AM-FM MCQS

1. ______ is the maximum sideband suppression value using filter system. A. 50 dB B. 60 dB C. 40 dB D. 30 dB

9. The process of impressing intelligence on the carrier is called A. modulation B. detection C. mixing D. impression

2. _______ determines components in FM. A. carrier frequency B. modulation frequency C. modulation index D. deviation ratio

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

the

number

of

sideband

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

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

C. 100 % D. 80 %

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

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

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

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

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

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

36. Which characteristic of a radio receiver refers to its ability to reject an unwanted signal? A. Sensitivity B. Selectivity C. Fidelity D. Quality

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

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 %

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 ANSWER 1. 50 dB 2. modulation index 3. H3E 4. baseband frequency 5. spectrum analyzer 6. converter 7. A3H 8. Vary in frequency with modulation 9. Modulation 10. spectrum analyzer 11. amplitude 12. LSB 13. Buffer 14. Center frequency 15. Deviation ratio 16. a frequency of 20 kHz and above 17. 1.47 18. 0.56 19. 12.5 20. No effect 21. Armstrong system 22. balanced modulator 23. Crystal radio receiver 24. image frequency 25. A3E 26. R3E 27. J3E 28. B8E 29. C3F 30. H3E 31. G3E 32. Better fidelity 33. Higher value of operating power 34. Less audio power required 35. Interface to other radio services 36. Selectivity 37. F3E 38. Modulation 39. Capture effect

40. 100 % 41. Frequency deviation 42. 112.5 kHz 43. Frequency modulation 44. Guard bands 45. All of the above 46. Modulation 47. Demodulation 48. Buffer amplifier 49. Depends on the type of modulation 50. 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

A. sq. root of 3 B. sq. root of 2 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

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

62. Envelope detection is concerned with the process of A. Mixing B. Heterodyning C. Modulation D. Rectification

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

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

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

65. A sine wave which is coherent with carrier has identical A. Amplitude B. Frequency C. Phase angle D. Both B and C

73. A reactance modulator is one method of obtaining A. Indirect FM B. Direct FM C. Demodulation D. Low frequency filtering

66. Frequency modulation and phase modulation are collectively referred to as A. Stereo B. Angle modulation C. High fidelity modulation D. FCC modulation

74. A device, now available in IC form, is useful for direct FM and as one element in the phse-locked loop. A. AFC B. AGC C. VCO D. LPF

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

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 ANSWER 51. Distortion and splatter 52. Increase 53. 50 % 54. Increase 55. 767 mA 56. sq. root of 2 57. 1002.5 kHz 58. 1199.3 kHz 59. Both A and C 60. 10 MHz 61. Both A and B 62. Rectification 63. Distortion 64. Heterodyning 65. Both B and C 66. Angle modulation 67. Amplitude 68. Frequency deviation 69. -5 kHz 70. 5 71. All of these 72. Varactor diode 73. Direct FM 74. VCO 75. Multiplication

76. Foster-Seeley discriminator 77. Both B and C 78. A triggered multivibrator 79. +10 % 80. Have the same frequency 81. The inputs are coherent 82. Voltage-controlled oscillator 83. Relative immunity to atmospheric noise (lightning) 84. LSB and USB 85. Increased by 50% 86. RF carrier 87. 100 88. Carrier 89. 66.66 % 90. J3E 91. 50 % 92. 3 components 93. Constant peak amplitude 94. Frequency modulation 95. One-half the original index 96. 666.6 W 97. A3E 98. Discriminator 99. Baseband 100. Angle

(1) The first symbol indicates the type of modulation on the transmitter carrier. A—Amplitude modulation, double sideband with identical information on each sideband. F—Frequency modulation. G—Phase modulation. J—Single sideband with suppressed carrier. P—Unmodulated pulse. W—Cases not covered above, in which an emission consists

of

the

main

carrier

modulated,

either

simultaneously or in a pre-established sequence, in a combination of two or more of the following modes: amplitude, angle, pulse. (2) The second symbol indicates the type of signal modulating the transmitter carrier. 0—No modulation. 1—Digital modulation, no subcarrier. 2—Digital modulation, modulated subcarrier. 3—Analog modulation.

(3) The third symbol indicates the type of transmitted

(i) For telemetry operations, when specifically authorized

information.

under this part, only A1D, A2D, F1D, or F2D emissions will

A—Telegraphy for aural reception.

be authorized.

B—Telegraphy for machine reception.

(j) For call box operations that may be authorized in

C—Facsimile.

accordance with § 90.241, only A1A, A1D, A2B, A2D, F1B,

D—Data, telemetry, and telecommand.

F1D, F2B, F2D, G1B, G1D, G2B, G2D, F3E or G3E

E—Voice.

emissions will be authorized.

N—No transmitted information.

(k) For radiolocation operations as may be authorized in

W—Combination of the above.

accordance with subpart F, unless otherwise provided for

(b) Authorizations to use A3E, F3E, or G3E emission also

any type of emission may be authorized upon a satisfactory

include the use of emissions for tone signals or signaling

showing of need.

devices whose sole functions are to establish and to

(l) For stations in the Public Safety and Industrial/Business

maintain communications, to provide automatic station

Pools utilizing digital voice modulation, in either the

identification, and for operations in the Public Safety Pool,

scrambled or unscrambled mode, F1E or G1E emission will

to activate emergency warning devices used solely for the

be authorized. Authorization to use digital voice emissions

purpose of advising the general public or emergency

is construed to include the use of F1D, F2D, G1D, or G2D

personnel of an impending emergency situation.

emission subject to the provisions of § 90.233.

(c) The use of F3E or G3E emission in these services will

(m) For narrowband operations in a 3.6 kHz maximum

be authorized only on frequencies above 25 MHz.

authorized bandwith, any modulation type may be used

(d) Except for Traveler's Information stations in the Public

which complies with the emission limitations of § 90.209.

Safety Pool authorized in accordance with § 90.242, only

(n) Other emissions. Requests for emissions other than

J3E emission will be authorized for telephony systems on

those listed in paragraphs (c) through (e) of this section will

frequencies below 25 MHz.

be considered on a case-by-case basis to ensure that the

(e) For non-voice paging operations, only A1A, A1D, A2B,

requested emission will not cause more interference than

A2D, F1B, F1D, F2B, F2D, G1B, G1D, G2B, or G2D

other currently permitted emissions.

emissions will be authorized. (f) For radioteleprinter operations that may be authorized in accordance with § 90.237, only F1B, F2B, G1B or G2B emissions will be authorize above 25 MHz, and A1B or A2B emissions below 25 MHz. (g) For radiofacsimile operations that may be authorized in accordance with § 90.237, only F3C or G3C emissions will be authorized above 25 MHz, and A3C emissions below 25 MHz. (h) [Reserved]

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 flipflops 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 super heterodyne 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 super heterodyne 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 selfgenerated 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 super heterodyne 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 amplitudemodulated (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 amplitudecompandored 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 superheterodyne 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-toaverage power during a modulation peak in a singlesideband 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 101. Bandwidth 102. H3E 103. Continuous modulation 104. Pulse modulation 105. Coefficient of modulation 106. Carrier shift 107. The oscillator is crystal-controlled 108. Frequency translation 109. Balanced modulator 110. Both B and C 111. 30.8 MHz 112. 0.6 radian 113. Nonlinear 114. Push-push 115. Frequency synthesizer 116. 4 117. Balanced modulator 118. Indirect 119. All of these 120. The change of the crystal oscillator frequency by loading 121. Indirect FM 122. 123. Both A and B 124. TRF 125. Weak antenna signals 126. Bandwidth variations over the tuning range 127. Modulator 128. R–F amplifier 129. Mixer 130. Frequency translation 131. Internal noise 132. Reduction of receiver internal noise 133. Smaller 134. Noise figure 135. 120.1 MHz 136. 88.5 MHz 137. The image rejection ratio 138. Powdered iron 139. Skirt steepness 140. AGC 141. Squelch 142. Noise blanker 143. SBB voice 144. The audio voice information 145. An increase of the oscillator frequency 146. The noise floor of the receiver 147. Open circuit in the AGC’s filter capacitor 148. Cross-modulation interference 149. Limits the amplitude of the IF signal to the required level 150. Connecting a capacitor between the B+ and lead ground 151. Crossmodulation 152. Stray coupling is minimized 153. 4 154. Prevent the generation of spurious oscillations 155. Blocking dynamic range 156. RF amplifier, mixer, IF amplifier, AF amplifier 157. Filter ringing

