. 3 dB d. 6 dB 70. Telephone channel has a band-pass characteristic occupying the frequency range of _______. a. 300-400 Hz b. 300-3400 Hz c. 300-3000 Hz d. 300-2700 Hz 71. The first Strowger step-by-step switch was used in _______. a. 1875 b. 1890 c. 1897 d. 1913 72. What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? a. 52usec b. 1.25usec c. 83.33usec d. 26usec 73. What is the CCITT recommendation for a preparation of loss plan, a variable loss plans and a fixed loss plan? a. G. 133 b. G. 141 c. G. 132 d. G. 122 74. What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? a. 0.838 mm b. 0.465 mm c. 1.626 mm d. 2.159 mm

75. What kind of cell is appropriate for load management, fast moving mobiles and lowusage areas? a. Pico cells b. Micro cells c. Nano cells d. Umbrella cells 76. In cellular networks, standard base station antennas are placed by _______. a. adaptive array b. flat plate antenna c. dipole array d. focused antenna 77. What is the basis of the first generation wireless local loop? a. Digital cellular technology b. Analogue cellular technology c. PSTN d. AMPS technology 78. When the calling party hears a “busy” tone on his telephone, the call is considered a. lost b. disconnected c. completed d. incomplete 79. Short-circuited stubs are preferred to open circuited stubs because the latter are a. more difficult to make and connect b. made of a transmission line with a different characteristic impedance c. liable to radiate d. incapable of giving a full range of reactances 80. What is the ratio of the reflected voltage to the incident voltage? a. VSWR b. ISWR c. SWR d. Coefficient of reflection 81. One method of determining antenna impedance. a. Sub matching b. Trial and error c. Smith chart d. Quarter-wave matching 82. ________ is a single conductor running from the transmitter to the antenna. a. Single-wire line b. Microstrip c. Twin-lead

d. Coaxial line 83. Coaxial cable impedance is typically _______. a. 150 to 300 ohms b. 50 to 75 ohms c. 30 to 45 ohms d. 300 to 600 ohms 84. Waveguide becomes compulsory above what frequencies? a. Above 3 GHz b. Above 10 kHz c. At 300 MHz d. Above 10 GHz 85. Nominal voice channel bandwidth is _______. a. 20 to 30 kHz b. 0 to 3 kHz c. 4 kHz d. 55 kHz above 86. Echo suppressors are used on all communications system when the round trip propagation time exceeds _______. a. 50 ms b. 30 ms c. 100 ms d. 1 ms 87. A radio transmission line of 300 ohms impedance is to be connected to an antenna having an input impedance of 150 ohms. What is the impedance of a quarter-wave matching line? a. 212 ohms b. 250 ohms c. 200 ohms d. 150 ohms 88. Quarter-wavelength line is used as _______. a. impedance transformer b. lecher line c. transmission line d. harmonic suppressor 89. The transmission lines which can convey electromagnetic waves only in higher modes is usually called a. coaxial cable b. waveguide c. power lines d. twisted wire of telephone line

90. Why is nitrogen gas sometimes used in waveguide? a. To increase the distributed capacitance b. To keep the waveguide dry c. To reduce the skin effect at the walls of the guide d. To raise the guide’s wave impedance 91. The apparent speed of propagation along a waveguide based on the distance between wavefronts along the walls of the guide is called a. group velocity b. phae velocity c. normal velocity d. abnormal velocity 92. How do you couple in and out of a waveguide? a. Wrap a coil of wire around one end of the waveguide b. Insertion of an E-probe into the waveguide c. Insertion of an H-loop into the waveguide d. Both B and C 93. A rectangular waveguide is operating in the dominant TE10 mode. The associated flux lines are established a. transversely across the narrow dimension of the waveguide b. transversely across the wide dimension of the waveguide c. in the metal walls parallel to the direction of propagation d. in the metal walls perpendicular to the direction of propagation 94. For dominant mode of a rectangular waveguide, the distance between two instantaneous consecutive positions of maximum field intensity (in a direction parallel to the walls of the waveguide) is referred to as half of the a. free-space wavelength b. cutoff wavelength in the wide dimension c. guide wavelength d. group wavelength 95. The guide wavelength, in a rectangular waveguide is a. equal to the free-space wavelength at the cutoff frequency b. equal to the free-space wavelength for the same signal frequency c. less than the free-space wavelength at the cut-off frequency d. greater than the free-space wavelength at the same signal frequency 96. Using the TE10 mode, microwave power can only be transmitted in free rectangular guide provided a. the wider dimension is less than one-half of the wavelength in free space b. the narrow dimension is less than one-quarter of the wavelength in free space c. the wide dimension is greater than one-half of the guide wavelength d. the wide dimension is greater than one-half of the wavelength in free space

97. If the signal frequency applied to a rectangular guide is increased and the dominant mode is employed a. the free space wavelength is increased b. the phase velocity increased c. the guide wavelength is increased d. the group velocity, Vg, is increased 98. If a 6 GHz signal is applied to a rectangular waveguide and the reflection angle is 20o, what is the value of the guide wavelength? a. 6.10 cm b. 5.32 cm c. 4.78 cm d. 5.00 cm 99. The inner dimensions of a rectangular wavelength are 1.75 cm by 3.5 cm. The cutoff wavelength for the dominant mode is a. 1.75 cm b. 3.5 cm c. 7.0 cm d. 0.4375 cm 100. A signal whose wavelength is 3.5 cm is being propagated along a guide whose inner dimensions are 2 cm by 4 cm. What is the value of the guide wavelength? a. 3.12 cm b. 3.89 cm c. 3.57 cm d. 6.30 cm 101. The frequency range over which a rectangular waveguide is excited in the dominant mode is limited to a. the difference between the frequency for which the reflection angle is 90o and the frequency for which angle is zero b. the difference between the frequency for which the free-space wavelength is equal to the cutoff value and the frequency for which the free-space wavelength is equal to the guide wavelength c. the difference between the frequency at which the cutoff wavelength is twice the narrow dimension d. none of these 102. If a rectangular waveguide is to be excited in the dominant mode, the E-probe should be inserted a. at the sealed end b. at a distance of one quarter –wavelength from the sealed end c. at a distance of one-half wavelength from the sealed end d. at a distance of three-quarters of a wavelength from the sealed end

103. A quarter-wave line is connected to an RF generator and is shorted out at the far end. What is the input impedance to the line generator? a. A low value of resistance b. A high value of resistance c. A capacitive resistance which is equal in the value to the line’s surge impedance d. An inductive resistance which is equal to the value to the line’s surge impedance 104. If the SWR on a transmission line has a high value, the reason could be a. an impedance mismatch between the line and the load b. that the line is non-resonant c. a reflection coefficient of zero at the load d. that the load is matched to the line 105. If a quarter-wave transmission line is shorted at one end a. there is minimum current at the shorted end b. the line behaves as a parallel-tuned circuit in relation to the generator c. the line behaves as a series-tuned circuit in relation to the generator d. there is a minimum voltage at the shorted end 106. A 50-ohm transmission line is feeding an antenna which represents a 50 ohm resistive load. To shorten the line, the length must be a. any convenient value b. an odd multiple of three quarters of a wavelength c. an odd multiple of half a wavelength d. an even multiple of a quarter of a wavelength 107. The outer conductor of the coaxial cable is usually grounded a. at the beginning and at the end of the cable b. only at the beginning of the cable and only at the end of the cable c. only at the end of the cable d. at the middle of the cable 108. A feature of an infinite transmission line is that a. its input impedance at the generator is equal to the line’s surge impedance b. its phase velocity is greater than the velocity of light c. no RF current will be drawn from the generator d. the impedance varies at different positions on the line 109. When the surge impedance of a line is matched to a load, the line will a. transfer maximum current to the load b. transfer maximum voltage to the load c. transfer maximum power to the load d. have a VSWR equal to zero 110. A lossless line is terminated by a resistive load which is not equal to the surge impedance. If the value of the reflection coefficient is 0.5, the VSWR is a. 2

b. 3 c. 4 d. 15 111. Ratio of the mismatch between the antenna and the transmitter power. a. Standing wave pattern b. Reflection coefficient c. SWR d. Index of refraction 112. Emission designation for a facsimile. a. H3E and A4E b. R3E and A4E c. F4E and J3E d. F3C and A3E 113. Commonly used telephone wire. a. AWG #19 b. AWG #18 c. AWG #30 d. AWG #33 114. What is the distance traveled by a wave in the time of one cycle? a. Frequency b. Hop c. Wavelength d. Crest 115. The velocity factor is inversely proportional with respect to the _______. a. square of the dielectric constant b. square root of the dielectric constant c. dielectric current d. square root of refractive index 116. ________ is a hollow structure that has no center conductor but allows waves to propagate down its length. a. Waveguide b. Hybrid c. Pipe d. Directional coupler 117. To connect a coaxial line to a parallel wire line, _______ is used. a. hybrid circuit b. balun c. directional coupler d. quarter-wave transformer matching circuit

