PINOYBIX MODULATION.pdf

April 15, 2018 | Author: Ken | Category: Frequency Modulation, Detector (Radio), Modulation, Amplifier, Electrical Circuits
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PINOYBIX MODULATION



B. vary in frequency with modulation

1. ______ is the maximum sideband suppression value using



C. vary in frequency and amplitude with

filter system.

wideband modulation



A. 50 dB



B. 60 dB

9. The process of impressing intelligence on the carrier is



C. 40 dB

called



D. 30 dB



D. is not immune to noise



A. modulation

2. _______ determines the number of sideband components in



B. detection

FM.



C. mixing



D. impression



A. carrier frequency



B. modulation frequency

10. ______ is an electronic instrument used to show both the



C. modulation index

carrier and the sidebands of a modulated signal in the



D. deviation ratio

frequency domain.

3. One of the following transmits only one sideband.



A. spectrum analyzer



A. H3E



B. oscilloscope



B. R3E



C. digital counter



C. A3E



D. frequency counter



D. B8E

4. What produces the sidebands on FM?

11. What part of the carrier is varied by the intelligence during modulation in an AM system?



A. signal amplitude



A. phase



B. carrier harmonics



B. frequency



C. baseband frequency



C. amplitude



D. broadband frequency



D. both a and c

5. Which test instrument displays the carrier and the s idebands

12. The difference between the RF carrier and the modulating

amplitude with frequency to frequency?

signal frequencies is called the



A. oscilloscope



A. USB



B. spectrum analyzer



B. LSB



C. frequency analyzer



C. Sideband



D. amplitude analyzer



D. Carrier frequency

6. Mixer is also known as a ________.

13. What stage in a radio transmitter isolates the oscillator from



A. modulator



B. suppressor



A. Oscillator



C. converter



B. Buffer



D. beater



C. Separator



D. Mixer

7. Which one of the following emission transmits the lower sideband and half of the upper sideband?

the load?

14. The frequency of the unmodulated carrier in FM s ystem is



A. A5C



A. modulating frequency



B. J3E



B. center frequency



C. A3J



C. carrier frequency



D. A3H



D. deviation frequency

8. An FM receives signal ______. 

A. vary in amplitude with modulation

15. The ratio of maximum deviation to the maximum modulating frequency is called



A. carrier swing



B. deviation ratio

22. To generate an SSB or DSB signal one must use a circuit



C. modulation factor

known as



D. modulation index

16. A carrier signal has



D. Armstrong system



A. filter modulator



B. ring modulator



A. constant amplitude



C. balanced modulator



B. a frequency of 20 kHz and above



D. reactance modulator



C. a varying amplitude



D. the information content

23. Which is the first radio receiver? 

A. TRF receiver

17. The modulated peak value of a signal is 125 V and the



B. Superheterodyne receiver

unmodulated carrier value is 85 V. W hat is



C. Crystal radio receiver

the modulation index?



D. Heterodyne receiver



A. 0.47

24. An interfering signal with a frequency equal to the received



B. 0.68

signal plus twice the IF is called



C. 0.32



A. image frequency



D. 1.47



B. center frequency

18. An 891 kHz carrier having an amplitude of 80 V is



C. rest frequency

modulated by a 4.5 kHz audio signal having an amplitude of 45



D. interference frequency

V. Themodulation factor is

25. Double sideband full carrier emission type



A. 0.56



A. A3J



B. 0.65



B. H3E



C. 1.78



C. R3A



D. 1.25



D. A3E

19. What is the modulation index of an FM signal having a

26. Single sideband reduced carrier emission type

carrier swing of 75 kHz when the modulating signal has



A. H3E

frequency of 3 kHz?



B. R3E



A. 25



C. J3E



B. 12.5



D. B8E



C. 0.04



D. 0.08

27. A single sideband suppressed carrier emission type. 

A. H3e

20. In a FM system, if modulation index is doubled by having



B. R3E

the modulating frequency, what will be the effect on the



C. J3E

maximum deviation?



D. B8E



A. No effect



B. Maximum deviation doubles



A. H3E



C. Decreases by ½



B. R3E



D. Increases by ¼



C. J3E



D. B8E

21. Which of the following is considered as an indirect method of generating FM?

28. Independent sideband emission type

29. Vestigial sideband emission type



A. Reactance modulator



A. C3F



B. Balanced modulator



B. J3E



C. Varactor diode modulator



C. R3E



D. B8E

30. Single sideband full carrier emission type.



D. B3E

38. AM transmission power increases with ________.



A. R3E



A. Frequency



B. H3E



B. Source



C. J3E



C. Load



D. B8E



D. Modulation

31. Phase modulation emission type.

39. _______ locks the FM receiver to a stronger signal.