158. IF amplifier 159. Better signal-to-noise-ratio 160. Low-level modulation 161. Ensuring good RF shielding between the transmitter 162. 3,000 Hz 163. A3C 164. In the receiver front end 165. Installing a filter at the receiver 166. F3E 167. The presence of a strong signal on a nearby frequency 168. Amplitude of the modulating tone and frequency of the carrier 169. Better rejection ratio 170. Bandwidth and noise figure 171. Undesired signals will reach the audio stage 172. FM receiver 173. Prevents any amplitude modulation of the IF signal 174. Loose 175. Multiplied by four 176. 2.4 kHz 177. Resistor 178. Avoid the requirement of neutralizing the stage 179. Rectifies and filters 180. All of these 181. Insulating enclosures around the receiver 182. Television 183. Approximately 1000 W 184. Limiter stage 185. Single sideband, suppressed carrier 186. Approximately 2.5 to 1 187. Higher 188. Improvement in frequency stability of the oscillator 189. A3F 190. A network consisting of one inductor and two capacitors 191. With a reactance modulator on the oscillator 192. Installing resistive spark plugs 193. Transmitter’s output signal when the modulation is zero 194. Final IF amplifier, which also acts as a limiter stage 195. Discriminator 196. The loudest signal received is the only demodulated signal 197. Modulating the plate voltage of a class-C amplifier 198. High modulating frequencies 199. The modulation of an unwanted signal is heard on the desired signal 200. FM 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 distortion 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 signals? 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. 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. Envelope detector B. Balanced modulator C. Mixer D. 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. Transponder B. Product detector C. Converter D. 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 251. A method that applied the modulated wave to the vertical deflection circuit of the oscilloscope and the modulating signal to the horizontal deflection circuit. a. Trapezoidal method b. Circular method c. Square method d. Any method 252. The heart of all methods of single-sideband modulation and demodulation a. Modulator b. Balanced modulator c. Modulation d. demodulation 253. If the frequency and phase are parameters of carrier angle, which is a function of time, the general term ___________-cover both. a. Amplitude modulation b. Frequency modulation c. Phase modulation d. Angle modulation 254. In FM radio communication system, narrow-band (NBFM) is used rather than wideband (WBFM), because it, a. Improves signal to noise ration b. Reduces interchannel interference c. Provides maximum coverage for a given amount of power d. All of the above 255. Radio transmitter basically consists of two principal parts, one reproducing a carrier frequency and one for __________. a. IF Frequency b. RF Frequency c. Modulating Frequency d. Power 256. Is a measure of its ability to maintain as nearly a fixed frequency as possible over as long as time interval as

possible. a. Receiver Noise Factor b. Selectivity c. Sensitivity d. Frequency stability 257. Is the effect of two-transmitter when they are in close proximity. This results into the sum and difference frequencies of two carriers. a. Intermodulation effect b. Intermodulation interference c. Intermodulation product d. intermodulation 258. _________ is a continuous frequency capable of being modulated or impressed with a second information carrying signal. a. Carrier frequency b. Center frequency c. IF frequency d. RF frequency 259. The varactor diode used in FM may be represented by the approximate equivalent circuit of the _____ in series with a ________. a. Diode, capacitor b. Diode, resistor c. Capacitor, resistor d. Any of these 260. The name varactor comes from variable _________. a. Resistor b. Capacitor c. Diode d. reactor 261. 75 microseconds pre-emphasis time is used in __________. a. FM b. AM c. TV d. None of these 262. Recovers the modulating voltage from the frequency modulation by utilizing the phase angle shift between primary and secondary voltages of tuned oscillators. a. Direct method b. Indirect method c. Foster-Seeley discriminator d. Slope detector 263. Is used in FM receivers to “lock onto” the received signal and stabilized receptions. a. Automatic Gain Control b. Automatic Frequency Control c. Muscle Control d. Automatic Frequency Gain Control 264. Are amplifier circuits that are used to eliminate amplitude modulation and amplitude-modulated noise from received FM Signals before detection.

a. Demodulators b. Diode detector c. Amplitude limiters d. None of these 265. If the total sideband power is 12.5% of the total radiated power, find the modulation index. a. 50 percent b. 53.4 percent c. 26.2 percent d. 32.3 percent 266. Carriers are spaced at 20 kHz, beginning at 100 kHz. Each carrier is modulated by a signal with a 5 kHz bandwidth. Is there interference from the sideband? a. Yes b. No c. Maybe d. Secret 267. For an unmodulated carrier of 150 V and a modulated peak value of 230 V. What is the modulation index a. 0.35 b. 0.533 c. 0.652 d. 0.42 268. New frequencies outside the regular AM spectrum are called ___________. a. Distortion b. Interference c. Splatter d. Harmonic 269. A DSB-SC has a total power of 350 watts with 100% modulation suppresses 50% of the carrier, and the suppressed carrier power goes to the sidebands. How much power is in the sidebands? a. 116.67 W b. 233.33 W c. 175 W d. 350 W 270. A DSB-SC system must suppress the carrier by 30 dB from its original value of 30 W. What value must the carrier be reduced? a. 30000 W b. 0.03 W c. 300 W d. 0.003 W 271. ___________, which further amplifies the signal and has the bandwidth and passband shaping appropriate for the received signal. a. RF stage b. Mixer and local oscillator stage c. IF stage d. AF stage 272. In FM, a bandwidth estimate 98 percent level of Bessel functions

a. Approximate bandwidth b. Narrow-band Bandwidth c. Carson’s rule d. Wideband bandwidth 273. The complete series of stages for reproducing the FM signal with the desired carrier and deviation is the _______. a. Modulator b. Exciter c. IF stage d. RF stage 274. Is the ability of FM system to provide low-noise, high fidelity music background/broadcast.. a. Monophonic b. Stereophonic c. Stereonic d. SCA 275. It make use of the shape of IF filter frequency response roll-off versus frequency. a. Foster Seeley b. Slope detector c. Diode detector d. Quadrature detector 276. In AM, modulation index is a number lying between ____ and 1. a. 2 b. 5 c. 0 d. 3 277. This form of modulation is also known as independent sideband emission. a. A3E b. R3E c. H3E d. B8E 278. An attenuated carrier is reinserted into the SSB signal to facilitate receiver tuning and demodulation. a. A3E b. R3E c. H3E d. B8E 279. Standard AM used for broadcasting a. A3E b. R3E c. H3E d. B8E 280. Single sideband, suppressed carrier in which the carrier is suppressed by at least 45 dB in the transmitter. a. A3E b. R3E c. H3E d. B8E 281. The shift in the carrier frequency from the resting point compared to the amplitude of the modulating signal is