118. What length for which the input power has been halved for a transmission line with an attenuation of 6 dB/km? a. 1.5 km b. 0.5 km c. 63 km d. 2 km 119. Ina waveguide, _______ is a specific configuration of electric and magnetic fields that allows a wave to propagate. a. set-up b. coupler c. channel d. mode 120. A rectangular waveguide has dimensions of 3 cm x 5 cm. What is the dominant mode cut-off frequency? a. 2 GHz b. 3 GHz c. 2.5 GHz d. 3.5 GHZ 121. ________ are transmission lines which can convey electromagnetic waves only in higher order modes? a. Coaxial cables b. Twisted pairs of telephone wire c. Power cables d. Waveguides 122. The amount of uncertainty in a system of symbols is also called a. bandwidth b. loss c. entropy d. quantum 123. The twists in twisted wire pairs a. reduced electromagnetic interference b. occur at a 30-degree angle c. eliminate loading d. were removed due to cost 124. An example of a bounded medium is a. coaxial cable b. waveguide c. fiber-optic cable d. all of the above 125. Loading means the addition of

a. resistor b. capacitor c. bullet d. inductance 126. What is the most commonly used transmission line for high frequency application? a. Two-wire balance line b. Single wire c. Three-wire line d. Coaxial 127. The characteristic impedance of a transmission line does not depend upon its a. length b. conductor diameter c. conductor spacing d. dielectric material 128. One of the following is not a common transmission line impedance. a. 50 ohms b. 75 ohms c. 120 ohms d. 300 ohms 129. For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zoand the load impedance ZL should be a. Zo = ZL b. Zo > ZL c. Zo < ZL d. Zo = 0 130. The mismatch between antenna and transmission line impedance cannot be corrected for by a. using LC matcging network b. adjusting antenna length c. using a balun d. adjusting the length of transmission line 131. ________ is a pattern of voltage and current variations along a transmission line not terminated in its characteristic impedance. a. An electric field b. Radio waves c. Standing waves d. A magnetic field 132. Which is the desirable SWR on a transmission line? a. 0

b. 1 c. 2 d. Infinity 133. A 50ohm coax is connected to a 73-ohm antenna. What is the SWR? a. 0.685 b. 1 c. 1.46 d. 2.92 134. What is the most desirable reflection coefficient? a. 0 b. 0.5 c. 1 d. Infinity 135. What is the ratio expressing the percentage of incident voltage reflected on a transmission line? a. Velocity factor b. Standing-wave ratio c. Reflection coefficient d. Line efficiency 136. The minimum voltage along a transmission line is 260 V, while the maximum is 390 V, the SWR is a. 0.67 b. 1.0 c. 1.2 d. 1.5 137. One meter is one wavelength at a frequency of a. 150 MHz b. 164 MHz c. 300 MHz d. 328 MHz 138. At very high frequencies, transmission lines act as a. Tuned circuits b. Antennas c. Insulators d. Resistors 139. A shorted quarter-wave line at the operating frequency acts like a/an a. Capacitor b. Inductor c. Series resonant circuit d. Parallel resonant circuit

140. A shorted half-wave line at the operating frequency acts like a/an a. Capacitor b. Inductor c. Series resonant circuit d. Parallel resonant circuit 141. A medium least susceptible to noise? a. Shielded pair b. Twisted pair c. Fiber-optic d. Coaxial 142. A medium most widely used in LANs? a. Parallel-wire line b. Twisted pair c. Fiber-optic cable d. Coaxial 143. The most commonly used transmission line in television system. a. Parallel-wire line b. Coaxial cable c. Waveguide d. Open-wire ceramic supports 144. The impedance of a TV transmission line depends on several factors. Which is not one of those factors? a. Diameter b. Length of the wire c. Dielectric material d. Separation between conductors 145. DC blocks are used in coaxial transmission line for the purpose of a. passing DC while blocking AC b. passing AC voltage but prevent DC c. preventing AC voltage from reaching the pre-amplifier d. preventing AC power supply voltage from being shorted by a balun or band splitter 146. _______ is a type of interference caused by off-air TV channels 2 and 4, plus a satellite dish operating on channel 3. a. Adjacent channel interference b. Ghost c. Co-channel interference d. Crosstalk 147. Dithering (in TVRO communication) is a process of a. Reducing the effect of noise on the TVRO video signal

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b. Centering the video fine tuning on TVRO channels c. Moving the feedhorn rotor to the precise angle d. Moving the actuator exactly onto the desired satellite beam A network that has an input of 75dB and an output of 35dB. The loss of the network is a. -40db b. 40db c. 40dBm d. -4dBm Important useful quantities describing waveforms. a. Time and frequency b. Voltage and current c. Frequency and voltage d. Power and frequency Halving the power means a. 6-dB gain b. 3-dB loss c. 3-dB gain d. 6-dB loss One Neper (Np) is how many decibels? a. 8.866 b. 8.686 c. 8.688 d. 8.868 A signal is amplified 100 times in power. The dB gain is a. 20dB b. 119dB c. 15dB d. 25dB Which of the following is used to measure SWR? a. Spectrum analyzer b. Reflectometer c. Oscilloscope d. Multimeter 214-056 twin lead which is commonly used for TV lead-in has a characteristic impedance of a. 52 ohms b. 75 ohms c. 600 ohms d. 300 ohms

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What is the characteristic impedance of a transmission line which is to act a s a quarterwave matching transformer between a 175 ohms transmission line and 600 ohms load? a. 300.04 ohms b. 324.04 ohms c. 310.04 ohms d. 320.04 ohms What is the EIRP in dBW of a 50dB antenna connected to a transmitter with an output of 10kW through a transmission line with loss of 5dB? a. 85dBW b. 955 dBW c. 90 dBW d. 80 dBW A coaxial cable is a good example of a/an a. Unbounded medium b. Transmission channel c. Non-metallic medium d. Bounded medium If a quarterwave transformer is required to match a 180 ohm load to a transmission line with and impedance of 300 ohms, what should be the characteristic impedance of the matching ransformer? Assume that the matching transformer is to be connected directly to the load. a. 180 ohms b. 232 ohms c. 300 ohms d. 480 ohms A transmitter of 100W RF power output, 100% modulated is operating on a frequency of 169MHz. The antenna transmission line consists of a 50 ohms coaxial cable 150ft long. The coaxial inner conductor outer diameter is 0.162in. determine the outside diameter of the outer conductor if the outer conductor has a thickness of 0.05 in(assume K=1). a. 1.0 in b. 0.9in c. 0.7in d. 0.5in In the preceding problem , calculate the line current. a. 1.7A b. 1.3A c. 1.5A d. 1.0A

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Determine also the total attenuation of the line in the preceding problem. a. 2.0dB b. 1.5 dB c. 2.5 dB d. 1.0 dB What is the maximum subscriber loop length, in ft, of a telephone system if the signalling resistance is 1800ohms using a telephone cable pair of gauge #26 with loop resistance of 83.5 ohms per 100ft. Assume the telephone set resistance is equal to 200 ohms. a. 15,161.7 feet b. 19,161 feet c. 15,300 feet d. 20,000 feet If the same subscriber loop above limits the voice attenuation to a maximum of 6dB, what is the maximum allowable subscriber loop length, in feet, using the same gauge #26 telephone wire? Assume a 2.7dB loss per mile. a. 20,000 ft b. 13,900 ft c. 15,280ft d. 11,733ft The input is 0.1W and the network gain is 13dB, the output is a. 2.0W b. 2.5W c. 1.5W d. 1.8W Known as one-tenth of a neper. a. dB b. dBm c. dBp d. dNp the input impedance of a quarterwave short-circuited transmission line at its resinant frequency is a. 0 ohms b. Infinite or an open circuit c. Ohm d. 70 ohms The ratio of the largest rms value to the smallest rms value of the voltage in the line is called a. SWR b. ISWR

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c. VSWR d. Coefficient of reflection An open-wire, two-wire transmission line is to be connected to a dipole antenna through a quarter-wave matching stub. At a frequency of 10 MHz, compute the length of the dipole a. 20 meters b. 7.5 meters c. 15 meters d. 25 meters From the preceding problem, compute also the length of the quarterwave stub. a. 15 meters b. 7.5 meters c. 20 meters d. 25 meters To find the characteristic impedance of a coaxial cable, measurements are made with (a) the far end open circuited and (b) far end short circuited, the corresponding readings being a) Ro=3ohms and Xc=55 ohms, capacitive b) RS = 10 ohms and XL = 90 ohms, inductive. What is the characteristic impedance Zo of the line? a. 75.7-j2.0 ohms b. 70.7+j1.19 ohms c. 87.5 – j5 ohms d. 70.7 – j1.97 ohms A TV antenna receives a signal measured at 200mV and is immediately amplified by a preamplifier with a 15dB gain. This amplified signal then passes through a coaxial cable with 3dB loss, what is the resulting input to the TV set, in dBmV? a. 1.98 b. 13.98 c. -1.98 d. -13.98 The characteristic impedance of a transmission line does not depend upon its___________. a. Conductor spacing b. Conductor diameter c. Length d. Conductor radius What does a power difference of -3dB mean? a. A loss of one third of the power b. A loss of one half of the power c. A loss of three watts of power d. No significant change

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Which of the following is an advantage of the balance transmission line? a. Easy installation b. Outer shield eliminates radiation losses c. Low attenuation d. None of these Waveguides are used mainly for microwave transmission because a. They are bulky at lower frequencies b. Losses are heavy at lower frequencies c. They depend on straight line propagation d. No generators are powerful enough to excite them The input is 1W and the network loss is 27dB, the output is a. 1mW b. 3mW c. 2mW d. 4mW A combiner has two inputs +30dBm and +30dBm, what is the resultant output? a. +36 dBm b. +30 dBm c. +60 dBm d. +33 dBm The ratio of the smallest to the largest rms current value is called a. SWR b. VSWR c. ISWR d. Coefficient of reflection If the ratio of the maximum current to minimum current in a transmission line is 2:1 then the ratio of the maximum voltage to minimum voltage is a. 4:1 b. 1:2 c. 1:4 d. 2:1 Two wires of 600 ohms characteristic impedance is to be constructed out of a number 12 wire (81 mils). Find the attenuation of the line at 0.6GHz per 100feet length a. 0.05 dB b. 0.55 dB c. 0.44 dB d. 0.35 dB In the preceding problem, determine the spacing between wires from center to center. a. 6 in b. 4 in

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c. 5 in d. 3 in A lossless transmission line has a shunt capacitance of 100nF/m and a series inductance of 4mH/m. What is the characteristic impedance? a. 500 ohms b. 400ohms c. 300ohms d. 200hms A ten times power change in transmission system is equivalent to a. 10dBm b. 1dB c. 20dB d. 100dB A type of transmission line employed where balanced properties are required. a. Balun b. Parallel-wire line c. Coaxial line d. Quarterwave line What is the characteristic impedance of a transmission line which has a capacitance of 40nF/ft and an inductance of 0.5mH/ft a. 111.8 ohms b. 110.8 ohms c. 112.8 ohms d. 109.8 ohms The input power to a loss-free cable is 5W. If the reflected power is 7dB down on the incident power, the output power to the load is a. 4W b. 5W c. 6W d. 7W To be properly matched the ratio of a maximum voltage along a transmission line should be equal to a. 1 b. 10 c. 50 d. 2 A coaxial line with an outer diameter of 6mm has a 50 ohms characteristic impedance. If the dielectric constant of the insulation is 1.60., calculate the inner diameter. a. 2.09cm

