MULTIPLE CHOICE QUESTIONS IN ELECTRONICS SYSTEMS AND TECHNOLOGIES TECHNOLOGIES (EST)
Digital and Data Communications MELVIN C. ARCEO, ECE PERC DC
1. It is defined as knowledge or intelligence that is communicated between two or more points. a. Carrier b. Sideband c. Information d. Broadband 2. What is the category of data transmission if the binary pulse is maintained for the entire bit time? a. Return to zero b. Bipolar c. Unipolar d. Non – Non – return return to zero 3. Which medium is the most widely used in LANs? a. Twin Lead b. Fiber – optic – optic cable c. Twisted Pair d. Coax 4. These are used for transmission of PCM encoded time – time – division multiplexed digital signal. a. I carriers b. E carriers c. A carriers d. T carriers 5. Which of the following is not a typical FDM application? a. Telemetry b. Stereo broadcasting c. Telephone d. Secure communications 6. A LAN device that is used to interconnect two networks that use different protocols and formats. a. Gateways b. Routers c. Bridges d. Hubs 7. A pulse modulation technique as the width of a constant amplitude pulse is varied proportional to the amplitude of the analog signal at the time the signal is sampled. a. Pulse Width Modulation b. Pulse Length Modulation
c. Pulse Duration Modulation d. All of these 8. The FDM telephone systems accommodate many channels by a. Increasing the multiplexer size b. Using many final carriers c. Narrowing the bandwidth of each d. Using multiple levels of multiplexing 9. It is the transmittal of digitally modulated analog signals (carrier) between two or more points in a communications system. system. a. Digital modulation b. Digital transmission c. Data communications d. Pulse modulation 10. Indicate which of the following systems is digital. a. Pulse-position modulation b. Pulse-code modulation c. Pulse – width width modulation d. Pulse-frequency modulation 11. Classification of protocol that interprets a frame of data as a group of successive bit combined into predetermined pattern of fixed length, usually 8 bits each. a. Character-oriented protocols b. Byte-oriented protocols c. Bit-oriented protocols d. Character and Byte-oriented protocols 12. Dividing the data block by a constant produces a remainder that is used for error detection. It is called the a. Vertical redundancy check b. Horizontal redundancy check c. Block check character d. Cyclic redundancy check 13. Which of the following is not a benefit of spread spectrum? a. Jam – Jam – proof proof b. Security c. Immunity of fading d. Noise proof
14. Converting analog signals to digital is done by sampling and ___________. a. Quantizing b. Companding c. Pre – Pre – emphasis emphasis d. Mixing 15. It is a process of converting an infinite number of possibilities to a finite number of conditions. a. Sampling b. Coding c. Quantization d. Aliasing 16. In T1, it is equal to the reciprocal of the sample rate a. Slot Time b. Transmission Transmission time c. Frame time d. Bit rate 17. What is the final output of a multiplexer? a. Baseband b. Composite baseband c. Information d. Composite carrier 18. The baud rate a. is always equal to the bit transfer rate b. is equal to twice the bandwidth of an ideal channel c. is not equal to the signaling rate d. is equal to one – half the bandwidth of an ideal channel 19. Bit errors in data transmission are usually caused by a. equipment failures b. typing mistakes c. noise d. poor S/N ratio at receiver 20. A digital modulation technique which is a form of constant – amplitude angle modulation similar to standard frequency modulation except the modulating signal is binary signal that varies between two discreet voltage levels. a. QAM b. ASK c. PSK
d. FSK
21. Start and stop bits, respectively, are a. Mark, space b. Space, mark c. Space, space d. Mark, mark 22. It is the processing of analog signals using digital methods and includes band limiting and signals with filters, amplitude equalization, and phase shifting a. Digital communications b. Digital Signal Processing c. Data communications d. Carrier recovery method 23. It is a network access method used primarily with LANs configured in a ring topology using either baseband or broadband transmission transmission formats a. Ethernet b. Token passing c. Token ring d. Token bus 24. A small telephone switching system that can be used as a LAN is called a. Ring b. WAN c. UART d. PBX 25. The most common method used sampling voice signals in PCM systems a. unnatural sampling b. flat top sampling c. natural sampling d. free sampling
for
26. In PCM, it converts the PAM sampled to parallel PCM codes a. Analog-to-Digital converter b. Digital-to-analog converter c. Pre-emphasis circuit d. Compander 27. The OSI layer that provides the control functions necessary to establish, manage and terminated the connections as required to satisfy the user request. a. Application layer
b. Network layer c. Session layer d. Physical layer 28. In PAM demultiplexing, the receiver clock is derived from a. standard radio station WWV b. a highly accurate internal oscillator c. the PAM signal itself d. the 60 Hertz power line 29. It is also known as digital modulation a. Digital transmission b. Digital sampling c. Digital radio d. Data transmission 30. Time – division multiplex a. can be used with PCM only b. combines five groups into supergroup c. stacks 24 channels in adjacent frequency slots d. interleaves pulses belonging to different transmissions 31. It is a numerical indication efficiently a PCM code is utilized a. Coding efficiency b. Companding c. Pre-emphasis d. Dynamic Range
of
input is binary digital signal and there are limited numbers of output phase possible. a. ASK b. PSK c. FSK d. QAM 35. The main circuit in a PSN generator is ____. a. XOR b. Multiplexer c. Shift register d. Mixer 36. The circuit that performs demultiplexing in an FDM system is _____. a. Op - Amp b. Bandpass filter c. Discriminator d. Subcarrier oscillator 37. __________ defines how a user gets control of the channel so as to allow transmission. a. channel access b. collision detection c. collision avoidance d. carrier sense
how
32. Type of PCM which is designed to take advantage of the sample-to-sample redundancies in the typical speech waveform a. Single – bit PCM code b. Pulse Code Modulation c. Differential PCM d. Delta modulation 33. The Basic Rate Interface (BRI) of ISDN has a total bit rate of _____. a. 192 kbps b. 148 kbps c. 64 kbps d. 1.544 Mbps 34. A form of angle – modulated, constant amplitude digital modulation similar to conventional phase modulation except its
38. The fastest LAN topology is the a. ring b. bus c. star d. square 39. It is a the symmetrical expectation of the bit error rate in the system a. probability of errors b. error detection c. error control d. bit error rate 40. It is simply the data rate at which serial PCM bits are clocked out of the PCM encoder onto the transmission line. a. line speed b. baud rate c. output rate d. bit rate 41. A quantizing is _______. a. Multiplexer b. Demultiplexer c. A/D converter
d. D/A converter 42. Refers to the rate of change of a signal on a transmission medium after encoding and modulation have occurred a. baud rate b. phase shift c. bit rate d. frequency deviation 43. The magnitude difference between adjacent steps in quantization is called __________. a. Quantum b. Step size c. Resolution d. Any of these 44. It is a set of rules implementing and governing an orderly exchange of data between layers of two devices, such as line control units and front – end processors. a. Data Link Protocol b. Network Protocol c. Point to Point Protocol d. File Transfer Protocol 45. A signaling system in which each letter of the alphabet is represented by a different symbol is not used because a. it would be too difficult for an operator to memorize b. it is redundant c. noise would introduce too many errors d. too many pulses per letter are required 46. A modulation process that involves conversion of a waveform from analog to digital form by means of coding. a. PDM b. PCM c. PLM d. PAM 47. What is the bandwidth required to transmit at a rate of 10 Mbps in the presence of a 28 bd S/N ratio? a. 1.075 MHz b. 10 Mhz c. 5 Mhz d. 10.5 Mhz