called _______. a. Index b. Deviation ratio c. Carrier frequency d. Deviation frequency 282. In FM, the amplitude of the modulated frequency wave remains ___________ at all times. a. Varying b. Dependent c. Constant d. variable 283. An AM has a maximum span of 30 V, what is the required minimum span to attain 100% modulation? a. 30 V b. 20 V c. 0 V d. None of these 284. DZMM having a carrier frequency of 630 kHz is modulated by 2.6 kHz audio signal having an amplitude of 37.5 V. What is the amplitude voltage of 630 kHz carrier frequency at 0.35 modulation index? a. 57.6 V b. 107.14 V c. 206.5 V d. 86.2 V 285. If the sideband power is 50% of the carrier power, what is the modulation index? a. 50% b. 75% c. 90% d. 100% 286. If the increase power is 180 watts at 1 kW unmodulated output power the modulation index is _________. a. 75% b. 60% c. 50% d. 25% 287. In AM, if the unmodulated power carrier is 10 kW, and the total power is 15 kW, what is the upper sideband power at 100% modulation index? a. 25 kW b. 2 kW c. 2.5 kW d. 4 kW 288. If the input resistance of the base station of AM broadcast produced 20 kW carrier power, at what modulation index should the antenna rise at 108.63 A? a. 20% b. 50% c. 60% d. 80% 289. ________ used a phase detector to compare the

phase and frequency of the received signal to the VCO output. a. PIL b. PAL c. PLL d. PLI 290. A filter with a roll-off of 6 dB/kHz is used as a slope detector. The input signal varies with +3 kHz deviation from center carrier frequency. How many dB down is the output at full deviation? a. 9 dB b. -18 dB c. 18 dB d. -9 dB 291. A receiver limiter requires a 20 mV signal for quieting operation. The voltage gain between the RF input and the limiter is 57.7 dB, what is the input at the antenna terminal assuming equal resistance? a. 75.6 mV b. 26.67 uV c. 52.3 uV d. 49.6 uV 292. A 1-MHz carrier is modulated with a resulting 100 Hz deviation. It undergoes x36 multiplication, followed by mixing with a 34.5 MHz signal and re-multiplication by 72. What is the final carrier and deviations? a. 5076 MHz, ± 2592 MHz b. 2592 MHz, ± 259.2 kHz c. 2592MHz, ± 5076 MHz d. 259.2 MHz, ± 108 kHz 293. For standard commercial broadcast FM, the deviation ratio is ________. a. 15 b. 75 c. 5 d. 10 294. A system has 150 kHz of bandwidth available for 10 kHz modulation signal. What is the approximate deviation to be used? a. 35 kHz b. 65 kHz c. 25 kHz d. 15 kHz 295. An FM has a deviation of 100 kHz and a modulating frequency of 15 kHz, what happen to m if the deviation triples? a. 6.66 b. 2.22 c. 4.12 d. 0.20 296. A receiver for a signal at 100 MHz uses a 10.7 MHz IF and low tracking. What is the image frequency? a. 89.3 MHz

b. 78.6 MHz c. 52.5 MHz d. 35.2 MHz 297. What is the change in resonant frequency of the actual varactor capacitance value differs by -5% (0.05) of the nominal value? a. 2.06 b. 3.02 c. 1.03 d. 5.06 298. An oscillator resonate at 1 MHz with a nominal 100 pF capacitor and 0.25 mH inductor, what s the resonant frequency of the actual capacitor value is +20% of the nominal value? a. 1.006 MHz b. 0.9188 MHz c. 3.625 MHz d. 2.00123 MHz 299. “Front end” is also called _________. a. IF stage b. AF stage c. RF stage d. None of these 300. Undesired signal on the other side of the local oscillator output will have the same difference frequency and pass into the IF amplifier. a. Carrier frequency b. Sum frequency c. Difference frequency d. Image frequency 201. Television 202. F3C 203. Intermodulation interference 204. Desensitizing 205. Bandwidth of emission and occupied bandwidth 206. A normal condition 207. Amplitude of the modulating signal 208. Maximum frequency swing to the highest modulating frequency 209. An output, whose frequency differs from the IF by 1 kHz 210. Projected cut-off 211. Amplify of an AM signal 212. Cross-modulation interference 213. Peak negative voltage 214. FM and double sideband AM 215. Percentage of modulation 216. Capture effect 217. Double-sideband AM 218. Zero-modulation 219. 270 kHz 220. Linear mixing 221. The tuned circuit 222. Having the carrier vary a resistance 223. Variable resistance 224. PIN diode 225. 96 V

226. Demodulator 227. Envelope detector 228. Balanced modulator 229. Lattice modulator 230. Switches 231. DSB 232. Differential amplifier 233. Crystals 234. Phase shifting 235. Product detector 236. Mixer 237. Linear summing 238. Lower complexity and cost 239. Excessive use of spectrum space 240. High-frequency spikes 241. Limiter 242. Class C 243. Single sideband with suppressed carrier 244. Filter 245. DSB 246. Single sideband, suppressed carrier 247. Demodulation 248. BFO 249. Diode detector 250. Lattice modulator 251. Trapezoidal method 252. Balanced modulator 253. Angle modulation 254. All of the above 255. Modulating Frequency 256. Frequency stability 257. Intermodulation interference 258. Carrier frequency 259. Capacitor, resistor 260. reactor 261. FM 262. Foster-Seeley discriminator 263. Automatic Frequency Control 264. Amplitude limiters 265. 53.4 percent 266. No 267. 0.533 268. Splatter 269. 233.33 W 270. 0.03 W 271. IF stage 272. Carson’s rule 273. Exciter 274. Stereophonic 275. Slope detector 276. 0 277. B8E 278. R3E 279. A3E 280. H3E 281. Deviation ratio 282. Constant 283. 0 V 284. 107.14 V 285. 100%

286. 60% 287. 2.5 kW 288. 60% 289. PLL 290. 18 dB 291. 26.67 uV 292. 2592 MHz, ± 259.2 kHz 293. 5 294. 65 kHz 295. 0.20 296. 78.6 MHz 297. 1.03 298. 0.9188 MHz 299. RF stage 300. Image frequency

301. One of the following refers to an output of a balanced modulator a. SSB b. ISB c. AM d. DSB 302. Which of the following components is used to produce AM at very high frequencies? a. Cavity resonator b. PIN diode c. Varactor d. Thermistor 303. A third symbol emission which represent data transmission including telemetry, and telecommand a. B b. D c. C d. N 304. In an AM wave, useful power is carried by a. None of these b. Sidebands c. Both the sidebands and the carrier d. Carrier 305. Determine the modulation index of an standard FM broadcast having a hypothetical maximum carrier frequency deviation of ±12 kHz and a maximum modulating frequency pf 4kHz. a. 9 b. 6 c. 3 d. 4 306. The process by which the intelligence signals normally at lower frequency are removed from the transmission frequency after it is received in the receiver station. a. Detection b. Demodulation c. Amplification d. Modulation 307. What is meant by the term modulation?

a. The squelching of a signal until a critical signal-to-noise ratio is reached b. Carrier rejection through phase nulling c. A linear amplification mode d. A mixing process whereby information is imposed upon a carrier 308. What is a balanced modulator? a. An FM modulator that produces balance deviation b. A modulator that produces a DSBSC signal c. A modulator that produces a SSBSC signal d. A modulator that produces a full carrier signal 309. What is a reactance modulator? a. A circuit that acts as a variable resistance or capacitance to produce FM signals b. A circuit that acts as a variable resistance or capacitance to produce AM signals c. A circuit that acts as a variable inductance or capacitance to produce FM signals d. A circuit that acts as a variable inductance or capacitance to produce AM signals 310. How can an SSB phone signal be generated? a. By dividing product detector with a DSB signal b. By using a reactance modulator followed by a mixer c. By using a loop modulator followed by a mixer d. By using a balanced modulator followed by a filter 311. How can a DSB phone signal be generated? a. By feeding a phase modulated signal into a low pass filter b. By using a balanced modulator followed by a filter c. By detuning a Hartley oscillator d. By modulating the plate voltage of a class C amplifier 312. First symbol in the designation of radio signals emission which refers to use of an unmodulated carrier. a. J b. N c. H d. A 313. One of the following is a communications filter generally used in the transceiver of a single sideband generator. a. Lowpass filter b. Crystal filter c. Bandpass filter d. Mechanical filter 314. What is the modulation index for an AM signal having Vmax and Vmin of 2.6 and 0.29, respectively? a. 0.799 b. 0.111 c. 0.894 d. 0.639 315. What is the bandwidth of an AM signal modulated by a 15-kHz intelligence signal?