A. F3E



A. Hall effect



B. F3C



B. Capture effect



C. F3F



C. Image frequency



D. G3E



D. Homing

32. Which one is not an advantage of SSB over AM?

40. What is the highest percentage of modulation for AM?



A. Power saving



A. 50 %



B. Requires half the bandwidth



B. 75 %



C. Wider area of reception



C. 100 %



D. Better fidelity



D. 80 %

33. The advantage of a high level modulated AM transmitter is

41. In FM, the Carson’s Rule states that the bandwidth is equal



A. Less audio power required



B. Better fidelity



A. Carrier signal



C. Higher value of operating power



B. Modulating signal



D. Less distortion



C. Frequency deviation



D. Image frequency

34. The advantage of a low-level modulated AM transmitter is

to twice the sum of the modulating frequency and ______.



A. Less audio power required

42. What is the carrier swing of an FM transmitter when



B. Better fidelity

modified by 75%?



C. Higher value of operating power



A. 53.2 kHz



D. Less distortion



B. 48 kHz

35. _____ is the bad effect caused by overmodulation in AM



C. 56.25 kHz

transmission.



D. 112.5 kHz



A. Increase in noise



B. Deviation in the operating frequency



A. Single sideband suppressed carrier



C. Interface to other radio services



B. Frequency modulation



D. Decrease in the output power



C. Pulse-position modulation



D. Amplitude shift keying

36. Which characteristic of a radio receiver refers to its ability to reject an unwanted signal?

43. The modulation system inherently more resistant to noise

44. Subcarriers that are arranged so that the c hannels



A. Sensitivity

occupying adjacent frequency bands with some frequency



B. Selectivity

space between them is known as



C. Fidelity



A. Guard bands



D. Quality



B. AM bands



C. Band gap



D. Void band

37. What type of emission is frequency modulation? 

A. F3E



B. G3E



C. A3E

45. Modulation of an RF amplifier carrier results in 

A. Multiple channels



B. Smaller antennas

53. When a carrier is modulated 100%, the total power



C. Directional propagation

increases by what percentage over that of the carrier alone?



D. All of the above

46. A process which occurs in the transmitter



A. 25 %



B. 50 %



A. Mixing



C. 75 %



B. Modulation



D. 100 %



C. Heterodyning

54. When the amplitude of the modulating voltage is increased



D. Demodulation

for AM, the antenna current will

47. A process which occurs in the receiver



A. Increase



A. Beating



B. Decrease



B. Modulation



C. Remain constant



C. Mixing



D. Decrease exponentially



D. Demodulation

48. One part of the transmitter that protects the crystal

55. An increase in transmitter power from 25W to 30W will cause the antenna current to increase from 700mA to

oscillator from “pulling”.



A. 800 mA



A. Buffer amplifier



B. 750 mA



B. Modulator



C. 767 mA



C. Power amplifier



D. 840 mA



D. Antenna coupler

49. What aspect of the carrier is c hanged by modulation?

56. A second modulating tone having the same amplitude but a different frequency is added to the first at the input to the



A. Frequency

modulator. The modulation index will be increased by a factor



B. Phase

of



C. Amplitude



A. sq. root of 3



D. Depends on the type of modulation



B. sq. root of 2

50. The amplitude of a sine wave which is modulated by a



C. 2

musical program will



D. 3



A. Be complex

57. A 1000 kHz carrier is modulated by a 2500Hz tone. One



B. Contain fundamental frequencies

frequency component of the modulated signal is



C. Contain harmonic frequencies



A. 1200 Hz



D. All of the above



B. 5000 Hz

51. What will be the result of the gain level being too high for



C. 1002.5 kHz

signals entering the modulator?



D. 2500 Hz



A. Receiver noise

58. A 1200 kHz carrier is amplitude-modulated by two tones of



B. Excessive volume of receiver output

500 Hz and 700 Hz. W hich one is a frequency component of



C. Oscillator disturbances

the modulated wave?