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b. 2.09in c. 2.09mm d. 2.09mm If an amplifier has equal input and out impedance, what voltage ratio does the gain of 50dB represent? a. 316.2 b. 325.2 c. 320.1 d. 315.0 What is the inductance per foot of a cable that has a capacitance of 50 pF/ft and a characteristic impedance of 60 ohms? a. 0.167uH/ft b. 0.178 uH/ft c. 0.19 uH/ft d. 0.18 uH/ft The ratio between the energy absorbed by a surface to the total energy received by the surface. a. Reflection coefficient b. Absorption coefficient c. Linear coefficient d. Thermal coefficient When the diameter of the conductors of a wire transmission line is held constant, the effect of decreasing the distance between the conductors is a. Increase the surge impedance b. Increase the radiation resistance c. Decrease the SWR d. Decrease the impedance The higher the gauge number if a conductor a. The bigger the diameter b. The higher the resistance or the smaller the diameter c. The higher the resistance d. None of the above A short length transmission line used to reduce/eliminate standing waves in the main transmission line. a. Stub b. Balun c. λ/4 transformer d. slot ratio of reflected power to incident power? a. Incidence

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b. Reflectance c. Reflection index d. None of these A quarter wave transformer is used to match a 600 ohms lad antenna to a ling of 52 ohms impedance, the characteristic impedance of the matching transformer is a. 200 ohms b. 150 ohms c. 176 ohms d. 300 ohms What is the capacitance of 55 miles #44 copper wire spaced 18 inches? From wire tables, #44 wire has a radius to 0.10215 in. a. 0.476uF b. 0.476nF c. 0.476pF d. 0.476fF A two-transmission line consists of No. 12 wire AWG (81mils). The distance between wire centers is 10 inches. What is the characteristic impedance of the line? a. 650 ohms b. 300 ohms c. 600 ohms d. 660 ohms In the preceding problem, what is the attenuation in dB per 100ft of the line for a frequency of 4 MHz? a. 0.05 b. 0.03 c. 0.04 d. 0.06 What is the SWR when a transmission line is terminated in a short circuit? a. Zero b. One c. Infinite d. indeterminate

1. Typical speech power A. 10 to 1000 µW B. 100 to 1000 mW C. 10 to 1000 nW D. 100 to 1000 pW 2. The maximum intelligibility for voice frequency is located between A. 250 and 500 Hz B. 1000 and 3000 Hz C. 500 and 1000 Hz D. 3000 and 5000 Hz 3. The maximum voice energy is located between A. 250 and 500 Hz B. 1000 and 3000 Hz C. 500 and 1000 Hz D. 3000 and 5000 Hz 4. A device used to measure speech volume. A. speech meter B. volume meter C. volume unit meter D. speedometer 5. By definition, for a sine wave A. 0 dBm = 0 V.U. B. 0 dBW = 0 V.U. C. 0 dBa = 0 V.U. D. 0 dBf = 0 V.U. 6. Presently, this is the “standard” frequency bandwidth for voice transmission. A. 0 to 4000 Hz B. 100 to 3400 Hz C. 300 to 3400 Hz D. 300 to 3000 Hz 7. Which of the following is commonly used wire for subscriber loop design? A. AWG # 19 B. AWG # 18 C. AWG # 30 D. AWG # 33 8. The resistance limit for No. 2 Crossbar Exchange (US) is A. 1300 Ω B. 2000 Ω C. 1250 Ω

D. 1200 Ω 9. AWG # 26 has a typical loss of A. 0.21 dB/1000 ft. B. 0.32 dB/1000 ft. C. 0.41 dB/1000 ft. D. 0.51 dB/1000 ft. 10. What is the standard voice channel spacing? A. 44 MHz B. 40 kHz C. 4 kHz D. 40 MHz 11. Which tester is used to measure SWR? A. Multimeter B. Oscilloscope C. Spectrum analyzer D. Reflectometer 12. What is singing? A. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency equal to the sum of the frequencies of the signals intermodulated. B. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency higher than that of the signal having the highest frequency. C. An undesired self-sustained oscillation in a system, generally caused by excessive positive feedback. D. An art or form of entertainment that can make one rich. 13. Which stage increases the selectivity of the circuit in an AM receiver? A. Detector B. IF stage C. Modulator D. Mixer 14. The ________ of radio receiver amplify weak signal and produce a desirable intelligence at the output speaker. A. sensitivity B. selectivity C. reliability D. fidelity 15. Full-duplex transmission means A. One-way transmission B. 24-hour transmission C. Broadcast transmission

D. Two-way simultaneous transmission 16. What is a multidrop line? A. A piece of wire with a thick insulating material that serves to protect the conductive materials from damage in the event the wire is dropped. B. A line designed to withstand high pressure. C. A line or circuit interconnecting several situations. D. A bus line 17. A passive _________ is an electronic device which reduces signal strength by a specified amount in dB. A. Splitter B. Filter C. Trimmer D. Attenuator 18. The signal quality of the calls is constantly monitored by the base station, when the quality of the calls drops below a certain specified level. The base request the MTSO to try and find a better cell site. A. Hand-off B. Cell splitting C. Roaming D. Frequency reuse 19. A digital identification associated with a cellular system. A. SAT B. SID C. ESN D. MIN 20. How many seconds does facsimile transmit a stranded page? A. 5 B. 10 C. 20 D. 25 21. A kind of recording used in facsimile. A. Electrolytic recording B. Electrothermal recording C. Electropercussive recording D. Electrostatic recording 22. A type of distortion a facsimile produce when it becomes out of synchronization? A. Pincushion B. Barrel C. Skewing D. Fattening

23. What is an acoustic coupler? A. A device that radiates audible signals via a transmitting antenna B. A device that converts electric signals into audio signals, enabling data to be transmitted over the public telephone network via a conventional telephone handset C. A device that receives audible signals and retransmits them at VHF frequencies D. A transducer 24. Cause a herringbone pattern in facsimile A. Single-frequency interference B. Crosstalk C. Phase jitter D. Noise 25. The _______ in an FM receiver causes a stronger signal to dominate over a weaker signal on the same frequency. A. Capture effect B. Flywheel effect C. Hall effect D. Skin effect 26. A device that converts a 2-wire circuit to a 4-wire circuit. A. RS-232 interface B. Hybrid circuit C. Balun D. Stub 27. ______ theory is deciding between a set of hypothesis when given a collection of imperfect measurements. A. Estimation B. Traffic C. Decision D. Nyquist 28. ______ of a data reduction says that when reducing a set of data into the form of an underlying mode, one should be maximally non-committal with respect to missing data. A. Jaynes maximum entropy principle B. Kullback principle of minimum discrimination C. Minimum discrimination\ D. Maximum entropy 29. _______ is selecting the best value of a parameter from a continuum of possible values when gives a collection if imperfect measurements A. Estimation B. Traffic C. Decision

D. Nyquist 30. Combination of madulator, channel, and detector. A. Transceiver B. Transponder C. T/R channel D. Discrete channel 31. What is the frequency band of DECT? A. 1.88 – 1.90 GHz B. 1.68 – 1.70 GHz C. 1.48 – 1.50 GHz D. 1.28 – 1.30 GHz 32. How many simultaneous calls does each DECT system can support? A. 96 B. 12 C. 24 D. 49 33. How many simultaneous calls does a DECT radio transceiver can assess at any given time? A. 120 B. 240 C. 480 D. 960 34. The AGC voltage of a radio receiver is always _______. A. Present before adjustments can be made B. DC, but may have either polarity positive DC C. Positive DC D. Negative 35. What is a concentrator? A. A system that improves the signal-to-noise ratio by compressing the volume range of a signal. B. A device that varies the characteristics of a carrier signal in accordance with the waveform of a modulating signal which contains useful information C. A switching system that lets a large number of telephone or data processing subscribers use a lesser number of transmission lines or a narrow bandwidth D. Equipment in the central office. 36. If you find that an SAW filter output is 6 dB down from the input of a receiver during test, ______ A. This is normal. B. The device if faulty C. The receiver is improperly terminated

D. The filter is not resonating 37. A triple conversion superheterodyne receiver, diode mixer stages are A. Operated in the linear region B. Operated in the nonlinear region C. Operated as Class-A amplifiers D. Operated as Class-B amplifiers 38. What is a leased line? A. A piece of wire used in a local area network in one building B. A piece of wire connecting a telephone set to a PABX C. A temporary connection of one computer to a mainframe via a modern and a telephone line D. A permanent circuit for a private use within a communication network 39. If two FM signals of different strengths are received on the same frequency A. One steady heterodyne will appear in the AM output B. Both will appear in the AF output C. Only the stronger will appear in the AF output D. Neither signal will be intelligence unless the weaker signal is at least 10 times 40. Cellular mobile system was first operated in A. 1979 B. 1981 C. 1983 D. 1985 41. TACS is a cellular system with ______ channels. A. 666 B. 1000 C. 832 D. 200 42. Supervisory Audio Tone (SAT) has _______ frequency. A. 5960 Hz B. 6000 Hz C. 6040 Hz D. 1004 z 43. What is the number of channels of a cellular system with an allocated spectrum of 25 MHz and with a channel of 30 kHz bandwidth? A. 833 B. 240 C. 1000 D. 666 44. GSSM uses what digital modulation technique? A. QAM