a. 7.5 kHz b. 15 kHz c. 30 kHz d. 60 kHz 316. If a transmitter supplies 10 kW to the antenna when it is unmodulated, determine the total radiated power when it is modulated at 30% a. 10.45 watts b. 10750 watts c. 11.5 kilowatts d. 10450 watts 317. Which of the following waveform characteristics determines the wavelength of a sine wave? a. Phase b. Amplitude c. Period d. Phase angle 318. In the F3E signal, what is the term for the ratio between the deviation of a frequency modulated signal and the modulating frequency? a. FM compressibility b. Quieting index c. Modulation index d. Percentage of modulation 319. Which frequency band is the standard AM radio broadcast? a. HF b. UHF c. MF d. VHF 320. The letter-designation B8E is a form of modulation also known as a. Pilot carrier system b. Independent sideband emission c. Lincompex d. Vestigial sideband transmission 321. What are the two general categories of methods for generating emission F3E? a. The only way to produce an emission F3E signal is with reactance modulator on the oscillator b. The only way to produce an emission F3E signal is with a balanced modulator on the oscillator c. The only way to produce an emission F3E signal is with a balanced modulator on the audio amplifier d. The only way to produce an emission F3E signal is with a reactance modulator on the final amplifier 322. 100% modulation in AM means a corresponding increase in total power by ____. a. 25% b. 75% c. 100% d. 50% 323. How does the SSB transmitter output power normally

expressed? a. Average power b. In terms of peak envelope power c. In terms of peak-to-peak power d. Peak power 324. Determine from the following the common use of DSB in broadcast and telecommunications a. Satellite communication b. FM/TV stereo c. Two-way communications d. Telephone systems 325. What is the source of sidebands in frequency modulation? a. Oscillator b. Baseband frequency c. Mixer d. Carrier harmonics 326. What is the source of sidebands in frequency modulated voice? a. A3F b. A3J c. F3E d. J3E 327. The third symbol in the designation of radio emission under the ITU refers to a. Type of modulation of the main carrier b. Nature of signals c. Type of information to be transmitted d. Nature of multiplexing 328. An AM transmission of 3 kW is 100% modulated. If it is transmitted as an SSB signal, what would be the total power transmitted? a. 500 W b. 1000 W c. 1500 W d. 2000 W 329. This circuit has the function of demodulating the frequency-modulated signal. It is a a. Automatic gain control b. Automatic frequency control c. Envelope detector d. Foster-Seeley discriminator 330. Calculate the power in one sideband of an AM signal whose carrier power is 50 watts. The unmodulated current is 2 A while the modulated current is 2.4 A. a. 22 W b. 33 W c. 11 W d. 44 W 331. The method of generating FM used by broadcasting station is a. Direct b. All of these

c. Indirect d. Insertion 332. 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 333. An AM transmitter is modulated by two sine waves at 1.5 kHz and 2.5 kHz with modulations of 20 percent and 80 percent respectively. Calculate the effective modulation index. a. 0.7776 b. 0.6 c. 0.8246 d. 1.0 334. A DSBSC system must suppress the carrier by 50 dB for its original value of 10 W. To what value must the carrier be reduced? a. 1 milliwatt b. 10 microwatts c. 0.10 milliwatts d. 0.01 microwatts 335. Which circuit in the AM transmitter does the frequency translation? a. Synthesizer b. Modulator c. Mixer d. Booster 336. A phase modulator has Kp= 2 rad/V. What RMS voltage of a sine wave would cause a peak phase deviation of 30 degrees? a. 0.158 V b. 0.185 V c. 0.518 V d. 0.815 V 337. In a phase-locked loop, VCO stands for a. Variable capacitor oscillator b. Varactor-capacitor oscillator c. Voltage-controlled oscillator d. VHF control oscillator 338. Diagonal clipping in envelope detection will result in a. Distortion b. Diagonal clipping c. Phase reversal d. Amplitude damage 339. An AM transmitter supplies a 10 kW of carrier power to a 50 ohm load. It operates at a carrier frequency of 1.2 MHz and is 85% modulated by a 3 MHz sine wave. Calculate the RMS voltage of the signal. a. 825 W b. 262. 61 V c. 1166.7 V

d. 825 V 340. What will be the total sideband power of the AM transmitting station whose carrier power is 1200W and a modulation of 95%? a. 270.75 W b. 900 watts c. 1.8 kW d. 542 W 341. Which among the following is capable of generating frequency conversion? a. Balanced modulator b. Low-Q LC Circuit c. Transmitter d. Circulator 342. The most commonly used AM demodulator a. Envelope detector b. PLL c. Mixer d. Balanced modulator 343. Which is a disadvantage of direct FM generation? a. The need for an AFC circuit b. The need for an AGC circuit c. Two balanced modulators are used d. The use of Class A amplifier which is very inefficient 344. Frequency division is useful in the implementation of a/an a. AM demodulator b. Frequency synthesizer c. AGC circuit d. FM demodulator 345. A particular synthesizer which contains only a single crystal is a. Direct b. Crystal-modulated c. Indirect d. Exact 346. Type of emission most affected by selective fading a. FM and DSB AM b. SSB and TV c. CCTV and CW d. CW and SSB 347. Which major element will not be found in every superheterodyne receiver? a. RF amplifier b. IF amplifier c. LO d. Mixer 348. A system uses a deviation of 100 kHz and a modulating frequency of 15 kHz. What is the approximate bandwidth? a. 115 kHz b. 230 kHz c. 170 kHz

d. 340 kHz 349. A quadrature detector requires that a. The inputs are coherent b. Four gates are provided c. The inputs are in phase d. The inputs are similar 350. What is the power in one sideband of an AM signal whose carrier power is 300 W, with 80 percent modulation? a. 396 W b. Zero c. 48 W d. 96 W 351. Determine the resonant frequency of a series combination of a 0.001 microfarad capacitor and a 2 – milihenry inductor. a. 112.5 kHz b. 35.59 kHz c. 1125.4 MHz d. 3.26 MHz 352. Which of the following is not a typical part of every radio transmitter? a. Carrier oscillator b. Driver amplifier c. Mixer d. Final power amplifier 353. What is the approximate magnitude of the impedance of a parallel RLC circuit at resonance? a. Approximately equal to the circuit resistance b. Approximately equal to XL c. Low, as compared to the circuit resistance d. Approximately equal to XC 354. What are the three major oscillator circuits often used in radio equipment? a. Taft, Pierce, and negative feedback b. Colpitts, Hartley, and Taft c. Taft, Hartley, and Pierce d. Colpitts, Hartley, and Pierce 355. How is a positive feedback coupled to the input in a Hartley oscillator? a. Through a neutralizing capacitor b. Through a capacitive divider c. Through a link coupling d. Through a tapped coil 356. How is the positive feedback coupled to the input in a Colpitts oscillator? a. Through a tapped coil b. Trough link coupling c. Through a capacitive divider d. Through a neutralizing capacitor 357. How is a positive feedback coupled to the input in a Pierce oscillator? a. Through a tapped coil b. Trough link coupling

c. Through a capacitive divider d. Through a neutralizing capacitor 358. Which of the three major oscillator circuits used in radio equipment utilizes a quartz crystal? a. Negative feedback b. Hartley c. Colpitts d. Pierce 359. What is the piezoelectric effect? a. Mechanical vibration of a crystal by the application of a voltage b. Mechanical deformation of a crystal by the application of a magnetic field c. The generation of electrical energy by the application of light d. Reversed conduction states when pn-junction is exposed to light 360. What is the major advantage of a Pierce oscillator? a. It is easy to neutralize b. It doesn’t require an LC tank circuit c. It can be tuned over a wide range d. It has high output power 361. Which type of oscillator circuit is commonly used in a VFO? a. Pierce b. Colpitts c. Hartley d. Negative feedback 362. Why is the Colpitts oscillator circuit commonly used in a VFO? a. The frequency is a linear function of the load impedance b. It can be used with or without crystal lock-in c. It is stable d. It has high output power 363. How is the efficiency of a power amplifier determined? a. Efficiency = (RF power out / dc power in) x 100% b. Efficiency = (RF power in / RF power out) x 100% c. Efficiency = (RF power in / dc power in) x 100% d. Efficiency = (dc power in / RF power in) x 100% 364. For reasonably efficient operation of a transistor amplifier, what should be the load resistance be with 12 volts at the collector and a 5 watts power output? a. 100.3 ohms b. 14.4 ohms c. 10.3 ohms d. 144 ohms 365. What order of Q is required by a tank circuit sufficient to reduce harmonics to an acceptable level? a. Approximately 120 b. Approximately 12 c. Approximately 1200 d. Approximately 1.2 366. What is the flywheel effect?