D. Distortion and splatter



A. 1195 kHz

52. Amplitude modulation causes the amount of transmitter



B. 1199.3 kHz

power to



C. 1199.7 kHz



D. 1205 kHz



A. Increase



B. Decrease

59. Identify a modulation method, or methods in use for a



C. Remain the same

common-emitter configuration



D. Double



A. Base modulation



B. Emitter modulation

67. In FM, the change in carrier frequency is proportional to



C. Collector modulation

what attribute of the modulating signal?



D. Both A and C



A. Angle

60. The RF signal injected into a balanced modulator is 10MHz



B. Frequency

and the modulating frequency is 1 kHz. W hich frequency, or



C. Amplitude

frequencies, will not appear in the output?



D. Tone



A. 9.999 MHz

68. A louder sound, when generating the modulating waveform



B. 10 MHz

for FM, will cause a greater



C. 10.0001 MHz



A. Carrier amplitude



D. Both A and B



B. Angle amplitude

61. Unwanted sidebands in SSB equipment can be



C. Distortion at the receiver

suppressed by one or more of the following methods.



D. Frequency deviation



A. Phasing method

69. If a positive change in modulation signal level of 200 mW



B. Filter method

will cause a positive frequency deviation of 10 kHz, what will



C. Decoder method

be the frequency deviation for a negative change of 10 mV in



D. Both A and B

the level of the modulating signals?

62. Envelope detection is concerned with the process of



A. 0



A. Mixing



B. -5 kHz



B. Heterodyning



C. +5 kHz



C. Modulation



D. +0 kHz



D. Rectification

63. Diagonal clipping in envelope detection will result in

70. A particular 15 kHz modulation tone results in a peak frequency deviation of 75 kHz. What is the modulation index?



A. Distortion



A. 5



B. Phase reversal



B. 15



C. Reduced sensitivity



C. 75



D. Amplitude damage



D. 3

64. Product detection requires the process of

71. A 15 kHz sine wave frequency modulates an 88 MHz



A. Rectification



B. Heterodyning



A. 87.970 MHz



C. Decoding



B. 87.985 MHz



D. Phase shifting



C. 88.015 MHz



D. All of these

65. A sine wave which is coherent with carrier has identical

carrier. A sideband frequency will be found at



A. Amplitude

72. A device whose capacitance is deliberately made to be a



B. Frequency

function of the applied voltage



C. Phase angle



A. Varactor diode



D. Both B and C



B. UJT

66. Frequency modulation and phase modulation are



C. SAW

collectively referred to as



D. Variable capacitor



A. Stereo

73. A reactance modulator is one method of obtaining



B. Angle modulation



A. Indirect FM



C. High fidelity modulation



B. Direct FM



D. FCC modulation



C. Demodulation



D. Low frequency filtering

81. A quadrature detector requires that

74. A device, now available in IC form, is useful for direct FM



A. Four gates bee provided

and as one element in the phse-locked loop.



B. The inputs are coherent



A. AFC



C. The inputs are incoherent



B. AGC



D. The inputs are identical



C. VCO



D. LPF

82. In a phase-locked loop, the VCO is the abbreviation for 

A. Variable coherent output

75. _____ is a frequency change process , whereby the phase



B. VHF communication oscillator

deviation and frequency deviation are multiplied by some fixed



C. Voltage-controlled oscillator

constant.



D. Vien-count oscillator (neutralized)



A. Translation

83. Identify an advantage, or advantages of a properly



B. Multiplication

designed FM system.



C. Division



A. Relative immunity to atmospheric noise (lightning)



D. Addition



B. Reduced bandwidth required

76. A circuit that has the function of demodulating the



C. No noise of any kind

frequency-modulated signal.



D. The noise figure is inversely proportional to the



A. AFC



B. Envelope detector



C. Decoder



A. LSB and USB



D. Foster-Seeley discriminator



B. LSB



C. USB



D. Carrier

77. The ratio detector is superior to the slope detector because

modulation index 84. The output of a balanced modulator



A. It is less sensitive to phase modulation



B. It is less sensitive to noise spikes

85. If the modulation index of an AM wave is changed from 0 to



C. It is less sensitive to interference causing AM

1, the transmitted power is



D. Both B and C

78. One implementation of a pulse averaging discriminator is



A. Unchanged



B. Halved



A. A free-running multivibrator



C. Doubled



B. A crystal-controlled oscillator



D. Increased by 50%



C. A quartz crystal filter

86. Which of the following is not a baseband signal of



D. A triggered multivibrator

modulation?