48. The slope of the analog signal is greater than the delta modulator can maintain a. overload distortion b. granular noise c. slope overload d. peak limiting 49. A scheme in which several channels are interleaved and then transmitted together is known as a. Frequency division multiplex b. Time division multiplex c. a group d. a supergroup 50. The best frequency demodulator is the a. PLL discriminator b. Pulse-averaging discriminator c. Foster-Seeley discriminator d. Radio detector 51. What property distinguishes digital radio systems from conventional analog communications system? a. the type of carrier used in the transmission of data b. the nature of the modulating signal c. the type of modulation of data to be used d. the nature of the transmitter and receiver to be used 52. The circuit switch is a _______ switch. a. See – through b. Transparent c. Vague d. Opaque 53. A carrier recovery is needed with a. FSK b. BPSK c. DPSK d. QAM 54. The Hartley – Shannon theorem sets a limit on the a. highest frequency that may be sent over a given channel b. maximum capacity of a channel with a given noise level c. maximum number of coding levels in a channel with a given noise level
d. maximum number of quantizing levels in a channel of a given bandwidth 55. The phase relationship between signaling elements for BPSK is the optimum signaling format and occurs only when two binary signal levels are allowed and when one signal is the exact negative of the other. a. Antipodal signaling b. Carrier recovery c. Squaring loop d. Phase referencing 56. Pulse – amplitude modulation signals are multiplexed by using a. Subcarrier b. Bandpass filters c. A/D converters d. FET switches 57. It is the ratio of the transmission bit rate to the minimum bandwidth required for a particular modulation scheme. a. Bandwidth efficiency b. All of these c. Information density d. Spectral efficiency 58. Ethernet is baseband transmission system designed by _____. a. Thomas Murray and Robert Metcalfe b. David Boggs and Thomas Murray c. Thomas Murray and Emile Baudot d. Robert Metcalfe and David Boggs 59. It is a system where the digital signals are placed directly on the coaxial cable. a. Broadband b. Baseband c. CSMA/CD d. Token ring 60. A basic group B a. Occupies the frequency range from 60 to 108 kHz b. Consists of erect channels only c. Is formed at the group translating equipment d. Consists of 5 supergroups
61. Which of the following is not primarily type of data communications? a. a telephone b. teletype c. telegraph d. CW 62. Packets which is self – contained and travels through the network independent of other packets of the same message by whatever means available. a. Packet b. Frame c. Datagram d. Data 63. Transmitting the data signal directly over the medium is referred to as a. baseband b. broadband c. ring d. bus 64. The main reason that serial transmission is preferred to parallel transmission is that? a. serial is faster b. serial requires only a single channel c. serial requires multiple channels d. parallel is too expensive 65. Which of the following is not a LAN? a. PBX system b. Hospital system c. Office building system d. Cable TV system 66. A modulation technique where data rates in excess of 56 kbps can be achieved over telephone circuits a. ASK b. Trellis Code Modulation c. GSK d. Any of these 67. It is how the primary designates the secondary as the designation of recipient of data. a. Line turnaround b. Selection c. Line control d. Control Protocol
68. It is the process of compressing and expanding and is a means of improving the dynamic range of communications system. a. Pre-emphasis b. Filtering c. De-emphasis d. Companding 69. The supergroup pilot is a. applied to each multiplexing bay b. used to regulate the gain of individual repeaters c. applied at each adjustable equalizer d. fed in at a GTE 70. The time it takes to transmit one TDM frame is called _________. a. Slot time b. Frame time c. Transmission time d. Any of these 71. It is the thermal noise power normalized to 1-Hz bandwidth a. power density ratio b. thermal noise c. noise power density d. ambient temperature noise 72. It is the procedure used to decide which device has the permission to transmit at any given time a. Flow control b. Sequence control c. Line control d. Framing 73. Any rounded – off errors in the transmitted signal are reproduced when the code is converted back to analog in the receiver. a. Aperture error b. Quantization error c. Aperture distortion d. Slope overload 74. The biggest disadvantage of PCM is a. its inability to handle analog signals b. the high error rate which is quantizing noise introduces c. its incompatibility with TDM d. the large bandwidths that are required for it
75. T1 stands for a. Transmission one b. Telecommunication one c. Telex one d. Transmission line one 76. Involves compression in the transmitter after the input sample has been converted to a linear PCM code and then expansion in the receiver prior to PCM coding a. analog companding b. A – law companding c. Digital companding d. U – law companding 77. Mark and space refer respectively to a. dot and dash b. message and interval c. binary 1 and binary 0 d. on and off 78. Variation of biphase that is used for encoding SMPTE time code data and for recording on video tapes a. Biphase - M b. B8Z c. Manchester d. UPNRZ 79. Pulse width modulation may be generated a. by differentiating pulse position modulation b. with a monostable multivibrator c. by integrating the signal d. with a free running multivibrator 80. The ISDN channel D designates _____ which contains control information. a. Data b. Flow c. Control d. Bearer 81. A transmission of binary data which involves the transmission of two non – zero voltage level a. Unipolar b. Polar c. Bipolar d. Non – return to zero
82. Switching systems a. improve the efficiency of data transfer b. are not used in data systems c. require additional lines d. are limited to small data networks 83. It involves converting standard logic levels to a form more suitable to telephone transmission lines a. Transmission line encoding b. Physical line encoding c. Digital line encoding d. Multiplexing 84. The primary advantage transmission a. economical b. reliability c. noise immunity d. efficiency
of
digital
85. Part of the PCM system that prevents aliasing or foldover distortion a. Bandpass filter b. Anti – foldover distortion c. Anti – aliasing d. Any of these
89. An IC that contains A/D and D/A converters, companders, and parallel-toserial converters is called a a. Codec b. Data converter c. Multiplexer d. Modem 90. Data communications transmission of a. voice b. video c. computer data d. all of the above
refers
to
the
91. The number of amplitude, frequency, or phase changes that take place per second is known as the a. data rate in bits per second b. frequency of operation c. speed limit d. baud rate 92. The basic modulator and circuits in PSK are a. PLLs b. Balanced modulators c. Shift registers d. Linear summers
demodulator
86. It is defined as the process of transforming messages or signals in accordance with a definite set of rules. a. Quantizing b. Sampling c. Coding d. Decoding
93. What is the result if the input of ADC is changing while performing conversion? a. Aperture error b. Overload distortion c. Aliasing d. Aperture distortion
87. The PCM code for each channel occupies a fixed time slot called a. Frame time b. Baud c. Transmission time d. Epoch
94. Information capacity is convenient express as a. baud b. bits c. dot length d. bits per second or bps
88. The building block of a parity or BCC generator is _________. a. Shift register b. XOR c. 2 – to – 4 level converter d. UART