a. The continued motion of a radio wave through space when the transmitter is turned off b. The back and forth oscillation of electrons in an LC circuit c. The use of a capacitor in a power supply to filter rectified AC d. The transmission of a radio signal to a distant station by several hops through the ionosphere 367. How can parasitic oscillations be eliminated from a power amplifier? a. By tuning for maximum SWR b. By tuning for maximum power output c. By neutralization d. By tuning the output 368. If the spectrum is shifted in frequency with no other changes, this is known as a. Frequency multiplication b. Sideband movement c. Baseband orientation d. Frequency translation 369. 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 370. If the frequency of each component in a signal spectrum is increased by the same fixed amount, this is known as a. Up conversion b. Demodulation c. Frequency translation d. Both a and c 371. 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 372. Any device to be used as a frequency multiplier must be a. Active b. Passive c. Linear d. Nonlinear 373. A particular amplifier circuit used for frequency coupling is known as a. Push-push b. Push-pull c. Pull-push d. Pull-pull 374. Frequency division is useful in the implementation of a a. AM demodulation

b. Frequency synthesizer c. FM demodulator d. AGC circuit 375. Indirect frequency synthesizers will include a. phase-locked loop b. voltage-controlled oscillators c. multiple bank crystals d. both A and B 376. A particular frequency synthesizer contains only a single crystal. What words describe this synthesizer? a. Crystal modulated b. Inexact c. Indirect d. Deficient 377. A recognizable feature of a CW transmitter is a. Keyed transmitter b. Power amplification c. Frequency generation d. All of the above 378. 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 379. An AM broadcast transmitter in the multi-kilowatt operating range will have what form of final amplifier? a. Solid-state devices b. Vacuum tubes c. Travelling wave tubes d. Both a and b 380. In a broadcast station, the AGC is referred to as a. Automatic gain control limiter b. Compression amplifier c. Loudness controller d. All of the above 381. Class C amplifiers are not used in which type of transmitter? a. AM b. SSB c. CW d. FM 382. A circuit that isolates the carrier oscillator from load changes is called a a. Final amplifier b. Driver amplifier c. Linear amplifier d. Buffer amplifier 383. Bias for class c amplifier produced by an input RC network is known as a. Signal bias b. Self-bias

c. Fixed external bias d. Threshold bias 384. Collector current in a class C amplifier is a. Sine wave b. Half-sine wave c. Pulse d. Square wave 385. Neutralizing is the process of a. Cancelling the effect of internal device capacitance b. Bypassing undesired alternating current c. Reducing gain d. Eliminating harmonics 386. In an AM transmitter, a clipper circuit eliminates a. Harmonics b. Splatter c. Over-deviation d. Excessive gain 387. The final power amplifier in an FM transmitter usually operates class a. A b. B c. C d. D 388. A transistor RF power amplifier can be tuned for a. Minimum IC in the next stage b. Zero signal in the next stage c. Minimum IC in the same stage d. Maximum IC in the same stage 389. The purpose of a balanced modulator circuit is to eliminate the a. Carrier b. Upper sideband c. Lower sideband d. Baseband signal 390. A frequency multiplier circuit a. Operates class A b. Is tuned to a harmonic of the input signal c. Needs parasitic oscillations d. Is usually pulse modulated 391. An IF transformer of a radio receiver operates at 456 kHz. The primary circuit has a Q of 50 and the secondary has a Q of 40. Find the bandwidth using the optimum coupling factor. a. 10.192 kHz b. 15.288 kHz c. 152.88 kHz d. 101.92 kHz 392. A varactor has a maximum capacitance of 80pF and is used in a tuned circuit with a 100 microhenry inductor. Find the tuning voltage necessary for the circuit to resonate at twice its resonant frequency with no tuning voltage applied. a. 5 V b. 2.5 V

c. 7.5 V d. 4.25 V 393. A phase-locked loop has a VCO with a free-running frequency of 14 MHz. As the frequency of the reference input is gradually raised from zero, the loop locks at 12 MHz and comes out of lock again at 18 MHz. Calculate the capture range. a. 4 MHz b. 2 MHz c. 12 MHz d. 8 MHz 394. If the frequency fed to the pre-amplifier of a basic transmitter with multipliers is composed of a pair of triplers and a doubler is 198 MHz, what frequency should the oscillator operate? a. 11 MHz b. 33 MHz c. 22 MHz d. 66 MHz 395. A phase-locked loop has a VCO with a free running frequency of 14 MHz. As the frequency of the reference input is gradually raised from zero, the loop locks at 12 MHZ and comes out of lock again at 18 MHz. Calculate the lock range. a. 4 MHz b. 2 MHz c. 12 MHz d. 8 MHz 396. A crystal oscillator is accurate within 0.0005%. How far off frequency could its output be at 37 MHz? a. 135 Hz b. 150 Hz c. 185 Hz d. 224 Hz 397. A transmitter has a carrier power output of 10 W at an efficiency of 80%. How much power must be supplied by the modulating amplifier for 100% modulation? a. 6.25 W b. 7.14 W c. 12.5 W d. 14.3 W 398. A transmitter operates from a 16 V supply, with a collector current of 2 A. The modulation transformer has a turns ratio of 4:1. What is the load impedance seen by the audio amplifier? a. 96 ohms b. 128 ohms c. 6 ohms d. 8 ohms 399. A collector-modulated class C amplifier has a carrier output power of 150 W and an efficiency of 80%. Calculate the transistor power dissipation with 100% modulation. a. 93. 75 W

b. 120 W c. 64 W d. 56. 25 W 400. An AM transmitter is required to produce 20 W of carrier power when operating from a 25 V supply. What is the required load impedance as seen from the collector? a. 15.625 ohms b. 22.5 ohms c. 11.25 ohms d. 31.25 ohms 401. What is receiver desensitizing? a. A burst of noise when the squelch is set to low b. A burst of noise when the squelch is set to high c. A reduction in receiver sensitivity because of a strong signal on a nearby frequency d. A reduction in receiver sensitivity is turned down 402. What is the term used to refer to the reduction of receiver gain caused by the signals of a nearby station transmitting in the same frequency band? a. Desensitizing b. Quieting c. Cross-modulation interference d. Squelch gain roll back 403. What is the term used to refer to a reduction in receiver sensitivity caused by unwanted highlevel adjacent channel signals? a. Intermodulation distortion b. Quieting c. Desensitizing d. Overloading 404. How can receiver desensitizing be reduced? a. Ensure good RF shielding between the transmitter and receiver b. Increase the transmitter audio gain c. Decrease the receiver squelch gain d. Increase the receiver bandwidth 405. What is cross-modulation interference? a. Interference between two transmitters of different modulation types b. Interference caused by audio rectification in the receiver preamp c. Decrease the receiver squelch gain d. Modulation from an unwanted signal is heard in addition to the desired signal 406. What is the term used to refer to the condition where the signals from a very strong station are super imposed on the other signals being received? a. Intermodulation distortion b. Cross-modulation interference c. Receiver quieting d. Capture effect 407. How can cross-modulation in a receiver be reduced? a. By installing a filter at the receiver