79. A 10% increase in the frequency of a constant-width pulse



A. Audio signal

train should cause what change in its average value?



B. Video signal



A. –10 %



C. RF carrier



B. –1 %



D. Binary coded pulses



C. +1 %

87. If the unmodulated level peak carrier amplitude is doubled



D. +10 %

in an AM signal, the perfect modulation is ________.

80. Two different signals can be coherent if they



A. 20



A. Have the same amplitude



B. 50



B. Are both sine waves of different frequencies



C. 100



C. Originate in the same physical equipment



D. 200



simultaneously

88. Balanced modulator circuit when inserted in the equivalent

D. Have the same frequency

suppresses the ___________



A. Carrier



B. Twice the srcinal index



B. Upper sideband



C. Four times the srcinal index



C. Lower sideband



D. One-half the srcinal index



D. Baseband signal

89. The carrier of a 100% modulated AM wave is suppressed, the percentage power saving is __.

96. An AM transmitter is rated 1000 W at 100% modulation. How much power required for the carrier? 

A. 1000 W



A. 100 %



B. 666.6 W



B. 50 %



C. 333.3 W



C. 83 %



D. 866.6 W



D. 66.66 %

97. Standard way of designating AM

90. If the modulation index if an AM wave is doubled, the



A. A3E

antenna current is also doubled, the AM system being used is



B. B3E



A. H3E



C. AHE



B. J3E



D. C3F



C. C3F

98. _____ is the circuit used to detect frequency modulated



D. A3E

signal.

91. 100% modulation in AM means a corresponding increase



A. Discriminator

in total power by _______.



B. Modulator



A. 100 %



C. Modem



B. 50 %



D. Detector



C. 75 %

99. _____ is an information signal that is sent directly without



D. 25 %

modulating any carrier.

92. A single-tone amplitude modulated wave has _______.



A. C-band



A. 2 components



B. Q-band



B. 3 components



C. Baseband



C. 4 components



D. Broadband



D. 2n + 1 components

93. A carrier signal has ________.

100. Both frequency and phase modulation utilize ______ modulation.



A. Constant peak amplitude



A. Digital



B. Frequency range of 20 – 20,000 Hz



B. Phase



C. A varying amplitude



C. Amplitude



D. The information



D. Angle

94. The modulating system is _________ if the modulating

01. It is the width of frequencies within the spectrum occupied

frequency is doubled, the modulation index is halved, and the

by a signal and used by the signal for conveying information.

modulating voltage remains constant.



A. Band



A. Amplitude modulation



B. Bandwidth



B. Phase modulation



C. Electronic spectrum



C. Frequency modulation



D. Frequency band



D. Pulse modulation

102. Which transmit only one sideband?

95. What is the modulation index of an FM signal if its



A. H3E

modulating frequency is doubled?



B. C3F



C. A3E



A. No effect



D. B8E

103. ______ is kind of modulation in which the modulated wave is always present.



C. Low-Q tank circuit



D. IF strip

110. If the frequency of each component in a signal spectrum



A. Carrier modulation



B. Continuous modulation



A. Modulation



C. Log-periodic modulation



B. Frequency translation



D. Square-wave modulation



C. Up conversion



D. Both B and C

104. A type of modulation in which no signal is present between pulses.

is increased by the same fixed a mount, this known as

111. A particular amplifier is designed to be a frequency



A. Pulse modulation

doubler. If the input signal frequency is 15.4 MHz, a circ uit in



B. FSK

the output will be tuned to



C. QAM



A. 7.7 MHz



D. PAM



B. 15.4 MHz

105. What describes the amount of amplitude change pre sent



C. 30.8 MHz

in an AM waveform?



D. 61.6 MHz



A. Percent modulation

112. A sine wave of 293 MHz is phase-modulated to achieve a



B. Modulation constant

maximum phase deviation of 0.2 radian. After passing through



C. Envelope of modulation

a frequency tripler, the maximum phase deviation will be



D. Coefficient of modulation



A. 0.2 radian

106. _______ is a form of amplitude distortion introduced when



B. 0.3 radian

the positive and negative alternations in the AM modulated



C. 0.4 radian

signals are not equal.