95. Which noise? a. b. c. d.
to
medium is the least susceptible to twin lead fiber – optic cable twisted pair coax
96. The RS – 232 interface a. interconnects data sets and the transmission circuits b. uses several different connectors c. permits custom wiring of signal lines to the connector pins as desired d. all of the above 97. The ISDN channel B designates _________. a. Bearer b. Data c. Control d. Flow 98. Data transmission of the character at a time with start and stop bits is known as what type of transmission? a. asynchronous b. serial c. synchronous d. parallel 99. Sampling technique that when the tops of the sample pulses retain their natural shape during the sample interval a. unnatural sampling b. flat top sampling c. natural sampling d. free sampling 100. A modem converts a. Analog signals to digital b. Digital signals to analog c. Digital signals to analog and viceversa d. None of these
101. It is a large scale integration chip designed for use in telecommunication industry for private branch exchanges, central office switches, digital handsets and digital echo suppressors. a. Vocoder b. Modem c. Codec d. Muldem 102. What is the type of mastergroup used for low – capacity microwave systems? a. A600 b. U600
c. L600 d. L400
103. An FDM hierarchy which is formed by frequency – division multiplexing five groups containing 12 channels each for a combined bandwidth of 240 kHz. a. Supergroup b. Group c. Mastergroup d. Jumbogroup 104. The result whenever the sampling rate is less than twice the highest audio frequency a. peak limiting b. overload distortion c. alias d. quantizing noise 105. The most critical and difficult part of receiving a direct – sequence spread spectrum signal is a. Frequency synthesis b. Synchronism c. PSN code generation d. Carrier recovery 106. An FDM hierarchy which is formed by frequency – division multiplexing 10 super groups together for a combined capacity of 600 voice band message channels a. Supergroup b. Group c. Mastergroup d. Jumbogroup 107. It is the transmittal of digital signals between to or more points in a communication system. a. Digital transmittal b. Digital communications c. Digital radio d. Data communications 108. It is logically equivalent to making telephone call through the DDD network except no direct end-to-end connection is made a. Normal call b. Completed call c. Logical call d. Virtual call
109. It is proposed network designed by major telephone companies in conjunction with the ITU-T with the intent of providing worldwide telecommunications support for voice, data, video and facsimile information within the same network a. ISDN b. Broadband communications c. ATM d. Ethernet 110. Full duplex operation a. requires two pair of cables b. can transfer data in both directions at once c. requires modems at both ends of the circuit d. all of these 111. The most widely communications code is a. Morse code b. ASCII c. Baudot d. EBCDIC
used
data
112. Ten bit error occurs in two million transmitted. The bit error rate is a. 2 x 10^-5 b. 5 x 10^-5 c. 5 x 10^-6 d. 2 x 10^-6 113. It is a type of FSK where the mark and space frequencies are synchronized with the input binary rate a. QFSK b. GFSK c. CPFSK d. GSK 114. A form of digital modulation similar to PSK except the digital information is contained in both the amplitude and the phase of the transmitted carrier. a. ASK b. FSK c. QAM d. PSK
115. For the 16-PSK and a transmission system with a 10kHz bandwidth, determine the maximum bit rate a. 40,000 bps b. 80,000 bps c. 20,000 bps d. 16,000 bps 116. It is an empirical record of a system’s actual bit error performance. a. probability of error b. error detection c. error control d. bit error rate 117. It is a function of the carrier-to-noise power ratio and the number of possible encoding conditions used a. probability of error b. error detection c. error control d. bit error rate 118. It is used to compare two or more digital modulation systems that use different transmission rates, modulation scheme or encoding techniques a. Energy per b it-to-noise power density ratio b. Noise power density c. Power density ratio d. Carrier-to-noise ratio 119. Indicate which of the following is not a binary code a. Morse b. Baudot c. CCITT-2 d. ARQ 120. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is a. 2 b. log 16 base 10 c. 8 d. 4 121. The type of modulation most often used with direct-sequence spread spectrum is a. QAM b. SSB
c. FSK d. PSK 122. Indicate the false statement. In order to combat noise, a. the channel bandwidth may be increased b. redundancy may be used c. the transmitted power may be increased d. the signaling rate may be reduced 123. Which of the following is not commonly used method of error detection? a. Parity b. BCC c. CRC d. redundancy 124. Quantizing noise occurs in a. time-division multiplex b. frequency-division multiplex c. pulse-code modulation d. pulse-width modulation 125. In order to reduce quantizing noise, one must a. increase the number of standard amplitudes b. send pulses whose sides are more nearly vertical c. use an RF amplifier at the receiver d. increase the number of samples per second 126. Companding is used a. to overcome quantizing noise in PCM b. in PCM transmitters, to allow amplitude limiting in the receiver c. to protect small signals in PCM form quantizing distortion d. in PCM receivers, to overcome impulse noise 127. Transmitting data as serial binary word is called _______. a. digital communications b. quantizing c. PAM d. PCM
128. Emphasizing low-level signals and compressing higher level signals is called a. quantizing b. companding c. pre-emphasis d. sampling 129. Which circuit is most common to both frequency-hopping and direct-sequence spread spectrum transmitters? a. correlator b. frequency synthesizer c. PSN code generator d. Sweep generator 130. One of the most important aspect of any communication system because it is costly and limited a. bandwidth b. equipments c. time d. personnel 131. It consist essentially of sampling analog information signals and then converting those samples into discreet pulses of transporting the pulses from the source to destination over a physical transmission medium a. Pulse modulation b. Amplitude modulation c. Frequency modulation d. Digital modulation 132. He is credited with inventing PCM in 1937 a. N. S. Kapany b. A. H. Reeves c. E. H. Alpine d. A. C. S. Van Heel 133. Data communications uses a. Analog methods b. Digital methods c. All of these d. None of these 134. An integrated circuit that performs the PCM encoding and decoding functions a. Codec b. Modem c. Muldem d. Digital-to-analog converter
135. A synchronous transmission begins with which character? a. SYN b. STX c. SOH d. ETB
usually
136. A theory that establishes the minimum sampling rate that can be used for a given PCM systems a. Nyquist sampling theorem b. Nyquist minimum bandwidth c. Nyquist minimum bandwidth d. Any of these 137. Sixteen different levels (symbols) are used to encode binary data. The channel bandwidth is 36 MHz. The maximum channel capacity is a. 18 Mbps b. 72 Mbps c. 288 Mbps d. 2.176 Gbps 138. Assigning PCM magnitudes a. Coding b. Quantizing c. Sampling d. Any of these
codes
to
142. What is the minimum bandwidth required to transmit a 56 kbps binary signal with no noise? a. 14 kHz b. 56 kHz c. 28 kHz d. 112 kHz 143. Type of PCM that uses single-bit PCM code to achieve digital transmission of analog signals a. Adaptive delta modulation b. Pulse code modulation c. Differential modulation d. Delta modulation 144. It is a delta modulation system where the step size of the digital-to-analog converter is automatically varied, depending on the analog input signal. a. Adaptive Delta Modulation b. PCM c. Differential modulation d. Delta modulation
absolute
139. A popular PC protocol is a. Parity b. Xmodem c. CRC d. LRC 140. It is the ratio of the largest possible magnitude to the smallest possible magnitude that can be decoded by the digital-to-analog converter in the receiver a. Coding efficiency b. Companding c. Pre-emphasis d. Dynamic range 141. Devices used for digitizing speech signals only a. codec b. muldem c. vocoders d. modem