b. By using a better antenna c. By increasing the receiver’s RF gain while decreasing the AF gain d. By adjusting the passband tuning 408. What is the result of cross-modulation? a. Decrease in modulation level of transmitted signals b. Receiver quieting c. The modulation of an unwanted signal is heard on the desired signal d. Inverted sidebands in the final stage of the amplifier 409. What is the capture effect? a. All signals on a frequency are demodulated by an FM receiver b. All signals on a frequency are demodulated by an AM receiver c. The loudest signal received is the only demodulated signal d. The weakest signal received is the only demodulated signal 410. What is a product detector? a. A detector that provides local oscillator for input to the mixer b. A detector that amplifies and narrows the bandpass frequencies c. A detector that uses mixing process with a locally generated carrier d. A detector used to detect cross-modulation products 411. What is the term used to refer to the reception blockage of one FM-phone signal? a. Desensitization b. Cross-modulation interference c. Capture effect d. Frequency discrimination 412. What is the process of detection? a. The process of masking out the intelligence on a received carrier to make an S-meter operational b. The recovery of intelligence from the modulated RF signal c. The modulation of a carrier d. The mixing of noise with the received signal 413. What is the principle of detection in a diode detector? a. Rectification and filtering of RF b. Breakdown of the Zener voltage c. Mixing with the noise in the transition region of the diode d. The change of reactance in the diode with respect to frequency 414. How are FM phone signals detected? a. By a balanced modulator b. By a frequency discriminator c. By a product detector d. By a phase splitter 415. What is the mixing process? a. The elimination of noise in a wideband receiver by phase

comparison b. The elimination of noise in a wideband receiver by phase differentiation c. Distortion caused by aural propagation d. The combination of the two signals to produce sum and difference frequencies 416. What is a frequency discriminator? a. A circuit for detecting FM signals b. A circuit for filtering two closely adjacent signals c. An automatic band switching circuit d. An FM generator 417. What are the principal frequencies which appear at the output of a mixer circuit? a. Two and four times the original frequency b. The sum, difference and square root of the input frequencies c. The original frequencies and the sum and difference frequencies d. 1.414 and 0.707 times the frequency 418. What occurs in a receiver when an excessive amount of signal energy reaches the mixer circuit? a. Spurious mixer products are generated b. Mixer blanking occurs c. Automatic limiting occurs d. A beat frequency is generated 419. How much gain should be used in the RF amplifier stage of a receiver? a. As much as possible short of self oscillation b. Sufficient gain to allow weak signals to overcome noise generated in the first mixer c. Sufficient gain to keep weak signals below the noise of the first mixer stage d. It depends on the amplification factor of the first IF stage 420. Why should the RF amplifier stage of a receiver only have sufficient gain to allow weak signals to overcome noise generated in the first mixer stage? a. To prevent the sum and difference frequencies from being generated b. To prevent bleed-through of the desired signal c. To prevent generation of spurious mixer products d. To prevent bleed-trough of the local oscillator 421. What is the primary purpose of an RF amplifier in a receiver? a. To provide most of the receiver gain b. To vary the receiver image rejection by utilizing the AGC c. To improve the receiver’s noise figure d. To develop the AGC voltage 422. What is an IF amplifier stage? a. A fixed-tuned passband amplifier b. A receiver demodulator c. A receiver filter d. A buffer oscillator 423. What factors should be considered when selecting an

intermediate frequency? a. A cross-modulation distortion and interference b. Interference to other services c. Image rejection and selectivity d. Noise figure and distortion 424. What is the primary purpose of the first IF amplifier stage in a receiver? a. A noise figure performance b. Tune out cross-modulation distortion c. Dynamic response d. Selectivity 425. What is the primary purpose of the final IF amplifier stage in a receiver? a. Dynamic response b. Gain c. Noise figure performance d. Bypass undesired signals 426. Which stage of a receiver primarily establishes its noise figure? a. The audio stage b. The IF stage c. The RF stage d. The local oscillator 427. What is meant by the term noise figure in a communications receiver? a. The level of noise entering the receiver from the antenna b. The relative strength of a strength of a received signal 3 kHz removed from the carrier frequency c. The level of noise generated in the front end and succeeding stages of a receiver d. The ability of a receiver to reject unwanted signals at frequencies close to the desired one 428. 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. Noise figure b. Blocking dynamic range c. Signal-to-noise ratio d. Audio output 429. What type problems are caused by poor dynamic range in a communications receiver? a. Cross-modulation of the desired signal and desensitization from strong adjacent signals b. Oscillator instability requiring frequent returning, and loss of ability to recover the opposite sideband should it be transmitted c. Cross-modulation of the desired signal and insufficient audio power to operate the speaker d. Oscillator instability and severe audio distortion of all but the strongest signal received signals 430. What is the term for the ratio between the largest tolerable receiver input signal and the minimum discernible signal?

a. Intermodulation distortion b. Noise floor c. Noise figure d. Dynamic range 431. What occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a receiver? a. Undesired signals will reach the audio stage b. Output-offset overshoot c. Cross-modulation distortion d. Filter ringing 432. How can selectivity be achieved in the front and circuitry of a communications receiver? a. By using an audio filter b. By using a pre-selector c. By using an additional RF amplifier stage d. By using an additional IF amplifier stage 433. How should the filter bandwidth of a receiver IF section compare with the bandwidth of a received signal? a. Filter bandwidth should be slightly greater than the received signal bandwidth b. Filter bandwidth should be approximately half the received signal bandwidth c. Filter bandwidth should be approximately two times the received signal bandwidth d. Filter bandwidth should be approximately four times the received signal bandwidth 434. How can receiver selectivity be achieved in the IF circuitry of a communications receiver? a. Incorporate a means of varying the supply voltage to the local oscillator circuitry b. Replace the standard JFET mixer with a bipolar transistor followed by a capacitor of the proper value c. Remove AGC action from the IF stage and confine it to the audio stage only d. Incorporate a high-Q filter 435. A receiver has a sensitivity of 0.6 microvolts and a blocking dynamic range of 60 dB. What is the strongest signal that can be present along with a 0.6 microvolt signal without blocking taking place a. 600 millivolts b. 600 microvolts c. 300 millivolts d. 300 mircovolts 436. An AM receiver is tuned to broadcast station at 600 kHz. Calculate the image rejection in dB assuming that the input filter consists of one tuned circuit with a Q of 40? a. 19.28 dB b. 39.65 dB c. 38.57 dB d. 19.83 dB 437. A receiver has two uncoupled tuned circuits before the mixer, each with a Q of 75. The signal frequency is 100.1 MHz. The IF is 10.7 Mhz. The local oscillator uses high-side

injection. Calculate the image rejection ratio. a. 23.69 dB b. 58.66 dB c. 29.33 dB d. 11.84 dB 438. What oscillator frequency is needed to heterodyne 626 kHz up to 3.58 MHz? a. 2.954 MHz b. 4.832 MHz c. 4.210 MHz d. 2.328 MHz 439. What is the undesirable effect of using too wide a filter bandwidth in the IF section of a receiver? a. Output-offset overshoot b. Undesired signals will reach the audio stage c. Thermal noise distortion d. Filter ringing 440. What is the limiting condition for sensitivity in a communications receiver? a. the noise floor of the receiver b. the power supply output ripple c. the two-tone intermodulation distorting d. the input impedance to the detector 441. What parameter must be selected when designing an audio filter using an op-amp? a. Bandwidth characteristics b. Desired current gain c. Temperature coefficient d. Output-offset overshoot 442. What two factors determine the sensitivity of a receiver? a. Dynamic range and third-order intercept b. Cost and availability c. Intermodulation distortion and dynamic range d. Bandwidth and noise figure 443. How can unwanted ringing and audio instability be prevented in a multi-section op-amp RC audio filter circuit? a. Restrict both gain and Q b. Restrict gain, but increase Q c. Restrict Q but increase gain d. Increase both gain and Q 444. What is meant by the dynamic range of a communications receiver? a. The number of kHz between the lowest and the highest frequency to which the receiver can be tuned b. The maximum possible undistorted audio output of the receiver referenced to one milliwatt c. The ratio between the minimum discernible signal and the largest tolerable signal without causing audible distortion products d. The difference between the lowest frequency signal detectable without moving the tuning knob 445. Where is the noise which primarily determines the