D. 0.6 radian



A. Envelope distortion



B. Spurious emission



A. Active



C. Carrier shift



B. Passive



D. Johnson noise



C. Linear



D. Nonlinear

107. What is the advantage of phase modulation over direct FM frequency modulation?

113. Any device to be used as a frequency multiplier must be

114. A particular amplifier circuit used for frequency doubling.



A. Multipliers can be used



A. Push-push



B. The deviation is smaller



B. Push-pull



C. Simplicity and practicality



C. Pull-push



D. The oscillator is crystal-controlled



D. Pull-pull

108. If the spectrum is shifted in frequency with no other changes, this is known as

115. Frequency division is useful in the implementation of a 

A. AM demodulator



A. Frequency multiplication



B. Frequency synthesizer



B. Sideband movement



C. AGC circuit



C. Baseband reorientation



D. FM demodulator



D. Frequency translation

109. A device which is capable of causing frequency translation

116. Frequency division by 12 will require how many flip-flops in the counter? 

A. 3



A. High-Q tank circuit



B. 4



B. Balanced modulator



C. 6



D. 12

117. Identify an electronic device, not specifically designed for

124. A receiver in which all RF amplifier stages require manual tuning to the desired RF is called

the purpose, which can be used as a phase detector.



A. Superheterodyne



A. Wien bridge



B. Autodyne



B. Colpitts oscillator



C. TRF



C. Balanced modulator



D. AFC



D. Butterworth filter

118. A particular frequency synthesizer contains only a s ingle

125. Why is it often necessary to precede the demodulator by amplifier stages in a receiver?

crystal. What words describe this synthesizer?



A. To improve fidelity



A. Crystal modulated



B. To reduce receiver noise



B. Inexact



C. To eliminate image response



C. Indirect



D. Weak antenna signals



D. Deficient

126. A serious disadvantage of the TRF receiver.

119. A recognizable feature of a CW transmitter is



A. Bandwidth variations over the tuning range



A. Keyed transmitter



B. The weight and cost



B. Power amplification



C. The requirements for a closely regulated power



C. Frequency generation



D. All of these

120. The term “pulling” refers to

supply 

D. The requirements for a half-wave antenna

127. Identify which is not a part of a s uperheterodyne receiver.

A. The change of the crystal oscillator frequency by



A. Local oscillator

loading



B. Modulator



B. One half-cycle operation of a push-pull amplifier



C. IF amplifier



C. Loading on the transmitter caused by



D. Demodulator





the antenna connection

128. Which major element will not be found in e very

D. Reduction of the power supply terminal voltage as

superheterodyne receiver? 

A. R–F amplifier

121. When frequency modulation is achieved by initial



B. Mixer

phase modulation, this is called



C. Local oscillator



A. Angular modulation



D. IF amplifier



B. Direct FM

129. Which major element of a superheterodyne receiver must



C. Indirect FM

be nonlinear?



D. Indirect synthesis

the transmitter is keyed.

122. A disadvantage of direct FM is the need for



A. R-F amplifier



B. Mixer



A. AGC



C. Local oscillator



B. AFC



D. IF amplifier



C. A frequency synthesizer

130. The change of the modulated carrier frequency from the



D. Phase modulation

srcinal RF to the IF of the superheterodyne receiver is known

123. Direct FM can be achieved by

as



A. A reactance tube modulator



A. Frequency multiplication



B. A varactor diode



B. Frequency allocation



C. And AGC circuit



C. Frequency substitution



D. Both A and B



D. Frequency translation

131. The key to achieving receiver s ensitivity is the reduction



C. The image frequency

of



D. The image rejection ratio



A. Image response



B. Mixer harmonic products



A. Teflon



C. Spurious frequency response



B. Computer nylon



D. Internal noise



C. Powdered iron



D. Laminated steel

132. Which of the following receiver design objectives is not impossible?

138. The core of an IF transformer usually c ontains

139. Shape factor is a measure of



A. Elimination of galactic noise



A. Bandwidth



B. Elimination of atmospheric noise



B. Skirt steepness



C. Elimination of man-made noise



C. Coupling coefficient



D. Reduction of receiver internal noise



D. Critical coupling

133. In comparing the S/N ratio for the input to the receiver

140. _______ is the function which tends to maintain the sound

with the S/N ratio for the output, the latter is

volume level of a voice receiver nearly constant for a large



A. Smaller



B. The same



A. Squelch



C. Greater



B. Muting



D. Infinite



C. AGC



D. AFC

134. The characteristic of a receiver that specifies the self generated noise.

signal strength range.