145. A QAM modulator does not use ____. a. XNOR b. Bit Splitter c. Balanced modulator d. 2-to-4 level converter 146. It is a form of phase-division multiplexing where two data channels modulate the same carrier frequency that is shifted 90 degrees in phase. a. PSK b. FSK c. QAM d. ASK 147. One eight-bit PCM code is called ______. a. FDM frame b. TDM time slot c. TDM frame d. FDM time slot 148. It is communications system that uses digital pulse rather than analog signals to encode information a. Digital carrier system b. Digital baseband system c. Digital service system
d. Digital broadband system 149. A special device that upgrades signals from one level to a higher level of the hierarchy in multiplexing a. Muldem b. Vocoder c. Modem d. Codec 150. A transmission of binary data which involves the transmission of only a single non-zero voltage level. a. Unipolar b. Bipolar c. Polar d. Non-return to zero
MULTIPLE CHOICE QUESTIONS IN ELECTRONICS SYSTEMS AND TECHNOLOGIES (EST)
Antennas MELVIN C. ARCEO, ECE PERC DC
ENCODED BY: BADILLO, AIMIE E. 2006105942 ECE003/C11
1. It is a metallic conductor system capable of radiating and capturing electromagnetic energy a. transmission lines b. antenna c. waveguides d. load
8. Electrical energy that has escaped into free space in the form of transverse electromagnetic waves a. Radio waves b. Frequency c. Signal d. Wavelength
2. A directional antenna with two or more elements is known as a. folded dipole b. ground plane c. loop d. array
9. The length of the ground plane vertical at 146 MHz is a. 1.6 ft b. 1.68 ft c. 2.05 ft d. 3.37 ft
3. The ratio of the focal length to the diameter of the mouth of the parabo la is called _____. a. aperture b. focal point c. foci d. major axis
10. Using a small reflector to beam waves to the larger parabolic reflector is known as a. Focal feed b. Horn feed c. Cassegrain feed d. Coax feed
4. The impedance of a dipole is about a. 50-ohm b. 73-ohm c. 93-ohm d. 300-ohm
11. The plane parallel to the mutually perpendicular line in the electric and magnetic fields is called _______. a. wavefront b. point source c. isotropic source d. rays
5. A special type of transmission line that consist of conducting metallic tube through which high frequency electromagnetic energy is propagated a. medium b. microstrip c. stripline d. waveguide
12. What is the beamwidth of a parabolic antenna with a diameter of 5 meters and an operating frequency of 10 GHz? a. 0.5 degrees b. 0.675 degrees c. 0.348 degrees d. 3.48 degrees
6. Calculate the angle of declination for an antenna using a polar mount at a latitude of 45 degrees a. 3.2 degrees b. 1.3 degrees c. 4.2 degrees d. 6.81 degrees
13. The horizontal radiation pattern of a dipole is a a. circle b. figure of eight c. clover leaf d. narrow beam
7. The cone angle of the flare angle of a conical horn antenna is approximately a. 55 degrees b. 45 degrees c. 40 degrees d. 50 degrees
14. The size of antenna is inversely proportional to _______. a. frequency b. power c. radiation resistance d. wavelength
15. A popular half – wave antenna is the a. Ground plane b. End-fire c. Collinear d. Dipole 16. Calculate the gain of a parabolic antenna using a 2.5-m radius dish operating at 10GHz. a. 166.673 dB b. 83.7 dB c. 52.2 dB d. 45.6 dB 17. It is the ratio of the radiated to the reflected energy a. Radiation resistance b. Radiation efficiency c. Radiation constant d. Radiation antenna 18. The feed mechanism in a parabolic antenna that radiates the electromagnetic energy. a. Primary antenna b. Reflectors c. Secondary antenna d. Focal point 19. It is a polar diagram or graph representing field strengths or power densities at various angular positions relative to an antenna a. Side lobe b. Front lobe c. Radiation pattern d. Radiation constant 20. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directive gain of 20 and an input power of 100W, determine the antenna gain. a. 12.55 dB b. 10.43 dB c. 11.21 dB d. 9.78 dB 21. The radiation pattern plotted in terms of electric field strength or power density a. absolute radiation pattern b. relative radiation pattern c. absolute front lobe pattern d. absolute side lobe pattern
22. Calculate the characteristic impedance of a quarter – wavelength section used to connect a 300-ohm antenna to a 75-ohm line a. 150 ohms b. 120 ohms c. 130 ohms d. 110 ohms 23. Plots of field strength or power density with respect to the value at a reference point a. absolute front lobe pattern b. relative front lobe pattern c. relative front lobe pattern d. relative radiation pattern 24. What must be the height of a vertical radiator one half wavelength high if the operating frequency is 1100 kHz? a. 120 m b. 136 m c. 115 m d. 124 m 25. Lobes adjacent to the front lobe a. Diagonal lobes b. Side lobes c. Front lobes d. Back lobes 26. Lobes in a direction exactly opposite of the front lobe a. Side lobes b. Adjacent lobes c. Front lobes d. Back lobes 27. Calculate the efficiency of an antenna that has a radiation resistance of 73 ohms and an effective dissipation resistance of 5 ohms a. 98.3% b. 93.6% c. 90.7% d. 95.5% 28. The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _______. a. line of shoot b. diagonal shoot c. bisecting shoot d. antenna shoot
29. The ammeter connected at the base of a Marconi antenna has a certain reading. If this reading is increased 2.77 times, what is the increase in output power? a. 3.45 b. 1.89 c. 2.35 d. 7.67 30. Refers to a field pattern that is close to the antenna. a. Induction field b. Far field c. Radiation field d. Capture field 31. A half-wave dipole is driven with a 5-W signal at 225 MHz. A receiving dipole 100 km. Calculate the received power into a 73ohm receiver. a. 23.5 pW b. 7.57 pW c. 5.64 pW d. 1.26 pW 32. It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates. a. Directive gain b. Antenna efficiency c. Radiation resistance d. Antenna resistance 33. What is the effective radiated power of a television broadcast station if the output of the transmitter is 1000W, antenna transmission line loss is 50W, and the antenna power gain is 3? a. 1250 W b. 2370 W c. 2130 W d. 2850 W 34. It is the ratio of the power radiated by an antenna to the sum of the power radiated and the power dissipated. a. radiation resistance b. coupling coefficient c. antenna efficiency d. antenna beamwidth
35. It is the ratio of the power radiated by the antenna to the total input power. a. antenna efficiency b. reflection coefficient c. standing wave ratio d. radiation resistance 36. If a 500 kHz transmitter of a constant power produces field strength of 100uV/m at a distance of 100 mi from the transmitter, what would be the theoretical field strength at a distance of 200 mi from the transmitter? a. 45 uV/m b. 100 uV/m c. 50 uV/m d. 35 uV/m 37. An antenna that transmits or receives equally well in all directions is said to be _____. a. omnidirectional b. bidirectional c. unidirectional d. quasidirectional 38. It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power a. power gain b. directive gain c. total gain d. system gain 39. If the field intensity of 25 mV/m develops 2.7 V in a certain antenna, what is its effective height? a. 110 m b. 100 m c. 98 m d. 108 m 40. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization ______. a. is vertical b. is horizontal c. is circular d. cannot be determined from the information given
41. If the power of a 500 kHz transmitter is increased from 150 W to 300 W, what would be the percentage change in field intensity at a given distance from the transmitter? a. 141% b. 150% c. 100% d. 133% 42. It is the same with directive gain except that the total power fed to the antenna is used and the antenna efficiency is taken into account. a. system gain b. power gain c. directive gain d. total gain 43. A hip-radio telephone transmitter operates on 2738 kHz. At a certain point distant from the transmitter, the 2738 kHz signal is measured field of 147 mV/m. The second harmonic field at the same point is measured as 405 uV/m. To the nearest whole unit in decibels, how much has the harmonic emission been attenuated below the 2738 kHz fundamental? a. 43.2 dB b. 51.2 dB c. 35.1 dB d. 25.1 dB 44. It is the equivalent power that an isotropic antenna would have to radiate to achieve the same power density in the chosen direction at a given point as another antenna. a. EIRP b. ERP c. IRL d. RSL 45. When the energy is applied to the antenna at a point of high – circulating current. a. voltage-fed antenna b. power-fed antenna c. current-fed antenna d. impedance-fed antenna 46. For a transmit antenna with a power gain of 10 and an input power of 100W, determine the EIRP in watts.
a. b. c. d.