B. GFSK C. BPSK D. GMSK 45. What is the power output of Personal Communication System (PCS)? A. 10 mW B. 75 mW C. 150 mW D. 10 W 46. RG-B8 cable has a loss of about ______ dB at cellular frequencies up to 15 ft. length. A. 2 B. 1 C. 4 D. 3 47. The signals designed to keep the receivers and transmitters aligned. A. Carrier frequencies B. Pilot carrier signals C. Synchronizing signals D. Reference signals 48. If the spacing of a two-wire open air transmission line is 12 inches and the conductor diameter is 0.25 inch, the characteristic impedance is A. 547 Ω B. 357 Ω C. 273 Ω D. 300 Ω 49. The impedance of the quarterwave transformer used to match a 600 Ω line to a 300 Ω load is A. 382 Ω B. 424 Ω C. 565 Ω D. 712 Ω 50. When a line and a load are match the reflection coefficient is A. Unity B. Zero C. Positive infinity D. Negative infinity 51. When line is terminated in an open circuit load, the reflection coefficient is A. Unity B. Zero C. Positive infinity D. Negative infinity

52. A 300 ohms line is terminated in a resistance load of 200 ohms, the VSWR is A. 0.65 B. 1.5 C. Unity D. Zero 53. If the reflection coefficient is 0.5, the standing wave ratio is A. 0.33 B. Unity C. 3 D. Zero 54. To least the fault of the given line, a signal is fed to the line, 30 µs later the signal returned. What is the distance of the fault? A. 9000 m B. 300 m C. 100 m D. 4500 m 55. The telephone set is powered by the central office on the ring side at A. 42 to 52 Vdc B. – 42 to -52 Vdc C. 24 to 64 Vdc D. – 24 to – 64 Vdc 56. The telephone voice band frequency is from A. 300 to 4 kHz B. 400 to 3400 Hz C. 300 to 3400 Hz D. 400 to 4 kHz 57. Which of the following wire is used to transmit the signal? A. Black B. Yellow C. Red D. Green 58. The corresponding frequency for digit 7 in the touch tone telephone is A. 770 & 1477 Hz B. 852 & 1209 Hz C. 852 & 1336 Hz D. 770 & 1336 Hz 59. The physical connection between the telephone set and the switching equipment is called the A. Trunk line B. Link

C. Subscriber loop D. Leased line 60. What is the local loop of a telephone system? A. It is a two-wire or four-wire communication circuit between the customer’s premise and the central office B. It is a group of wires connecting a telephone set to a modern C. It is a four-wire circuit connecting a facsimile machine to a computer D. It is a single piece of wire connecting the subscriber’s telephone set to another set in an adjacent room. 61. Which of the ff. equipment is used in long loop design? A. Dial long lines B. Voice repeater C. Loop range extender D. All of the above 62. What is a two-wire circuit? A. A circuit usually in the subscriber loop, between the telephone set and the local central office. B. A circuit having only two terminals, both terminals having the same instantaneous voltage. C. A circuit with one input terminal, one output terminal, and a common ground. D. A circuit consisting of two transmission lines. 63. 1 mW is equal to A. 90 dBm B. 0 dBm C. -30 dBm D. 120 dBm 64. Which of the following responds to the request of a subscriber by sending a dial tone? A. Line finder B. First selector C. Connector D. Line equipment 65. The other name of Class 2 office in the North American Switching Plan. A. Primary center B. Section C. Regional center D. Toll points 66. A cell in the cellular telephone system means A. A power source B. Small area C. Large area

D. Service area 67. What is the linking point between cell phone and regular telephone? A. Base station B. Control office C. C.O. D. MTSO 68. What is the typical power output of a cellular phone? A. 5 W B. 10 W C. 1 W D. 3 W 69. When a single cell is divided into smaller cells that process is called A. Cell splitting B. Cell division C. Reuse D. Cell sharing 70. The first cell shape is a square A. Square B. Circle C. Rectangle D. Triangle 71. In order to provide 100% coverage without overlap, cellular telephone system can use A. Hexagon cell shape B. Triangle C. Rectangular D. All of the above 72. What is the beamwidth of the reflector of the receiving antenna in the base station A. 20 degrees B. 30 degrees C. 50 degrees D. 60 degrees 73. A cellular phone operates on A. Half duplex B. Full duplex C. Echoplex D. Lincomplex 74. Cellular phones transmit in the band from A. 825 to 845 MHz B. 835 to 855 MHz C. 825 to 855 MHz

D. 825 to 865 MHz 75. Cell phone receives in the band from A. 860 to 880 MHz B. 870 to 890 MHz C. 870 to 880 MHz D. 860 to 890 MHz 76. What is the frequency separation between the transmit and the receive channels? A. 30 MHz B. 45 MHz C. 55 MHz D. 40 MHz 77. For channel 1, transmit/receive frequency is A. 825.030/870.030 MHz B. 835.03/880.03 MHz C. 825.015/870.015 MHz D. 825.15/870.15 MHz 78. The number of transmit/receive channels in the cellular system is A. 625 B. 645 C. 655 D. 666 79. The transmission range of cellular telephony is generally about A. 80 km B. 65 km C. 160 km D. 16 km 80. One of the following is not an advantage of a cellular telephone system A. Privacy B. Large service area C. No interference D. Mobility 81. When the message is transferred from one cell site transmitter to another cell site transmitter as the caller crosses a boundary __________ process takes place. A. Shifting B. Hand off C. Give off D. Turn over 82. What is the sensitivity of a cellular receiver? A. 20 dB B. 40 dB

C. 50 dB D. 60 dB 83. What is the frequency deviation of the cellular telephone system? A. ±15 kHz B. ±30 kHz C. ±12 kHz D. ±75 kHz 84. Hailing channel is otherwise known as A. Conversation channel B. Calling channel C. Signaling channel D. Remote channel 85. What is an Erlang? A. It is a unit of magnetic field intensity measured around a conductor B. It is the number of erroneous bits received per unit of time C. It a unit of electrical energy radiated in space. D. It is equal to the number of simultaneous calls originated during a specific hourly period. 86. All of the cell base stations are linked together by _______ which serves as the central office and management node for the group. A. MTS B. IMTS C. MSTO D. MTSO 87. Provides interface between the mobile telephone switching office and the mobile units. A. Database B. Cell site C. Terrestrial link D. Radio transmitter 88. A phone call over the cellular network actually requires A. Simplex channels B. Half duplex channels C. Full duplex channels D. Full/full duplex 89. A method of expressing the amplitudes of complex non-periodic signals such as speech. A. Volume B. Pitch C. Frequency D. Wavelength

90. _______ is signal returned to the talker after one or more round trips between the talker and the listener. A. Singing B. Echo C. Jitter D. Crosstalk 91. ______ is a voice operated device that inserts a high loss in the opposite direction of transmission of the talking party. A. Hybrid B. 2-wire circuit C. Echo suppressor D. VNL 92. _____ is picking up of the same station at two nearby points on the receiver dial. A. Double spotting B. Hot shot C. Image frequency D. Bail shot 93. When one channel picks up the signal carried by another channel. A. Echo B. Crosstalk C. Party line D. Crosslink 94. What type of connector arrangement wherein a customer may move to another location and still retain the same telephone number. A. TPL B. Bridge C. TPS D. Party line 95. It is an advantage of sidetone. A. Transmission efficiency is increased B. Speaker increase his voice resulting in a strengthened signal C. No dissipation of energy in the balancing network D. Assures the customer that the telephone is working 96. Radio communications between points using a single share frequency. A. Simplex B. Full duplex C. Half-duplex D. Full/full duplex 97. The transmission of information from multiple sources occurring on the same facility but not as the same time.

A. FDM B. TDM C. WDM D. CDM 98. When human voice and music are transmitted, the type of communication employed is known as A. Raditechnology B. Audio frequency C. Wired audio D. Radiotelephony 99. Printed documents to be transmitted by fax are converted into baseband electric signal by the process of A. Copying B. Scanning C. Modulation D. Light variation 100. What is the most commonly used light sensor in a modern fax machine? A. Phototube B. Phototransistor C. Liquid-crystal display D. Charge couple device 101. In FM fax, the frequencies for black and white are ______ repectively. A. 1500 and 2300 Hz B. 2300 and 1500 Hz C. 1300 and 2400 Hz D. 1070 and 1270 Hz 102. Which resolution produces the best quality fax? A. 96 lines per inch B. 150 lines per inch C. 200 lines per inch D. 400 lines per inch 103. Group 2 fax uses which modulation? A. SSB B. FSK C. Vestigial sideband AM D. PSK 104. The most widely used fax standard is A. Group 1 B. Group 2 C. Group 3

D. Group 4 105. Group 3 fax uses which modulation? A. QAM B. ASK C. PSK D. GFSK 130. Block calls held condition specified the held probability at a time period equal to an average holding time. A. Erlang B B. Erlang C C. Erlang D D. Poisson 131. What is an Echo? A. A signal of the same amplitude but 180 degrees out of phase from the original signal and mixed with the original signal at the transmitter to produce a more intelligible output signal B. A wave which has been reflected or otherwise returned with the sufficient magnitude and delay for it to be perceptible in some manner as a wave distinct from that directly transmitted. C. The signal having a higher frequency than the original and transmitted back to earth by a passive satellite. D. A reflected signal. 132. What is the system used by Personal Communication Network (PCN)? A. TACS B. Modified GSM C. AMPS D. CDMA 133. Termination refers to A. Cutting both ends of a conductor B. Disconnecting a line from a transmitter C. Looking back impedance of a line with no load D. Load connected to the output end of a transmission line 134. The multiple access used by Digital European Cordless Telephone (DECT) A. CDMA B. FDMA C. TDMA D. CDMA/FDMA 135. Blocked calls delay condition specified delay probability A. Erlang B B. Erlang C

C. D. 136. A. B. C. D. 137. A. B. C. D. 138. A. B. C. D. 139. A. B. C. D. 140. A. B. C. D. 141. A. B. C. D. 142. A. B. C. D. 143. A.