signal-to-noise ratio in a VHF (150 MHz) marine band receiver generated? a. In the receiver front end b. Man-made noise c. In the atmosphere d. In the ionosphere 446. An AM receiver uses a diode detector for demodulation. This enables it satisfactorily to receive a. Single-sideband, suppressed carrier (J3E) b. Single-sideband, reduced carrier (R3E) c. ISB(B8E) d. Single-sideband, full carrier (H3E) 447. Three-point tracking is achieved with a. Variable selectivity b. The padder capacitor c. Double spotting d. Double conversion 448. A receiver has poor IF selectivity. It will therefore also have poor a. Blocking b. Double-spotting c. Diversity reception d. Sensitivity 449. If a FET is used as the first AF amplifier in a transistor receiver, this will have the effect of a. Gain variation over the frequency coverage range b. Insufficient gain and selectivity c. Inadequate selectivity at high frequencies d. Instability 450. The image frequency of a superheterodyne receiver a. Is created within the receiver itself b. Is due to insufficient adjacent channel rejection c. Is not rejected by the IF tuned circuits d. Is independent of the frequency to which receiver is tuned 451. The process of impressing a low frequency information signals onto a high-frequency carrier signal is called _____. a. demodulation b. oscillation c. modulation d. amplification 452. A silicon varactor diode exhibits a capacitance of 200pF at zero bias. If it is in parallel with a 60pF capacitor and a 200-uH inductor, calculate the range of resonant frequency as the diode varies through a reverse bias of 3 to 15V. a. 679 kHz to 2.13 MHz b. 966 kHz to 1.15 MHz c. 355 kHz to 3.12 MHz d. 143 kHz to 4.53 MHz 453. A process where the received signal is transformed

into its original form. a. demodulation b. damping c. amplification d. oscillation 454. It is the process of changing the amplitude of a relative high frequency carrier signal in proportion with the instantaneous value of the modulating signal. a. frequency modulation b. digital modulation c. phase modulation d. analog modulation 455. Most of the power in an AM signal is in the a. carrier b. upper sideband c. lower sideband d. modulating signal 456. Amplitude modulation is the same as a. linear mixing b. analog multiplexing c. signal summation d. multiplexing 457. The shape of the amplitude-modulated wave is called ______. a. sidebands b. modulating signal c. envelope d. carrier signal 458. In a diode modulator, the negative half of the AM wave is supplied by a. tuned circuit b. transformer c. capacitor d. inductor 459. It is a term used to describe the amount of amplitude change present in an AM waveform. a. coefficient of modulation b. modulation index c. depth of modulation d. any of these 460. When the modulation index in an AM wave is greater than one it will cause _______. a. buck-shot b. splatter c. overmodulation d. any of these 461. The ideal value of modulation index in AM. a. 1 b. 0 c. 100 d. infinity 462. When the amplitude of the information in an AM modulator is equal to zero, what is the value of the

modulation index? a. 1 b. 0 c. 100 d. infinity 463. Amplitude modulation can be produced by 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 the amplifier 464. When the modulation index is equal to zero, the total transmitted power is equal to ________. a. one of the sidebands b. carrier c. double sidebands d. an AM wave 465. When the modulation takes place prior to the output element of the final stage of the transmitter, prior to the collector of the output transistor in a transistorized transmitter, this is called ______. a. high-level modulation b. low-level modulation c. zero-modulation d. constant modulation 466. A circuit that monitors the received signal level and sends a signal back to the RF and IF amplifiers to adjust their gain automatically. a. automatic phase control b. automatic gain control c. automatic frequency control d. automatic volume control 467. When the modulation takes place in the final element of the final stage where the carrier signal is at its maximum amplitude, it is called _____. a. constant modulation b. zero-modulation c. low-level modulation d. high-level modulation 468. If a superheterodyne receiver is tuned to a desired signal at 1000kHz and its conversion (local) oscillator is operating at 1300kHz, what would be the frequency of an incoming signal that would possibly cause image reception? a. 1600 kHz b. 2300 kHz c. 1250 kHz d. 3420 kHz 469. When modulation requires a much higher amplitude modulating signal to achieve a reasonable percent modulation, this is called a. high-level modulation b. low-level modulation c. zero-modulation

d. constant modulation 470. Amplitude modulators that vary the carrier amplitude with the modulating signal by passing it through an attenuator work on principle of a. rectification b. resonance c. variable resistance d. absorption 471. A circuit which function is to raise the amplitude of the source signal to a usable level while producing minimum nonlinear distortion adding as little thermal noise as possible. a. power amplifier b. non-linear amplifier c. buffer amplifier d. preamplifier 472. A circuit that has a low-gain, high-input impedance linear amplifier which is used to isolate the oscillator from the high-power amplifiers. a. power amplifier b. bandpass filter c. signal driver d. buffer amplifier 473. With high-level transmitters, which of the following is not a primary function of the modulator circuit? a. it provides the capacity necessary for modulation to occur b. it serves as a final amplifier c. it serves as a frequency up-converter d. it serves as a mixer 474. It is a form of amplitude distortion introduced when positive and negative alternations in the AM modulated signal are not equal. a. phase shift b. carrier shift c. amplitude variations d. frequency shift 475. A carrier is simultaneously modulated by two sine waves with modulation indices of 0.3 and 0.4, the total modulation index a. is 1 b. cannot be calculated unless the phase relations are known c. is 0.5 d. is 0.7 476. The component used to produce AM AT very high frequencies is a a. varactor b. thermistor c. cavity resonator d. PIN diode 477. It is also known as upward modulation a. carrier shift

b. amplitude variations c. frequency shift d. phase shift 478. Also known as downward modulation a. carrier shift b. amplitude variations c. frequency shift d. phase shift 479. It is a form of amplitude modulation where signals from two separate information sources modulate the same carrier frequency at the same time without interfering with each other. a. QPSK b. QUAM c. PSK d. FSK 480. A receiver has a dynamic range of 81 dB. It has 0.55nW sensitivity. Determine the maximum allowable input signal. a. 59 mW b. 69 mW c. 79 mW d. 88 mW 481. The information sources modulate the same carrier after it has been separated into two carrier signals are at 90 degrees out of phase with each other. a. QPSK b. QUAM c. PSK d. FSK 482. Demodulating quadrature AM signal requires a carrier recovery circuit to reproduce the original carrier frequency and phase and two balanced modulators to actually demodulate the signals. This is called ________. a. asynchronous detection b. quadrature demodulation c. synchronous detection d. quadrature detection 483. Quadrature amplitude modulation is also known as ________. a. phase division multiplexing b. phase division modulation c. phase amplitude multiplexing d. phase angle modulation 484. Amplitude modulation generated at a very low voltage or power amplitude is known as a. high-level modulation b. low-level modulation c. collector modulation d. minimum modulation 485. It is the first stage of the receiver and is therefore often called the receiver front end. a. mixer