30 dBW 40 dBW 50 dBW 20 dBW
47. If energy is applied at the geometrical center of antenna, the antenna is said to be _____. a. center-fed b. end-fed c. quarterwave-fed d. halfwave-fed 48. For a transmit antenna with a power gain of 10 and an input power of 100W, determine the power density at a point 10 km from the transmit antenna a. 0.574 uW/m^2 b. 0.796 uW/m^2 c. 1.24 uW/m^2 d. 0.981 uW/m^2 49. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directive gain of 20 and an input power of 100W, determine the antenna efficiency. a. 90% b. 96% c. 98% d. 96% 50. The fields surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out in space. a. induction field b. near field c. radiation field d. magnetic field 51. For receive power density of 10 uW/m^2 and a receive antenna with a capture area of 0.2 m^2, determine the captured power. a. 0.5 uW b. 2 uW c. 1 uW d. 1.5 uW 52. The property of interchangeability for the transmitting and receiving operations is known as ______. a. efficiency b. accuracy
c. reciprocity d. polarization
53. The length of a doublet at 27 MHz is _____. a. 8.67 ft b. 17.3 ft c. 18.2 ft d. 34.67 ft 54. Refers to the orientation of the electric field radiated from an antenna. a. efficiency b. beamwidth c. polarization d. accuracy 55. At frequencies below 2 MHz, what type of antenna is usually used? a. Marconi antenna b. Hertzian antenna c. Hertz antenna d. Elementary doublet 56. The angular separation between two half power points in the major lobe of the antenna’s plane radiation pattern. a. bandwidth b. polarization c. efficiency d. beamwidth 57. Hertz antenna are predominantly used with frequencies above a. 3 MHz b. 4 MHz c. 5MHz d. 2MHz 58. Defined as the frequency range over which antenna operation is satisfactory a. beamwidth b. channel c. bandwidth d. baseband 59. One of the following omnidirectional antenna. a. Half-wave dipole b. Log-periodic c. Discone d. Marconi
is
not
an
60. The point on the antenna where the transmission line is connected is called _______. a. center feed b. end feed c. feedpoint d. voltage feed 61. A popular vertical antenna is the _____> a. collinear b. dipole c. ground plane d. broadside 62. The discone antenna is a. a useful direction-finding antenna b. used as a radar receiving antenna c. circularly polarized with other circular antennas d. useful as a UHF receiving antenna 63. The feedpoint presents and ac load to the transmission line called a. antenna output impedance b. antenna input impedance c. feedpoint impedance d. center feed impedance 64. A helical antenna is used for satellite tracking because of its a. circular polarization b. maneuverability c. broad bandwidth d. good front to back ratio 65. The simplest type of antenna. a. Elementary doublet b. Half-wave dipole c. Quarterwave dipole d. 5/8 wavelength dipole 66. Zoning is used with a dielectric antenna in order to a. reduce the bulk of the lens b. increase the bandwidth of the lens c. permit pin-point focusing d. correct the curvature of the wavefront from a horn that is too short
67. It is an electrically short dipole a. short dipole b. quarterwave dipole c. half-wave dipole d. yagi antenna
74. An antenna that is circularly polarized is the a. helical b. small circular loop c. parabolic reflector d. Yagi – Uda
68. Cassegrain feed is used with parabolic reflector to a. increase the gain of the system b. increase the bandwidth of the system c. reduce the size of the main reflector d. allow the feed to be placed at a convenient point
75. It is a wire structure placed below the antenna and erected above the ground. a. ground plane b. counterpoise c. ground lines d. top hat
69. The half-wave dipole is generally referred to as ______. a. Yagi antenna b. Hertzian antenna c. Marconi antenna d. Hertz antenna 70. Top loading is sometimes used with an antenna in order to increase its a. effective height b. bandwidth c. beamwidth d. input capacitance 71. What is the directivity of a Hertz antenna? a. 1.64 b. 2.18 c. 2.15 d. 1.75 72. The standard reference antenna for the directive gain is the _______. a. infinitesimal dipole b. isotropic antenna c. elementary doublet d. half-wave dipole 73. An antenna which is one-quarter wavelength long, mounted vertically with the lower end either connected directly to ground or grounded through the antenna coupling network. a. loop antenna b. hertzian dipole c. monopole antenna d. turnstile antenna
76. Which of the following terms does not apply to the Yagi-Uda array? a. good bandwidth b. parasitic elements c. folded dipole d. high gain 77. It effectively cancels out the capacitance component of the antenna input impedance. a. ground plane b. top hat c. loading coil d. shunt capacitance 78. Indicate which of the following reasons for the use of an earth mat with antenna is false: a. impossibility of a good ground conduction b. provision of an earth for an antenna c. protection of personnel working underneath d. improvement of the radiation pattern of the antenna 79. A metallic array that resembles a spoke wheel placed at the top of an antenna, it increases the shunt capacitance to ground reducing the overall antenna capacitance. a. loading coil b. top loading c. series capacitance d. series inductors 80. Indicate the antenna that is not wideband: a. discone b. folded dipole c. helical d. marconi
81. It is formed when two or more antenna elements are combined to form a single antenna. a. antenna elements b. antenna array c. driven elements d. parasitic elements 82. One of the following is 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 reradiation of local oscillators 83. It is an individual radiator, such as a half or quarter-wave dipole. a. antenna element b. antenna array c. reflector d. director 84. Indicate which of the following reasons for using a counterpoise with antennas is false: a. impossibility 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 85. Type of antenna element that is directly connected to the transmission lines and receives from or is driven by the source. a. driven array b. parasitic array c. driven element d. parasitic element 86. Which of the following antennas is best excited from a waveguide? a. biconical b. horn c. helical d. discone 87. Type of antenna element that is not connected to the transmission lines. a. parasitic array b. driven array
c. parasitic array d. parasitic element 88. One of the following is very useful as a multi-band HF receiving antenna. This is the: a. conical horn b. folded dipole c. log-periodic d. square loop 89. A parasitic element that is longer than the driven element from which it receives energy. a. driven element b. director c. parasitic elements d. reflector 90. One of the following consists of nonresonant antennas. a. rhombic antenna b. folded-dipole antenna c. end-fire antenna d. broadside antenna 91. A parasitic element that is shorter than its associated driven element. a. redirector b. director c. reflector d. parasitic element 92. An ungrounded antenna near the ground. a. acts as a single antenna near the ground b. is unlikely to need an earth mat c. acts as an antenna array d. must be horizontally polarized 93. It is a non-resonant antenna capable of operating satisfactorily over a relatively wide bandwidth, making it ideally suited for HF transmission. a. turnstile antenna b. loop antenna c. rhombic antenna d. discone antenna 94. A wide – bandwidth multi-element driven array is the ______. a. end-fire