Erlang D Poisson Status information provided by telephone signaling. Busy tone, dial tone and ringing Congestion and call charge data All of the above None of the above The modulation technique used by DECT. GFSK ASK QAM PSK What is a four-wire circuit? Is used between serving central offices for long-distance connections, with one pair being used for each direction of transmission. Is a circuit with three output terminals and one input terminal Is an oscillator that produces four different frequencies simultaneously A circuit consisting of four transmission lines. Cellular CDMA system uses what modulation method? GFSK ASK QAM BPSK PABX means Private All-purpose Broadcasting Exchange Private Automatic Branch Exchange Public Access Bi-directional Exchange Public Automatic Branch Exchange What is the voted cellular digital standard at TIA? Digital AMPS GSM CDMA TACS What is the number of channels for Band A and for Band B in Digital AMPS 832 416 666 888 The mobile-to-base frequency assignment for GSM system is 890-915 MHz

B. 935-960 MHz C. 870-890 MHz D. 825-845 MHz 144. The range (in miles) of a cellular CDMA system. A. 13 B. 30 C. 45 D. 20 145. In a cellular system, ________ is used to measure the spectrum efficiency. A. Radio efficiency B. Diversity C. Frequency reuse D. Radio capacity 146. Which of the following echo is completely out of control? A. Worst echo B. Reverberation C. Singing D. Feedback 147. Which of the following devices increase the battery voltage on a loop and extends its signaling range? A. Loop extender B. VF repeater C. VF amplifier D. All of these 148. Under ordinary circumstances, the CCITT recommends that the number of circuits in tandem must not exceed A. 9 B. 10 C. 11 D. 12 149. What is the system capacity of AMPS? A. 30,000 B. 60,000 C. 100,000 D. 120,000 150. NAM means A. Non Alternable Memory B. Numeric Allocation Module C. Numeric Assignment Module D. Numeric Access Module

Modulation – Chapter 3 1. ______ is the maximum sideband suppression value using filter system. A. 50 dB B. 60 dB C. 40 dB D. 30 dB 2. _______ determines the number of sideband components in FM. A. carrier frequency B. modulation frequency C. modulation index D. deviation ratio 3. One of the following transmits only one sideband. A. H3E B. R3E C. A3E D. B8E 4. What produces the sidebands on FM? A. signal amplitude B. carrier harmonics C. baseband frequency D. broadband frequency 5. Which test instrument displays the carrier and the sidebands amplitude with frequency to frequency? A. oscilloscope B. spectrum analyzer C. frequency analyzer D. amplitude analyzer 6. Mixer is also known as a ________. A. modulator B. suppressor C. converter D. beater 7. Which one of the following emission transmits the lower sideband and half of the upper sideband? A. A5C B. J3E C. A3J D. A3H 8. An FM receives signal ______. A. vary in amplitude with modulation B. vary in frequency with modulation C. vary in frequency and amplitude with wideband modulation D. is not immune to noise 9. The process of impressing intelligence on the carrier is called A. modulation B. detection

C. mixing D. impression 10. ______ is an electronic instrument used to show both the carrier and the sidebands of a modulated signal in the frequency domain. A. spectrum analyzer B. oscilloscope C. digital counter D. frequency counter 11. What part of the carrier is varied by the intelligence during modulation in an AM system? A. phase B. frequency C. amplitude D. both a and c 12. The difference between the RF carrier and the modulating signal frequencies is called the A. USB B. LSB C. Sideband D. Carrier frequency 13. What stage in a radio transmitter isolates the oscillator from the load? A. Oscillator B. Buffer C. Separator D. Mixer 14. The frequency of the unmodulated carrier in FM system is A. modulating frequency B. center frequency C. carrier frequency D. deviation frequency 15. The ratio of maximum deviation to the maximum modulating frequency is called A. carrier swing B. deviation ratio C. modulation factor D. modulation index 16. A carrier signal has A. constant amplitude B. a frequency of 20 kHz and above C. a varying amplitude D. the information content 17. The modulated peak value of a signal is 125 V and the unmodulated carrier value is 85 V. What is the modulation index? A. 0.47 B. 0.68 C. 0.32 D. 1.47 18. An 891 kHz carrier having an amplitude of 80 V is modulated by a 4.5 kHz audio signal having an amplitude of 45 V. The modulation factor is

A. 0.56 B. 0.65 C. 1.78 D. 1.25 19. What is the modulation index of an FM signal having a carrier swing of 75 kHz when the modulating signal has frequency of 3 kHz? A. 25 B. 12.5 C. 0.04 D. 0.08 20. In a FM system, if modulation index is doubled by having the modulating frequency, what will be the effect on the maximum deviation? A. No effect B. Maximum deviation doubles C. Decreases by ½ D. Increases by ¼ 21. Which of the following is considered as an indirect method of generating FM? A. Reactance modulator B. Balanced modulator C. Varactor diode modulator D. Armstrong system 22. To generate an SSB or DSB signal one must use a circuit known as A. filter modulator B. ring modulator C. balanced modulator D. reactance modulator 23. Which is the first radio receiver? A. TRF receiver B. Superheterodyne receiver C. Crystal radio receiver D. Heterodyne receiver 24. An interfering signal with a frequency equal to the received signal plus twice the IF is called A. image frequency B. center frequency C. rest frequency D. interference frequency 25. Double sideband full carrier emission type A. A3J B. H3E C. R3A D. A3E 26. Single sideband reduced carrier emission type A. H3E B. R3E C. J3E D. B8E

27. A single sideband suppressed carrier emission type. A. H3e B. R3E C. J3E D. B8E 28. Independent sideband emission type A. H3E B. R3E C. J3E D. B8E 29. Vestigial sideband emission type A. C3F B. J3E C. R3E D. B8E 30. Single sideband full carrier emission type. A. R3E B. H3E C. J3E D. B8E 31. Phase modulation emission type. A. F3E B. F3C C. F3F D. G3E 32. Which one is not an advantage of SSB over AM? A. Power saving B. Requires half the bandwidth C. Wider area of reception D. Better fidelity 33. The advantage of a high level modulated AM transmitter is A. Less audio power required B. Better fidelity C. Higher value of operating power D. Less distortion 34. The advantage of a low-level modulated AM transmitter is A. Less audio power required B. Better fidelity C. Higher value of operating power D. Less distortion 35. _____ is the bad effect caused by overmodulation in AM transmission. A. Increase in noise B. Deviation in the operating frequency C. Interface to other radio services D. Decrease in the output power 36. Which characteristic of a radio receiver refers to its ability to reject an unwanted signal?

A. Sensitivity B. Selectivity C. Fidelity D. Quality 37. What type of emission is frequency modulation? A. F3E B. G3E C. A3E D. B3E 38. AM transmission power increases with ________. A. Frequency B. Source C. Load D. Modulation 39. _______ locks the FM receiver to a stronger signal. A. Hall effect B. Capture effect C. Image frequency D. Homing 40. What is the highest percentage of modulation for AM? A. 50% B. 75% C. 100% D. 80% 41. In FM, the Carson’s Rule states that the bandwidth is equal to twice the sum of the modulating frequency and ______. A. Carrier signal B. Modulating signal C. Frequency deviation D. Image frequency 42. What is the carrier swing of an FM transmitter when modified by 75%? A. 53.2 kHz B. 48 kHz C. 56.25 kHz D. 112.5 kHz 43. The modulation system inherently more resistant to noise A. Single sideband suppressed carrier B. Frequency modulation C. Pulse-position modulation D. Amplitude shift keying 44. Subcarriers that are arranged so that the channels occupying adjacent frequency bands with some frequency space between them is known as A. Guard bands B. AM bands C. Band gap D. Void band

45. Modulation of an RF amplifier carrier results in A. Multiple channels B. Smaller antennas C. Directional propagation D. All of the above 46. A process which occurs in the transmitter A. Mixing B. Modulation C. Heterodyning D. Demodulation 47. A process which occurs in the receiver A. Beating B. Modulation C. Mixing D. Demodulation 48. One part of the transmitter that protects the crystal oscillator from “pulling”. A. Buffer amplifier B. Modulator C. Power amplifier D. Antenna coupler 49. What aspect of the carrier is changed by modulation? A. Frequency B. Phase C. Amplitude D. Depends on the type of modulation 50. The amplitude of a sine wave which is modulated by a musical program will A. Be complex B. Contain fundamental frequencies C. Contain harmonic frequencies D. All of the above 51. What will be the result of the gain level being too high for signals entering the modulator? A. Receiver noise B. Excessive volume of receiver output C. Oscillator disturbances D. Distortion and splatter 52. Amplitude modulation causes the amount of transmitter power to A. Increase B. Decrease C. Remain the same D. Double 53. When a carrier is modulated 100%, the total power increases by what percentage over that of the carrier alone? A. 25% B. 50% C. 75% D. 100%

54. When the amplitude of the modulating voltage is increased for AM, the antenna current will A. Increase B. Decrease C. Remain constant D. Decrease exponentially 55. An increase in transmitter power from 25W to 30W will cause the antenna current to increase from 700mA to A. 800 mA B. 750 mA C. 767 mA D. 840 mA 56. A second modulating tone having the same amplitude but a different frequency is added to the first at the input to the modulator. The modulation index will be increased by a factor of A. B. C. 2 D. 3 57. A 1000 kHz carrier is modulated by a 2500Hz tone. One frequency component of the modulated signal is A. 1200 Hz B. 5000 Hz C. 1002.5 kHz D. 2500 Hz 58. A 1200 kHz carrier is amplitude-modulated by two tones of 500 Hz and 700 Hz. Which one is a frequency component of the modulated wave? A. 1195 kHz B. 1199.3 kHz C. 1199.7 kHz D. 1205 kHz 59. Identify a modulation method, or methods in use for a common-emitter configuration A. Base modulation B. Emitter modulation C. Collector modulation D. Both A and C 60. The RF signal injected into a balanced modulator is 10MHz and the modulating frequency is 1 kHz. Which frequency, or frequencies, will not appear in the output? A. 9.999 MHz B. 10 MHz C. 10.0001 MHz D. Both A and B 61. Unwanted sidebands in SSB equipment can be suppressed by one or more of the following methods. A. Phasing method B. Filter method C. Decoder method D. Both A and B