b. RF section c. local oscillator d. IF stage 486. In an SSB transmitter, one is most likely to find a a. class C audio amplifier b. tuned modulator c. class B RF amplifier d. class A RF output amplifier 487. The section of the receiver than down-converts the received RF frequencies to intermediate frequencies. a. RF section b. local oscillator c. power amplifier d. mixer 488. The circuit that demodulates the AM wave and converts it to the original information signal. a. power amplifier b. local oscillator c. detector d. IF section 489. A collector modulator has a supply voltage of 48 V. The peak-to-peak amplitude of the modulating signal for 100 percent modulation is a. 24 V b. 48 V c. 96 V d. 120 V 490. What signals might feed into an FM broadcast station audio control console? a. microphones b. turntables c. remote lines d. any of these 491. The noise reduction ratio achieved by reducing the bandwidth is called a. dynamic range b. noise figure c. bandwidth efficiency d. bandwidth improvement 492. It is the minimum RF signal level that can be detected at the input to the receiver and still produce a usable demodulated information signal. a. selectivity b. sensitivity c. Q-factor d. bandwidth 493. For ideal AM, which of the following is true a. m = 0 b. m = 1 c. m < 1 d. m > 1 494. Why are limiters used in FM receivers? a. provide better noise performance

b. clip noise peaks c. prevent overdrive of discriminators d. any of these 495. Why are limiters used in FM transmitters? a. clip noise peaks b. prevent overdrive of discriminators c. prevent overdeviation d. any of these 496. It is defined as the difference in decibels between the minimum input level necessary to discern the signal and the input level that will overdrive the receiver and produce distortion. a. dynamic range b. noise figure c. bandwidth efficiency d. bandwidth improvement 497. It is the input power range over which the receiver is useful. a. dynamic range b. noise figure c. bandwidth efficiency d. bandwidth improvement 498. It is defined as the output power when the RF amplifier response is 1-dB less than the ideal linear gain response. a. 1-dB compression point b. 1-dB threshold point c. 1-dB shoot-off point d. 1-dB pinch-off point 499. It is the measure of the ability of a communications system to produce, at the output of the receiver, an exact replica of the original source information. a. sensitivity b. threshold c. selectivity d. fidelity 500. A SSB signal generated around a 200-kHz carrier. Before filtering, the upper and lower sidebands are separated by 200 Hz. Calculate the filter Q required to obtain 40-dB suppression. a. 1500 b. 1900 c. 2500 d. 2000 301. DSB 302. PIN diode 303. D 304. Sidebands 305. 3 306. Demodulation 307. mixing process whereby information is imposed upon a carrier 308. A modulator that produces a DSBSC signal 309. A circuit that acts as a variable inductance or capacitance to produce FM signals 310. By using a balanced modulator followed by a filter

311. By modulating the plate voltage of a class C amplifier 312. N 313. Mechanical filter 314. 0.799 315. 30 kHz 316. 10450 watts 317. Period 318. Modulation index 319. MF 320. Independent sideband emission 321. The only way to produce an emission F3E signal is with reactance modulator on the oscillator 322. 50% 323. In terms of peak envelope power 324. FM/TV stereo 325. Baseband frequency 326. F3E 327. Type of information to be transmitted 328. 500 W 329. Foster-Seeley discriminator 330. 11 W 331. Indirect 332. Maximum frequency swing to the highest modulating frequency 333. 0.8246 334. 0.10 milliwatts 335. Mixer 336. 0.185 V 337. Voltage-controlled oscillator 338. Distortion 339. 825 V 340. 542 W 341. Balanced modulator 342. Envelope detector 343. The need for an AFC circuit 344. Frequency synthesizer 345. Indirect 346. FM and DSB AM 347. RF amplifier 348. 230 kHz 349. The inputs are coherent 350. 48 W 351. 112.5 kHz 352. Mixer 353. Approximately equal to the circuit resistance 354. Colpitts, Hartley, and Pierce 355. Through a tapped coil 356. Through a capacitive divider 357. Through a neutralizing capacitor 358. Colpitts 359. Mechanical vibration of a crystal by the application of a voltage 360. It doesn’t require an LC tank circuit 361. Colpitts 362. It is stable 363. Efficiency = (RF power out / dc power in) x 100% 364. 14.4 ohms 365. Approximately 12 366. The back and forth oscillation of electrons in an LC circuit 367. By neutralization

368. Frequency translation 369. Balanced modulator 370. Both a and c 371. 30.8 MHz 372. Nonlinear 373. Push-push 374. Frequency synthesizer 375. both A and B 376. Indirect 377. All of the above 378. The change of the crystal oscillator frequency by loading 379. Both a and b 380. All of the above 381. SSB 382. Buffer amplifier 383. Signal bias 384. Pulse 385. Cancelling the effect of internal device capacitance 386. Splatter 387. Class C 388. Minimum IC in the same stage 389. Carrier 390. Is tuned to a harmonic of the input signal 391. 15.288 kHz 392. 7.5 V 393. 4 MHz 394. 11 MHz 395. 8 MHz 396. 185 Hz 397. 6.25 W 398. 128 ohms 399. 56. 25 W 400. 15.625 ohms 401. A reduction in receiver sensitivity because of a strong signal on a nearby frequency 402. Desensitizing 403. Quieting 404. Ensure good RF shielding between the transmitter and receiver 405. Modulation from an unwanted signal is heard in addition to the desired signal 406. Cross-modulation interference 407. By installing a filter at the receiver 408. The modulation of an unwanted signal is heard on the desired signal 409. The loudest signal received is the only demodulated signal 410. A detector that uses mixing process with a locally generated carrier 411. Capture effect 412. The recovery of intelligence from the modulated RF signal 413. Rectification and filtering of RF 414. By a frequency discriminator 415. The combination of the two signals to produce sum and difference frequencies 416. A circuit for detecting FM signals 417. The original frequencies and the sum and difference frequencies 418. Spurious mixer products are generated 419. Sufficient gain to allow weak signals to overcome noise generated in the first mixer

420. To prevent generation of spurious mixer products 421. To improve the receiver’s noise figure 422. A fixed-tuned passband amplifier 423. A cross-modulation distortion and interference 424. Selectivity 425. Gain 426. The RF stage 427. The level of noise generated in the front end and succeeding stages of a receiver 428. Blocking dynamic range 429. Cross-modulation of the desired signal and desensitization from strong adjacent signals 430. Dynamic range 431. Filter ringing 432. By using a pre-selector 433. Filter bandwidth should be slightly greater than the received signal bandwidth 434. Incorporate a high-Q filter 435. 600 microvolts 436. 38.57 dB 437. 29.33 dB 438. 2.954 MHz 439. Undesired signals will reach the audio stage 440. the noise floor of the receiver 441. Bandwidth characteristics 442. Bandwidth and noise figure 443. Restrict both gain and Q 444. The ratio between the minimum discernible signal and the largest tolerable signal without causing audible distortion products 445. In the receiver front end 446. Single-sideband, full carrier (H3E) 447. The padder capacitor 448. Blocking 449. Insufficient gain and selectivity 450. Is not rejected by the IF tuned circuits 451. modulation 452. 966 kHz to 1.15 MHz 453. demodulation 454. analog modulation 455. carrier 456. linear mixing 457. envelope 458. tuned circuit 459. any of these 460. any of these 461. 1 462. 0 463. varying the gain of the amplifier 464. carrier 465. low-level modulation 466. automatic gain control 467. high-level modulation 468. 1600 kHz 469. high-level modulation 470. variable resistance 471. preamplifier 472. buffer amplifier 473. it serves as a mixer 474. carrier shift 475. is 0.5

476. PIN diode 477. carrier shift 478. carrier shift 479. QUAM 480. 69 mW 481. QUAM 482. quadrature detection 483. phase division multiplexing 484. low-level modulation 485. RF section

486. class A RF output amplifier 487. mixer 488. detector 489. 96 V 490. any of these 491. bandwidth improvement 492. sensitivity 493. m = 1 494. any of these 495. prevent overdeviation

496. dynamic range 497. dynamic range 498. 1-dB compression point 499. fidelity 500. 2500