b. log-periodic c. yagi d. collinear
95. It is a linear array antenna consisting of a dipole and two or more parasitic elements: one reflector and one director. a. broadside antenna b. end-fire antenna c. yagi-uda antenna d. phased array antenna 96. An antenna which is consists of a cone that is truncated in a piece of circular waveguide. a. pyramidal horn antenna b. circular horn antenna c. rectangular horn antenna d. circular horn antenna 97. Which antenna has a unidirectional radiation pattern and gain? a. dipole b. ground plane c. yagi d. collinear 98. An antenna formed by placing two dipoles at right angles to each other, 90 degrees out of phase. a. discone antenna b. turnstile antenna c. bicone antenna d. 5/8 wavelength antenna 99. The radiation pattern of collinear and a broadside antenna is ________. a. omnidirectional b. bidirectional c. unidirectional d. clover-leaf shaped 100. What is the bandwidth ration of log periodic antenna? a. 10:1 b. 5:1 c. 20:1 d. 1:10 101. Which beam width represents the best antenna directivity? a. 7 degrees b. 12 degrees
c. 19 degrees d. 28 degrees 102. It is the ratio of the highest to the lowest frequency over which an antenna will satisfactorily operate. a. channel ratio b. bandwidth ratio c. reflection ratio d. dynamic range 103. An antenna has a power gain off 15. The power applied to the antenna is 32 W. The effective radiated power is ________. a. 15 W b. 32 W c. 120 W d. 480 W 104. It is simply a single-turn coil of wire that is significantly shorter than one wavelength and carries RF current. a. turnstile antenna b. loop antenna c. rhombic antenna d. long-wire antenna 105. A coax has an attenuation of 2.4 dB per 100 ft. The attenuation of 275 ft a. 2.4 dB b. 3.3 dB c. 4.8 dB d. 6.6 dB 106. It is group of antenna arrays that when connected together, function as a simple antenna whose beamwidth and direction can be changed electronically without having to physically move any of the individual antennas or antenna elements within the array. a. end-fire array b. broadside antenna c. phased array antenna d. log-periodic antenna 107. Conductors in multi-element antennas that do not receive energy directly from the transmission line are known as ______. a. parasitic element b. driven element c. the boom
d. receptor 108. It is a broadband VHF or UHF antenna that is suited for applications for which radiating circular rather than horizontal or vertical polarized electromagnetic waves are required. a. discone antenna b. bicone antenna c. log-periodic antenna d. helical antenna 109. Mode of propagation of helical antenna where electromagnetic radiation is in the direction at right angles to the axis of the helix. a. normal mode b. axial mode c. helix mode d. helical mode 110. Mode of propagation of helical antenna where the radiation of the antenna in the axial direction and produces a broadband relatively directional pattern. a. helical mode b. normal mode c. axial mode d. helix mode 111. In a Yagi antenna, maximum direction of radiation is toward the a. director b. driven element c. reflector d. sky 112. It is defined as the ratio of the antennas maximum gain in the forward direction to its maximum gain in its backward direction a. side-to-back ratio b. front-to-side ratio c. back-to-side ratio d. front-to-back ratio 113. The horizontal radiation pattern of a vertical dipole is a ____________. a. figure of eight b. circle c. narrow beam d. clover leaf
114. An antenna that provides extremely high gain and directivity and very popular for microwave radio and satellite communications link. a. helical antenna b. parabolic antenna c. hyperbolic antenna d. log-periodic antenna 115. Part of a parabolic antenna that houses the primary antenna which radiates electromagnetic waves toward the reflector. a. feed mechanism b. focal point c. center feed d. feed antenna 116. It is a passive device that simply reflects the energy radiated by the feed mechanism into a concentrated, highly directional emission in which the individual waves are all in phase with each other. a. director b. parabolic segment c. reflector d. feed mechanism 117. The energy near the edge of the parabolic dish that does not reflect but rather is diffracted around the edge of the dish. a. spillover b. corona c. dissipated power d. copper loss 118. Determines the angular aperture of the reflector, which indirectly determines how much the primary radiation is reflected by the parabolic dish. a. numerical aperture b. V number c. aperture number d. aperture angle 119. For a 2-m diameter parabolic reflector with 10W of power radiated by the feed mechanism operating at 6 GHz with a transmit antenna efficiency of 55% and an aperture efficiency of 55%, determine the beamwidth. a. 1.25 degrees
b. 2.25 degrees c. 1.5 degrees d. 1.75 degrees 120. Type of feed mechanism where the primary radiating source is located just behind a small opening at the vertex of the paraboloid rather than at the focus. a. cassegrain feed b. center feed c. horn feed d. antenna feed 121. Discone radiation pattern is a. omnidirectional b. unidirectional c. figure-of-eight d. bidirectional 122. Which is properly terminated antenna? a. dipole b. marconi c. hertz d. rhombic 123. An example of a marconi antenna is _______. a. quarter wave vertical tower b. collinear c. yagi d. rhombic 124. At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? a. minimum voltage and maximum current b. minimum voltage and minimum current c. equal voltage and current d. maximum voltage and minimum current 125. Radiation resistance is the ratio of ______. a. radiated power to the antenna center current b. radiated power to the square of the antenna center current c. voltage to any point of the antenna d. square of voltage to the square of current at any point in the antenna
126. Consists of basic antenna connected to a transmission line plus one or more additional conductors a. parasitic array b. directors c. driven array d. reflectors 127. Which of the following is not a driven array? a. yagi b. broadside c. collinear d. end fire 128. What is used to determine phase difference between two broadcast antennas? a. a phase monitor b. a frequency monitor c. an amplitude monitor d. a power monitor 129. In antennas, which gives more forward gain? a. reflector b. driven element c. parasitic element d. director 130. Which of the following is longer? a. director b. reflector c. driven element d. parasitic element 131. Which is closer to the driven element? a. parasitic element b. driven element c. director d. reflector 132. How much do they differ in length from a half-wavelength? a. 5% b. 10% c. 15% d. 20% 133. How much more feed-point impedance does a folded dipole have than a normal dipole?
a. b. c. d.