62. Envelope detection is concerned with the process of A. Mixing B. Heterodyning C. Modulation D. Rectification 63. Diagonal clipping in envelope detection will result in A. Distortion B. Phase reversal C. Reduced sensitivity D. Amplitude damage 64. Product detection requires the process of A. Rectification B. Heterodyning C. Decoding D. Phase shifting 65. A sine wave which is coherent with carrier has identical A. Amplitude B. Frequency C. Phase angle D. Both B and C 66. Frequency modulation and phase modulation are collectively referred to as A. Stereo B. Angle modulation C. High fidelity modulation D. FCC modulation 67. In FM, the change in carrier frequency is proportional to what attribute of the modulating signal? A. Angle B. Frequency C. Amplitude D. Tone 68. A louder sound, when generating the modulating waveform for FM, will cause a greater A. Carrier amplitude B. Angle amplitude C. Distortion at the receiver D. Frequency deviation 69. If a positive change in modulation signal level of 200 mW will cause a positive frequency deviation of 10 kHz, what will be the frequency deviation for a negative change of 10 mV in the level of the modulating signals? A. 0 B. -5 kHz C. +5 kHz D. +0 kHz 70. A particular 15 kHz modulation tone results in a peak frequency deviation of 75 kHz. What is the modulation index? A. 5

B. 15 C. 75 D. 3 71. A 15 kHz sine wave frequency modulates an 88 MHz carrier. A sideband frequency will be found at A. 87.970 MHz B. 87.985 MHz C. 88.015 MHz D. All of these 72. A device whose capacitance is deliberately made to be a function of the applied voltage A. Varactor diode B. UJT C. SAW D. Variable capacitor 73. A reactance modulator is one method of obtaining A. Indirect FM B. Direct FM C. Demodulation D. Low frequency filtering 74. A device, now available in IC form, is useful for direct FM and as one element in the phselocked loop. A. AFC B. AGC C. VCO D. LPF 75. _____ is a frequency change process, whereby the phase deviation and frequency deviation are multiplied by some fixed constant. A. Translation B. Multiplication C. Division D. Addition 76. A circuit that has the function of demodulating the frequency-modulated signal. A. AFC B. Envelope detector C. Decoder D. Foster-Seeley discriminator 77. The ratio detector is superior to the slope detector because A. It is less sensitive to phase modulation B. It is less sensitive to noise spikes C. It is less sensitive to interference causing AM D. Both B and C 78. One implementation of a pulse averaging discriminator is A. A free-running multivibrator B. A crystal-controlled oscillator C. A quartz crystal filter D. A triggered multivibrator

79. A 10% increase in the frequency of a constant-width pulse train should cause what change in its average value? A. -10% B. -1% C. +1% D. +10% 80. Two different signals can be coherent if they A. Have the same amplitude B. Are both sine waves of different frequencies C. Originate in the same physical equipment simultaneously D. Have the same frequency 81. A quadrature detector requires that A. Four gates bee provided B. The inputs are coherent C. The inputs are incoherent D. The inputs are identical 82. In a phase-locked loop, the VCO is the abbreviation for A. Variable coherent output B. VHF communication oscillator C. Voltage-controlled oscillator D. Vien-count oscillator (neutralized) 83. Identify an advantage, or advantages of a properly designed FM system. A. Relative immunity to atmospheric noise (lightning) B. Reduced bandwidth required C. No noise of any kind D. The noise figure is inversely proportional to the modulation index 84. The output of a balanced modulator A. LSB and USB B. LSB C. USB D. Carrier 85. If the modulation index of an AM wave is changed from 0 to 1, the transmitted power is A. Unchanged B. Halved C. Doubled D. Increased by 50% 86. Which of the following is not a baseband signal of modulation? A. Audio signal B. Video signal C. RF carrier D. Binary coded pulses 87. If the unmodulated level peak carrier amplitude is doubled in an AM signal, the perfect modulation is ________. A. 20 B. 50 C. 100

D. 200 88. Balanced modulator circuit when inserted in the equivalent suppresses the ___________ A. Carrier B. Upper sideband C. Lower sideband D. Baseband signal 89. The carrier of a 100% modulated AM wave is suppressed, the percentage power saving is __. A. 100% B. 50% C. 83% D. 66.66% 90. If the modulation index if an AM wave is doubled, the antenna current is also doubled, the AM system being used is A. H3E B. J3E C. C3F D. A3E 91. 100% modulation in AM means a corresponding increase in total power by _______. A. 100% B. 50% C. 75% D. 25% 92. A single-tone amplitude modulated wave has _______. A. 2 components B. 3 components C. 4 components D. 2n + 1 components 93. A carrier signal has ________. A. Constant peak amplitude B. Frequency range of 20 – 20,000 Hz C. A varying amplitude D. The information 94. The modulating system is _________ if the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. A. Amplitude modulation B. Phase modulation C. Frequency modulation D. Pulse modulation 95. What is the modulation index of an FM signal if its modulating frequency is doubled? A. No effect B. Twice the original index C. Four times the original index D. One-half the original index 96. An AM transmitter is rated 1000 W at 100% modulation. How much power required for the carrier? A. 1000 W

B. 666.6 W C. 333.3 W D. 866.6 W 97. Standard way of designating AM A. A3E B. B3E C. AHE D. C3F 98. _____ is the circuit used to detect frequency modulated signal. A. Discriminator B. Modulator C. Modem D. Detector 99. _____ is an information signal that is sent directly without modulating any carrier. A. C-band B. Q-band C. Baseband D. Broadband 100. Both frequency and phase modulation utilize ______ modulation. A. Digital B. Phase C. Amplitude D. Angle 101. It is the width of frequencies within the spectrum occupied by a signal and used by the signal for conveying information. A. Band B. Bandwidth C. Electronic spectrum D. Frequency band 102. Which transmit only one sideband? A. H3E B. C3F C. A3E D. B8E 103. ______ is kind of modulation in which the modulated wave is always present. A. Carrier modulation B. Continuous modulation C. Log-periodic modulation D. Square-wave modulation 104. A type of modulation in which no signal is present between pulses. A. Pulse modulation B. FSK C. QAM D. PAM 105. What describes the amount of amplitude change present in an AM waveform? A. Percent modulation

B. Modulation constant C. Envelope of modulation D. Coefficient of modulation 106. _______ is a form of amplitude distortion introduced when the positive and negative alternations in the AM modulated signals are not equal. A. Envelope distortion B. Spurious emission C. Carrier shift D. Johnson noise 107. What is the advantage of phase modulation over direct FM frequency modulation? A. Multipliers can be used B. The deviation is smaller C. Simplicity and practicality D. The oscillator is crystal-controlled 108. If the spectrum is shifted in frequency with no other changes, this is known as A. Frequency multiplication B. Sideband movement C. Baseband reorientation D. Frequency translation 109. A device which is capable of causing frequency translation A. High-Q tank circuit B. Balanced modulator C. Low-Q tank circuit D. IF strip 110. If the frequency of each component in a signal spectrum is increased by the same fixed amount, this known as A. Modulation B. Frequency translation C. Up conversion D. Both B and C 111. A particular amplifier is designed to be a frequency doubler. If the input signal frequency is 15.4 MHz, a circuit in the output will be tuned to A. 7.7 MHz B. 15.4 MHz C. 30.8 MHz D. 61.6 MHz 112. A sine wave of 293 MHz is phase-modulated to achieve a maximum phase deviation of 0.2 radian. After passing through a frequency tripler, the maximum phase deviation will be A. 0.2 radian B. 0.3 radian C. 0.4 radian D. 0.6 radian 113. Any device to be used as a frequency multiplier must be A. Active B. Passive C. Linear

D. Nonlinear 114. A particular amplifier circuit used for frequency doubling. A. Push-push B. Push-pull C. Pull-push D. Pull-pull 115. Frequency division is useful in the implementation of a A. AM demodulator B. Frequency synthesizer C. AGC circuit D. FM demodulator 116. Frequency division by 12 will require how many flip-flops in the counter? A. 3 B. 4 C. 6 D. 12 117. Identify an electronic device, not specifically designed for the purpose, which can be used as a phase detector. A. Wien bridge B. Colpitts oscillator C. Balanced modulator D. Butterworth filter 118. A particular frequency synthesizer contains only a single crystal. What words describe this synthesizer? A. Crystal modulated B. Inexact C. Indirect D. Deficient 119. A recognizable feature of a CW transmitter is A. Keyed transmitter B. Power amplification C. Frequency generation D. All of these 120. The term “pulling” refers to A. The change of the crystal oscillator frequency by loading B. One half-cycle operation of a push-pull amplifier C. Loading on the transmitter caused by the antenna connection D. Reduction of the power supply terminal voltage as the transmitter is keyed. 121. When frequency modulation is achieved by initial phase modulation, this is called A. Angular modulation B. Direct FM C. Indirect FM D. Indirect synthesis 122. A disadvantage of direct FM is the need for A. AGC B. AFC

C. A frequency synthesizer D. Phase modulation 123. Direct FM can be achieved by A. A reactance tube modulator B. A varactor diode C. And AGC circuit D. Both A and B 124. A receiver in which all RF amplifier stages require manual tuning to the desired RF is called A. Superheterodyne B. Autodyne C. TRF D. AFC 125. Why is it often necessary to precede the demodulator by amplifier stages in a receiver? A. To improve fidelity B. To reduce receiver noise C. To eliminate image response D. Weak antenna signals 126. A serious disadvantage of the TRF receiver. A. Bandwidth variations over the tuning range B. The weight and cost C. The requirements for a closely regulated power supply D. The requirements for a half-wave antenna 127. Identify which is not a part of a superheterodyne receiver. A. Local oscillator B. Modulator C. IF amplifier D. Demodulator 128. Which major element will not be found in every superheterodyne receiver? A. R–F amplifier B. Mixer C. Local oscillator D. IF amplifier 129. Which major element of a superheterodyne receiver must be nonlinear? A. R-F amplifier B. Mixer C. Local oscillator D. IF amplifier 130. The change of the modulated carrier frequency from the original RF to the IF of the superheterodyne receiver is known as A. Frequency multiplication B. Frequency allocation C. Frequency substitution D. Frequency translation 131. The key to achieving receiver sensitivity is the reduction of A. Image response