two times as much three times as much four times as much five times as much
134. How is it possible to produce 70-ohm twin lead? a. by folding more parasitic element b. by manufacturing c. by increasing the radiation resistance d. by increasing the length of the antenna 135. With similar size parabolic, plane reflector, and corner-reflector beams, which has greater gain? a. plane reflector b. parabolic c. corner-reflector beam d. V-beam 136. With similar size, which has the narrowest lobes? a. parabolic b. V-beam c. corner-reflector beam d. plane reflector 137. Why would the wires of V-beam be closer together when used on higher frequencies? a. main lobe lays farther to wire b. main lobe lays closer to wire c. secondary lobes closer to wire d. secondary lobes farther to wire 138. How the V-beam is made unidirectional? a. impedance terminated b. capacitive terminated c. inductive terminated d. resistor terminated 139. Why might a rhombic be better than a V beam? a. it is resistor terminated b. more acreage needed c. less acreage needed d. it is unidirectional 140. Why is the usual rhombic not frequency – sensitive? a. unidirectional b. with its characteristic impedance
c. less acreage required d. main lobe is greater than back lobe 141. In what direction is the null of small diameter loop in relation to the plane of the loop? a. 45 degrees angle b. 180 degrees angle c. 360 degrees angle d. 90 degrees angle 142. When is a loop unidirectional? a. when horizontal b. when vertical c. when circular d. when unidirectional 143. Why are verticals sometimes top-loaded? a. to resonate on high frequency b. to decrease the electrical length c. to resonate on low frequency d. to look better 144. Why is pi-network superior to direct coupling to an antenna? a. reduce harmonic radiation b. better frequency response c. better radiation of energy d. reduce power dissipation 145. Why might L networks be used between an antenna and transmission line? a. step impedance up b. step impedance down c. better radiation of energy d. reduce power radiation 146. Why are antenna ammeters often shorted out or disconnected from the antenna except when readings are desired? a. to replace it with dummy b. not to interface with transmission c. for proper reception of signals d. to protect from lightning 147. Device to split transmission line current to two or more antenna towers a. splitter b. coupler c. isolator d. phasor circuit
148. What method can be used to determine the feed-point impedance of a vertical antenna? a. resistance substitution b. impedance matching c. dissipated resistance measurement d. grounding the antenna 149. In what unit is field intensity measured? a. volts b. amperes c. watts/m d. mV/m 150. How fast does low-frequency field strength attenuate? a. directly proportional to distance b. inversely proportional to distance c. directly proportional to time d. inversely proportional to time
MULTIPLE CHOICE QUESTIONS IN ELECTRONICS SYSTEMS AND TECHNOLOGIES (EST)
Broadcast Engineering MELVIN C. ARCEO, ECE PERC DC
ENCODED BY: BADILLO, AIMIE E. 2006105942 ECE003/C11
1. In stereophonic broadcast, the center frequency of each SCA Subcarrier shall be kept at all times within _______ Hz of the authorized frequency. a. 200 b. 300 c. 400 d. 500 2. Sawtooth generator circuits produce the scanning raster but the sync pulses are needed for a. linearity b. timing c. keystoning d. line pairing 3. Which of the following camera tubes has minimum lag? a. Vidicon b. Plumbicon c. Saticon d. Iconoscope 4. The service are in standard AM broadcast is described as ______ if there is no fading of signal. a. Class A b. Secondary c. Class B d. Primary 5. The vertical field-scanning frequency is ______ Hz. a. 30 b. 60 c. 525 d. 15,750 6. A 4.5-MHz signal which is equal to the difference between the picture and sound RF carrier frequencies in a 6-MHz TV channel. a. Audio frequency b. Video frequency c. Intercarrier frequency d. Subcarrier frequency 7. A system where the modulated RF picture and sound carrier signals are distributed in a cable network, instead of wireless system. a. CCTV b. MATV
c. CATV d. SATV
8. A class A FM station is limited in antenna height of ______ feet above average terrain. a. 1000 b. 2000 c. 4000 d. 5000 9. What circuit in the TV receiver is used to develop the high voltage needed to operate the picture tube? a. Low-voltage power supply b. Horizontal output c. Vertical sweep d. Sync separator 10. The modulated picture carrier wave includes the composite video signal as the a. Average carrier level b. Symmetric envelope of amplitude variations c. Lower sideband without the upper sideband d. Upper envelope without the lower envelope 11. With which emission type is the captureeffect more pronounced? a. CW b. FM c. SSB d. AM 12. The hue of color sync phase is a. red b. cyan c. blue d. yellow green 13. How much is the equivalent internal resistance of the electron beam with a 1.2mA beam current at 25 kV? a. 48 nano ohms b. 30 ohms c. 20.8 mega ohms d. 15.6 kilo ohms 14. The difference between the picture and sound carrier frequencies for channel 3 is ______ MHz.
a. b. c. d.
3.58 64.5 4.5 6.75
15. Refers to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. a. drift b. flashover c. frequency deviation d. deviation ratio 16. It is the measure of how many picture elements can be reproduced a. definition b. resolution c. detail d. any of these 17. A 3.58-MHz subcarrier signal for color in television a. Hue signal b. Video signal c. Audio signal d. Chroma signal 18. A class D FM station shall have an authorized power not exceeding ______ watts. a. 20 b. 15 c. 10 d. 5 19. Which of the following is not a benefit of cable TV? a. Lower-cost reception b. Greater stability c. Less noise, stronger signal d. Premium cable channels 20. The width of the vertical sync pulse in the Philippine TV system is a. 21H b. 3H c. H d. 0.5H 21. Term in communication which is referred, “to send out in all direction” a. announce
b. broadcast c. transmit d. media
22. The number of frames per second in the Philippine TV system is a. 60 b. 262 ½ c. 4.5 d. 30 23. It means multiple outlines of edges to the right in the picture. a. ghosting b. ringing c. fading d. snowing 24. In the Sawtooth waveform for linear scanning, a. the linear rise is for flyback b. the complete cycle includes trace and retrace c. the sharp reversal in amplitude produces trace d. the beam moves faster during trace and retrace 25. The purpose of pre-emphasis and deemphasis in FM broadcasting is to: a. increase the high frequency amplitude b. improve the audio harmonic c. decrease the low frequency amplitude d. improve the S/N ratio 26. The part of the visible spectrum where camera pickup tubes have the greatest output is a. red b. blue c. yellow-green d. infrared 27. The type of modulation of the sound carrier signal is ______. a. Pulse motion b. Phase modulation c. Amplitude modulation d. Frequency modulation
28. A video or audio signal that can be used directly to reproduce the picture and sound. a. Baseband signal b. Broadband signal c. Electromagnetic wave signal d. Modulated signal 29. Class B FM station should have an ERP not exceeding ______ kW. a. 50 b. 40 c. 30 d. 20 30. What technique is used to permit hundreds of TV signals to share a common cable? a. Frequency modulation b. Mixing c. Frequency division multiplexing d. Time division multiplexing 31. Another name for the horizontal retrace in a TV receiver is the a. ringing b. burst c. damper d. flyback 32. In the Philippine color television system, the intercarrier frequency, in MHz, is a. 3.58 b. 3.579645 c. 4.5 d. 45.75 33. In channel 14 (470 to 476 MHz), the 3.58MHz color signal is transmitted at a. 471.25 MHz b. 473.25 MHz c. 474.83 MHz d. 475.25 MHz 34. Interlaced scanning eliminates a. snowing b. flicker c. distortion d. fading 35. Beam alignment magnets for the camera tube are adjusted while rocking which color? a. Optical focus b. Electrical focus
c. Beam current d. Shading 36. What is a frequency discriminator? a. An FM generator b. A circuit for detecting FM c. A circuit for filtering two closely adjacent signals d. An automatic bandwidth circuit 37. A system used in television field operation to make on-the-spot video tape recordings using portable TV cameras and VTRs. a. SNG b. ENG c. HAFC d. MATV 38. Class B FM station shall have an authorized transmitter power not exceeding ______ kW. a. 10 b. 100 c. 1000 d. 10000 39. The total bandwidth of an NTSC TV signal is a. 3.58 MHz b. 4.5 MHz c. 6 MHz d. 10.7 MHz 40. Referred to the oscillator signal “leak through” from a property neutralized amplifier such as a master oscillator power amplifier. a. carrier b. stray signal c. back wave d. loss wave 41. Interlacing is used in television to a. produce the illusion of motion b. ensure that all lines on the screen are scanned, not merely the alternate ones c. simply the vertical sync pulse train d. avoid flicker 42. Coaxial cable for distribution system has an impedance of
a. b. c. d.