B. Mixer harmonic products C. Spurious frequency response D. Internal noise 132. Which of the following receiver design objectives is not impossible? A. Elimination of galactic noise B. Elimination of atmospheric noise C. Elimination of man-made noise D. Reduction of receiver internal noise 133. In comparing the S/N ratio for the input to the receiver with the S/N ratio for the output, the latter is A. Smaller B. The same C. Greater D. Infinite 134. The characteristic of a receiver that specifies the self-generated noise. A. Noise immunity B. Noise factor C. Noise figure D. Noise margin 135. An FM receiver with an I-F of 10.7 MHz is tuned to 98.7 MHz. What is the numerical value of the image frequency? A. 77.3 MHz B. 88.0 MHz C. 109.4 MHz D. 120.1 MHz 136. A source of RF interference exists at 109.9 MHz. For which frequency in the FM broadcast band will this be the image frequency? A. 21.4 MHz B. 88.5 MHz C. 99.2 MHz D. 110.7 MHz 137. The ratio of the superheterodyne receiver response at the desired carrier frequency to that at the image frequency is called A. The sensitivity B. The selectivity C. The image frequency D. The image rejection ratio 138. The core of an IF transformer usually contains A. Teflon B. Computer nylon

C. Powdered iron D. Laminated steel 139. Shape factor is a measure of A. Bandwidth B. Skirt steepness C. Coupling coefficient D. Critical coupling 140. _______ is the function which tends to maintain the sound volume level of a voice receiver nearly constant for a large signal strength range. A. Squelch B. Muting C. AGC D. AFC 141. The function which tends to silence the receiver in the absence of transmitted carrier. A. Squelch B. Muting C. AGC D. AFC 142. What device is incorporated in a communications receiver to reduce impulse noise? A. Front-end processor B. Squelch circuit C. AGC D. Noise blanker 143. What type of signal in which a receiver selectivity of 2.4 kHz in the I-F circuitry is optimum? A. FM voice B. Double-sideband AM voice C. FSK data D. SBB voice 144. If the input to a detector stage is an amplitude-modulated (A3E) IF signal then the output from the stage is A. A lower frequency carrier B. The audio voice information C. A Morse-code signal D. The upper or lower set of sidebands 145. In a capacitive type, reactance-tube modulator connected across an oscillator tuned circuit, a more negative voltage on the grid of the reactance tube will cause A. An increase of the oscillator frequency B. An decrease of oscillator frequency C. An increase of the reactance-tube capacitance

D. An increase of the reactance tube ac plate current 146. The limiting condition for sensitivity in a communications receiver is A. The noise floor of the receiver B. Power supply output ripple C. The two-tone intermodulation distortion D. The input impedance to the detector 147. When a communications receiver is tuned to a strong signal, the AGC bias is measured and found to be zero. The fault cannot be caused by a/an A. Defective IF stage B. Defective local oscillator C. Defective RF stage D. Open circuit in the AGC’s filter capacitor 148. The term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received A. Cross-modulation interference B. Intermodulation interference C. Receiver quieting D. Capture effect 149. The limiter stage of an FM receiver A. Behaves as a low-pass filter B. Limits the amplitude of the IF signal to the required level C. Behaves as a high-pass filter D. Behaves as a bandstop filter 150. Motorboating (low-frequency oscillations) in an amplifier can be stopped by A. Grounding the screen grid B. Connecting a capacitor between the B+ and lead ground C. By passing the screen grid resistor with a 0.1 µF capacitor D. Grounding the plate 151. An effect in which, the modulation of an unwanted signal is transferred to the desired carrier. A. Crossmodulation B. Intermodulation C. Modulation mixing D. Image-channel interference 152. Leads should be kept as short as possible in radio circuit so that A. Skin effect is reduced B. There is less hysteresis effect C. There is less dielectric loss D. Stray coupling is minimized

153. The number of voice transmissions that can be packed into a given frequency band for amplitude-compandored single-sideband systems over conventional FM-phone systems. A. 2 B. 18 C. 16 D. 4 154. Neutralization of an RF amplifier stage can be necessary in order to A. Increase the amplifier’s gain B. Prevent the generation of spurious oscillations C. Reduce the amplifier’s gain D. Reduce the level of the output harmonics 155. The ability of a communications receiver to perform well in the presence of strong signals outside the band of interest is indicated by what parameter? A. Blocking dynamic range B. Noise figure C. Signal-to-noise ratio D. Audio output 156. Stages that are common to both AM and FM receivers A. Tuner, local oscillator, detector, AF amplifier B. RF amplifier, mixer, IF amplifier, AF amplifier C. Local oscillator, RF amplifier, frequency discriminator, detector D. Tuner, IF amplifier, detector, AF amp 157. Occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a receiver A. Filter ringing B. Undesired signals will reach the audio stage C. Output-offset overshoot D. Cross-modulation distortion 158. What stage mainly determines a communication receiver’s sensitivity? A. IF amplifier B. Mixer stage C. Detector stage D. RF amplifier 159. What is the main advantage of FM over AM? A. Better signal-to-noise-ratio B. Narrower bandwidth C. Greater propagation range D. Total freedom from adjacent-channel interference 160. An amplitude modulation created in an amplifier before the final RF stage. A. Low-level modulation

B. High-level modulation C. Direct modulation D. Indirect modulation 161. Receiver desensitizing can be reduced by A. Increasing the transmitter audio gain B. Decreasing the receiver squelch gain C. Increasing the receiver bandwidth D. Ensuring good RF shielding between the transmitter 162. In a narrow-band FM system, the deviation ratio is commonly one and the highest audio frequency is generally limited to A. 300 Hz B. 10,000 Hz C. 3,000 Hz D. 7,500 Hz 163. A type of emission is produced when an amplitude modulated transmitter is modulated by a facsimile signal A. A3F B. F3F C. A3C D. F3C 164. Where is the noise generated which primarily determines the signal to noise ratio in a VHF (150 MHz) marine band receiver? A. In the detector B. In the atmosphere C. In the ionosphere D. In the receiver front end 165. Cross-modulation in a receiver can be reduced by A. Installing a filter at the receiver B. Using a filter at the receiver C. Increasing the receiver’s RF gain while decreasing the AF D. Adjusting the pass-band tuning 166. What is the emission designation for FM telephony? A. F3E B. G3E C. J3E D. H3E 167. What is the cause of receiver desensitizing? A. The presence of a strong signal on a nearby frequency B. Audio gain adjusted too low C. Squelch gain adjusted too high

D. Squelch gain adjusted too low 168. In a phase-modulated signal (indirect FM), the frequency deviation is directly proportional to the A. Carrier amplitude only B. Amplitude of the modulating tone and frequency of the carrier C. Carrier frequency only D. Modulating signal amplitude only 169. An RF stage precedes the mixer stage in a superhet receiver. One advantage of including this RF stage is A. Better selectivity B. Better rejection ratio C. Greater sensitivity D. Improved signal-to-noise-ratio 170. Two factors that determine the sensitivity of a receiver. A. Dynamic range and third-order intercept B. Cost and availability C. Bandwidth and noise figure D. Intermodulation distortion and dynamic range 171. What is an undesirable effect of using too-wide a filter bandwidth in the IF section of a receiver? A. Undesired signals will reach the audio stage B. Output-offset overshoot C. Thermal-noise distortion D. Filter ringing 172. A system containing a limiter stage, a discriminator, and a de-emphasis circuit? A. Direct FM transmitter B. Indirect FM transmitter C. Single sideband AM receiver D. FM receiver 173. The limiter stage of an FM receiver A. Prevents any amplitude modulation of the IF signal B. Limits the amount of frequency deviation in the IF signal C. Limits the overall bandwidth of the IF stages D. Corrects any deviation in carrier frequency 174. High selectivity occurs when the degree of coupling between a receiver’s RF stages is A. Tight B. Loose C. Critical D. Adjusted for maximum power transfer

175. A carrier is phase modulated by a test tone. If the amplitude and the frequency of the tone are both doubled, the amount of the deviation is A. Doubled B. Unchanged C. Halved D. Multiplied by four 176. The degree of selectivity desirable in the IF circuitry of a single-sideband receiver. A. 1 kHz B. 2.4 kHz C. 4.2 kHz D. 4.8 kHz 177. The component most apt to break down in the radio circuit is the A. Crystal B. Resistor C. Transformer D. Diode 178. The base in an RF amplifier is grounded in order to A. Avoid the requirement of neutralizing the stage B. Raise the input impedance C. Lower the output impedance D. Obtain maximum power output 179. The AM detector performs two basic functions in the receiver. A. Rectifies and filters B. Amplifiers and filters C. Buffer and amplifier D. Buffer and detector 180. A varactor diode can be used in a/an A. Direct FM modulator circuit B. AFC circuit in a direct FM transmitter C. Phase-modulator circuit D. All of these 181. Receiver interference is not reduced by including a/an A. Crystal filter B. Insulating enclosures around the receiver C. Wave trap D. RF stage 182. What is the emission C3F? A. RTTY B. SSB C. Television

D. Modulated CW 183. What is the approximate dc input power to a class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output is 500 W? A. Approximately 1000 W B. Approximately 800 W C. Approximately 250 W D. Approximately 600 W 184. Which of the following stages in an FM receiver is responsible for drastically reducing the effect of static noise during the reception of a signal A. De-emphasis circuit B. Mixer stage C. Squelch circuit D. Limiter stage 185. The letters “SSSC” stands for A. Single sideband, single carrier B. Suppressed sideband, single channel C. Suppressed sideband, single carrier D. Single sideband, suppressed carrier 186. For many types of voices, what is the ratio of PEP-to-average power during a modulation peak in a single-sideband phone signal? A. Approximately 1.0 to 1 B. Approximately 25 to 1 C. Approximately 100 to 1 D. Approximately 2.5 to 1 187. In most mixers, the oscillator frequency is ______ than the carrier frequency of the input signal. A. Higher B. Lower C. The same D. 10 kHz above 188. Features of a transmitter’s buffer stage include A. High stage B. Harmonic generation C. Improvement in frequency stability of the oscillator D. Low input impedance 189. Type of emission produced when an amplitude modulated transmitter is modulated by a television signal A. F3F B. A3C C. F3C

D. A3F 190. A network is A. A network consisting entirely of four inductors or four capacitors B. A power incidence network C. An antenna matching network that is isolated from ground D. A network consisting of one inductor and two capacitors 191. How is G3E FM-phone signals produced? A. A network consisting modulator on the audio amplifier B. With a reactance modulator on the final amplifier C. With a reactance modulator on the oscillator D. With a balanced modulator on the oscillator 192. A way of eliminating auto interference to radio reception A. Installing resistive spark plugs B. Installing capacitive spark plugs C. Installing resistors in series with the spark plugs D. Installing two copper-braid ground strips 193. The carrier in an AM transmitter is the A. Transmitter’s output signal when the modulation is present B. Transmitter’s output signal when the modulation is zero C. Output signal from the crystal oscillator D. RMS value of the AM signal 194. What stage feeds the discriminator of an FM receiver? A. Local oscillator B. Mixer stage C. Final IF amplifier, which also acts as a limiter stage D. Buffer 195. In an FM receiver, the stage that has the IF signal is input and the audio signal output. A. Limiter B. Audio amplifier C. IF amplifier D. Discriminator 196. What is capture effect? A. All signals on a frequency are demodulated by an FM receiver B. The loudest signal received is the only demodulated signal C. All signals on a frequency are demodulated by an AM receiver D. The weakest signal received is the only demodulated signal 197. A double-sideband phone signal can be generated by A. Feeding a phase-modulated signal into a low-pass filter B. Modulating the plate voltage of a class-C amplifier C. Using a balanced modulator followed by a filter

D. Detuning a Hartley oscillator 198. Pre-emphasis is used in FM transmitters to improve the signal-to-noise ratio of A. High modulating frequencies B. Low modulating frequencies C. All modulating frequencies D. Frequencies carrier 199. The result of cross-modulation is that A. The modulation of an unwanted signal is heard on the desired signal B. A decrease in modulation level of transmitted signals C. Of receiver quieting D. Of inverting sidebands in the final stage of the amplifier 200. Which of the following contains de-emphasis circuit? A. FM transmitter B. FM receiver C. VHF transmitter D. VHF receiver 201. What is emission F3F? A. AM B. Facsimile C. Television D. RTTY 202. What type of emission is produced when a frequency modulated transmitter is modulated by a facsimile signal? A. F3C B. A3C C. F3F D. A3F 203. Two AM transmitting antennas are close together. As a result the two modulated signals are mixed in the final RF stage of both transmitters. What is the resultant effect on other station? A. Harmonic interference B. Intermodulation interference C. Spurious interference D. Crossmodulation interference 204. The term used to refer to the reduction of receiver gain caused by the signal of a nearby station transmitter in the same frequency band? A. Quieting B. Cross-modulation interference C. Squelch gain rollback D. Desensitizing

205.

What is the bandwidth occupied by the carrier, both sidebands and harmonics? A. Authorized bandwidth B. Bandwidth of emission and occupied bandwidth C. Operating bandwidth D. All of these 206. A class-C RF amplifier is collector amplitude modulated and its average dc level collector current does not change. This means A. A normal condition B. Excessive drive to the base C. Insufficient drive to the base D. Insufficient audio modulation 207. What determines the percentage modulation of an FM transmitter? A. Amplitude of the carrier B. Modulating frequency C. Carrier frequency D. Amplitude of the modulating signal 208. Deviation ratio of an FM transmitter is the ratio of the A. Maximum frequency swing to the highest modulating frequency B. Operating frequency of the assigned frequency C. Frequency swing to the modulating frequency D. Highest modulating frequency to the minimum frequency 209. The main purpose of the beat frequency oscillator (BFO) is to generate A. A 1 kHz not for Morse reception B. Aid in the reception of weak voice-modulated signals C. An output, whose frequency differs from the IF by 1 kHz D. A signal, whose frequency is the same as intermediate frequency 210. Normally, a linear class BRF power amplifier operates with a bias approximately equal to A. Twice cut-off B. Ten times cut-off value C. 50% of cut-off value D. Projected cut-off 211. The purpose why an RF amplifier is operated under linear class-B conditions (as opposed to class-C) is to A. Generate only even harmonics B. Generate only odd harmonics C. Increase the efficiency D. Amplify of an AM signal 212. The term used to refer to the condition where the signal from a very strong station are superimposed on other signal being received. A. Cross-modulation interference

B. Intermodulation distoriotion C. Receiver quieting D. Capture effect 213. _________ is the amplitude of the maximum negative excursion of a signal as viewed on an oscilloscope. A. Peak-to-peak voltage B. Inverse peak positive voltage C. RMS voltage D. Peak negative voltage 214. The type of emission that suffer most from selective fading. A. CW and SSB B. SSB and TV C. FM and double sideband AM D. SSTV and CW 215. In an FM-phone signal, ________ is the ratio between the actual frequency deviation to the maximum frequency deviation. A. FM compressibility B. Modulating index C. Percentage of modulation D. Quieting index 216. _______ is used to refer to the reception blockage of one FM-phone signal by another FM-phone signal. A. Capture effect B. Desensitization C. Cross-modulation interference D. Frequency discrimination 217. A receiver selectivity of 10 kHz in the IF circuitry is optimum for what type of singals? A. SSB voice B. Facsimile C. FM D. Double-sideband AM 218. If the envelope of modulation is constant in amplitude this means A. Zero beat B. Under-modulation C. Zero-modulation D. Over-modulation 219. What is the approximate bandwidth of an FM with a modulation factor of 12.5 and a modulating frequency of 10 kHz? A. 20 kHz B. 270 kHz

C. 250 kHz D. 45 kHz 220. Amplitude modulation is the same as A. Linear mixing B. Analog multiplication C. Signal summation D. Multiplexing 221. The negative half of the AM wave is supplied by a/an _______ on a diode modulator. A. The tuned circuit B. Transformer C. Capacitor D. Inductor 222. One of the following can produce AM. A. Having the carrier vary a resistance B. Having the modulating signal vary a capacitance C. Varying the carrier frequency D. Varying the gain of an amplifier 223. Amplitude modulators that vary the carrier amplitude with the modulating signal by passing it through an attenuator network is the principle of A. Rectification B. Amplification C. Variable resistance D. Absorption 224. Which component is used to produce AM at very high frequencies? A. Varactor diode B. Thermistor C. Cavity resonator D. PIN diode 225. A collector modulator has a supply voltage of 48 V. What is the peak-to-peak amplitude of the modulating signal for 100 percent modulation? A. 24 V B. 48 V C. 96 V D. 120 V 226. What circuit recovers the original modulating information from an AM signal? A. Modulator B. Demodulator C. Mixer D. Crystal set 227. What is the most commonly used amplitude demodulator?

A. B. C. D.

Envelope detector Balanced modulator Mixer Crystal set 228. What circuit generates the upper and lower sidebands and suppresses the carrier? A. Amplitude modulator B. Diode detector C. Class C amplifier D. Balanced modulator 229. _________ is a widely used balanced modulator. A. Diode bridge circuit B. Full-wave bridge rectifier C. Lattice modulator D. Balanced bridge modulator 230. In a diode ring modulator, the diodes act like A. Variable resistors B. Switches C. Rectifiers D. Variable capacitors 231. The output of a balanced modulator is A. AM B. FM C. SSB D. DSB 232. The principal circuit in the popular 1496/1596 IC balanced modulator is a A. Differential amplifier B. Rectifier C. Bridge D. Constant current source 233. The most commonly used filter in SSB generators uses A. LC networks B. Mechanical resonators C. Crystals D. RC networks and op amps 234. In the phasing method of SSB generation, one sideband is canceled out due to A. Phase shifting B. Sharp selectivity C. Carrier suppression D. Phase inversion 235. A balanced modulator used to demodulate a SSB signal is call a/an

A. B. C. D.

Transponder Product detector Converter Remodulator 236. Frequency translation is done with a circuit called a A. Summer B. Multiplier C. Divider D. Mixer 237. Mixing for frequency conversion is the same as A. Rectification B. AM C. Linear summing D. Filtering 238. Which of the following is not a major advantage of FM over AM? A. Greater efficiency B. Noise immunity C. Capture effect D. Lower complexity and cost 239. The primary disadvantage of FM is its A. Higher cost and complexity B. Excessive use of spectrum space C. Noise susceptibility D. Lower efficiency 240. Noise is primarily A. High-frequency spikes B. Lowe-frequency variations C. Random level shifts D. Random frequency variations 241. The receiver circuit that rids FM of noise is the A. Modulator B. Demodulator C. Limiter D. Low-pass filter 242. The AM signals generated at a low level may only be amplified by what type of amplifier? A. Class A B. Class B C. Class C D. All of the above

243.

SSB means A. Single sideband with suppressed carrier B. Single sideband with carrier C. Double sideband with no carrier D. Single sideband with reduced carrier 244. A circuit used to select the desired output from a mixer A. Transformer B. Resonant circuit C. Filter D. Phase-shift circuit 245. What is the output of a balanced modulator? A. AM B. DSB C. SSB D. ISB 246. The acronym SSSC refer to A. Suppressed sideband, single carrier B. Suppressed sideband, suppressed carrier C. Single sideband, suppressed carrier D. Single sideband, single carrier 247. Which process occurs in the receiver? A. Demodulation B. Reception C. Modulation D. Recreation 248. What is usually used to demodulate SSB or CW signal? A. PLL B. BFO C. Ratio detector D. All of these 249. Which of the following is the most widely used amplitude modulator A. Diode detector B. PLL circuit C. VCO D. All of these 250. Which of the following is the most widely used balanced modulator A. Full-wave bridge circuit B. Balanced bridge modulator C. Lattice modulator D. None of these

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