50 ohms 75 ohms 150 ohms 300 ohms
43. The average voltage value of the 3.58-MHz modulated chrominance signal is a. zero for most colors b. close to black for yellow c. the brightness of the color d. the saturation of the color 44. When does broadcast station conduct an equipment test? a. during day time b. during night time c. during experimental period d. at any time 45. It causes the picture information to spread out or crowded at one end of the rater compared to the opposite end. a. Linear scanning b. Interlaced scanning c. Non-linear scanning d. Retrace 46. If the camera cannot be placed far away enough to include everything in the scene, change the lens to one with a a. lower f rating b. higher f rating c. longer focal length d. shorter focal length
high powered RF transmission and are limited to radio frequency of about 500 kHz. a. Arc transmitter b. Hartley transmitter c. Spark transmitter d. Frequency transmitter 50. A technique where segments of videotape are joined by electronic erasing and recording to create a single program. a. masking b. segmenting c. editing d. programming 51. A class C FM station has an authorized power not exceeding ______watts of ERP. a. 500 b. 750 c. 1000 d. 2000 52. The assembly around the neck of a picture tube that produces the magnetic fields that deflect and scan the electron beams is called the _________. a. shadow mask b. phosphor c. electron gun d. yoke
47. Type of radio communication transmission utilizing frequency modulation technique a. television video b. broadcasting in 535-1606 kHz c. single sideband HF transmission d. television audio
53. An odd number of lines per frame form part of every one of the world’s TV systems. This is _____________________. a. done to assist interface b. purely an accident c. to ensure that line and frame frequencies can be obtained from the same original source d. done to minimize interference with the chroma subcarrier
48. The amount of color in the picture or color intensity in the ______. a. color level b. chroma level c. saturation d. any of these
54. The difference between the sound carrier and the color signal is a. 4.5 MHz b. 1.25 MHz c. 0.92 MHz d. 0.25 MHz
49. One of the early radio transmitters which produced keyed carrier generating purer waveform than spark transmitter, used for
55. In color television, it is made for uniform color in the raster. a. beam-landing adjustment
b. degaussing c. internal blanking adjustment d. background control 56. Which of the following camera tubes uses lead oxide for the photoconductive target plate? a. vidicon b. plumbicon c. saticon d. image orthicon 57. The number of fields is ______ per frame. a. 2 b. 60 c. 525 d. 262.5 58. An RF carrier wave that is frequency – modulated by the baseband audio signal in TV broadcasting. a. Audio signal b. Video signal c. Intercarrier signal d. Color signal 59. A class B FM station is limited in antenna height of ____ feet. a. 1000 b. 500 c. 250 d. 100 60. The HV anode supply for the picture tube of a TV receiver is generated in the a. mains transformer b. vertical output stage c. horizontal output stage d. horizontal deflection oscillator 61. A tap for the subscriber drop line has a a. high insertion loss b. high tap loss c. low tap loss d. 300-ohm impedance 62. Which system can be used for both recording and playback? a. CED b. VHD c. laser disk d. VHS
63. The hue 180 degrees out of phase with red is ______. a. cyan b. yellow c. green d. blue 64. It is used around the phosphor dots to make a darker black which improves contrast in the picture. a. black masking b. convergence adjustment c. shadow masking d. color parity adjustment 65. A lens with lower f rating is _____ lens that allows more light input. a. slower b. wider c. narrower d. faster 66. Picture frames are repeated at the rate of ___ per second. a. 30 b. 60 c. 45 d. 50 67. The effective radiated power of a class A FM station should not exceed ______ kW. a. 125 b. 30 c. 10 d. 1 68. In television, 4:3 represents the a. interface ratio b. maximum horizontal deflection c. aspect ratio d. ration of the two diagonals 69. Titling the viseo head gaps is necessary with the a. color under b. zero guard bands c. FM luminance signal d. Long – play tapes 70. It is a special camera tube with a test pattern printed in the image plate. a. vidicon
b. monoscope c. oscilloscope d. iconoscope
71. The number of lines scanned per frame in the raster on the picture tube screen is a. 525 b. 262 ½ c. 20 d. 10 72. 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 of operation and RF amplifier stage or stages that develop the high power output. The purpose of which is to develop a good frequency stability. a. MOPA b. Hartley c. Alexanderson d. Goldsmith 73. Camera signal output without sync is called ______. a. black burst b. generator lock video c. composite video d. non-composite video 74. The tint of the color is its _____. a. brightness b. contrast c. chroma d. hue 75. Which frequency band is the standard AM radio broadcast? a. HF b. UHF c. MF d. VHF 76. The I and Q composite color signals are multiplexed onto the picture carrier by modulating a 3.58 MHz subcarrier using a. FM b. PM c. DSB AM d. Vestigial sideband AM
77. The shadow mask in color picture tube is used to a. Reduce X-ray emission b. Ensure that each beam hits only its dots c. Increase screen brightness d. Provide degaussing for the screen 78. The video heads rotate at high velocity to increase the a. tape speed b. writing speed c. reel rotation d. tape tension 79. How do you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? a. use of a regulated power supply b. use of a new power supply c. use of high capacitor in the supply circuit d. loosen power supply shielding 80. The composite video signal includes the camera signal with the following except a. picture information b. sync pulses c. blanking pulses d. camera signal 81. A lens has an 8-cm focal length and 4-cm diameter. Its f rating is a. 2 b. 4 c. 8 d. 32 82. Which of the following is a possible cause for an abrupt frequency variation in a self – excited transmitter oscillator circuits resulting poor frequency stability to hold a constant frequency oscillation? a. DC and RF AC heating of resistor which cause a change in values b. Heating and expansion of oscillator coil c. Heating of capacitor in the oscillator d. Power supply voltage changes
83. How long does it take to scan 2 picture elements when 400 are scanned in 50 microseconds? a. 25 microsec b. 0.25 microsec c. 2.5 microsec d. 0.5 microsec
90. It is the light flux intercepted by a one-footsquare surface that is one-foot from a onecandlepower source. a. candela b. footcandle c. lux d. lumens
84. Anode voltage for the picture tube, developed from the output of the horizontal deflection circuit. a. Yoke voltage b. Flyback voltage c. Aquadag voltage d. Tube voltage
91. Refers to the possible cause of an abrupt frequency variations in a self-excited transmitter oscillator circuit resulting to a poor frequency stability to hold a constant oscillator. a. poor soldered connections b. heating of capacitor in the oscillator c. DC and AC heating of resistors which cause change in values d. Aging which cause change in condition in parts characteristics
85. The channel spacing in the Philippine FM broadcast standards a. 400 kHz b. 800 kHz c. 600 kHz d. 200 kHz 86. What is the black-and-white or monochrome brightness signal in TV called? a. RGB b. Color subcarrier c. Q an I d. Luminance Y 87. Which of the following is a midband cable TV channel? a. 6 b. 7 c. 14 d. 23 88. What is the primary purpose of an RF amplifier in a receiver? a. to vary the receiver image rejection by utilizing the AGC b. to provide most of the receiver gain c. to develop the AGC voltage d. to improve the receiver’s noise figure 89. The color with the most luminance is a. red b. yellow c. green d. blue
92. It is the difference in intensity between the black parts and white parts of the picture. a. brightness b. hue c. contrast d. illumination 93. The stereophonic subcarrier suppression level in the Philippines standards a. less than 4% modulation of the main carrier b. less than 3% modulation of the main carrier c. less than 2% modulation of the main carrier d. less than 1% modulation of the main carrier 94. The sound IF in a TV receiver is a. 4.5 MHz b. 10.7 MHz c. 41.25 MHz d. 45.75 MHz 95. The circuit the separates sync pulse from the composite video waveforms is a. the keyed AGC amplifier b. a clipper c. an integrator d. a differentiator