141. The function which tends to silence the receiver in the



A. Noise immunity



B. Noise factor



A. Squelch



C. Noise figure



B. Muting



D. Noise margin



C. AGC



D. AFC

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?

absence of transmitted carrier.

142. What device is incorporated in a communications receiver



A. 77.3 MHz



B. 88.0 MHz



A. Front-end processor



C. 109.4 MHz



B. Squelch circuit



D. 120.1 MHz



C. AGC



D. Noise blanker

136. A source of RF interference exists at 109.9 MHz. For

to reduce impulse noise?

which frequency in the FM broadcast band will this be the

143. What type of signal in which a receiver selectivity of 2.4

image frequency?

kHz in the I-F circuitry is optimum?



A. 21.4 MHz



A. FM voice



B. 88.5 MHz



B. Double-sideband AM voice



C. 99.2 MHz



C. FSK data



D. 110.7 MHz



D. SBB voice

137. The ratio of the superheterodyne receiver response at the

144. If the input to a detector stage is an amplitude-modulated

desired carrier frequency to that at the image frequency is

(A3E) IF signal then the output from the stage is

called



A. A lower frequency carrier



A. The sensitivity



B. The audio voice information



B. The selectivity



C. A Morse-code signal



D. The upper or lower set of sidebands

145. In a capacitive type, reactance-tube modulator connected

151. An effect in which, the modulation of an unwanted signal is transferred to the desired carrier.

across an oscillator tuned circuit, a more negative voltage on



A. Crossmodulation

the grid of the reactance tube will cause



B. Intermodulation



A. An increase of the oscillator frequency



C. Modulation mixing



B. An decrease of oscillator frequency



D. Image-channel interference



C. An increase of the reactance-tube c apacitance

152. Leads should be kept as s hort as possible in radio circuit



D. An increase of the reactance tube ac plate current

so that

146. The limiting condition for sensitivity in a communications



A. Skin effect is reduced

receiver is



B. There is less hysteresis e ffect



A. The noise floor of the receiver



C. There is less dielectric loss



B. Power supply output ripple



D. Stray coupling is minimized



C. The two-tone intermodulation distortion

153. The number of voice transmissions that can be packed



D. The input impedance to the detector

into a given frequency band for amplitude-compandored

147. When a communications receiver is tuned to a strong

single-sideband systems over conventional FM-phone

signal, the AGC bias is measured and found to be zero. The

systems.

fault cannot be caused by a/an



A. 2



A. Defective IF stage



B. 18



B. Defective local oscillator



C. 16



C. Defective RF stage



D. 4



D. Open circuit in the AGC’s filter capacitor

148. The term used to refer to the condition where the signals

154. Neutralization of an RF amplifier stage can be necessary in order to

from a very strong s tation are superimposed on other signals



A. Increase the amplifier’s gain

being received



B. Prevent the generation of spurious oscillations



A. Cross-modulation interference



C. Reduce the amplifier’s gain



B. Intermodulation interference



D. Reduce the level of the output harmonics



C. Receiver quieting

155. The ability of a communications receiver to perform well in



D. Capture effect

the presence of strong signals outside the band of interest is

149. The limiter stage of an FM receiver

indicated by what parameter?



A. Behaves as a low-pass filter



A. Blocking dynamic range



B. Limits the amplitude of the IF signal to the required



B. Noise figure

level



C. Signal-to-noise ratio



C. Behaves as a high-pass filter



D. Audio output



D. Behaves as a bandstop filter

156. Stages that are common to both AM and FM receivers

150. Motorboating (low-frequency oscillations) in an amplifier



A. Tuner, local oscillator, detector, AF amplifier

can be stopped by



B. RF amplifier, mixer, IF amplifier, AF amplifier



C. Local oscillator, RF amplifier, frequency



A. Grounding the screen grid



B. Connecting a capacitor between the B+ and lead ground





discriminator, detector 

D. Tuner, IF amplifier, detector, AF amp

C. By passing the screen grid resistor with a 0.1 µF

157. Occurs during CW reception if too narrow a filter

capacitor

bandwidth is used in the IF stage of a receiver

D. Grounding the plate



A. Filter ringing



B. Undesired signals will reach the audio s tage



A. In the detector



C. Output-offset overshoot



B. In the atmosphere



D. Cross-modulation distortion



C. In the ionosphere



D. In the receiver front end

158. What stage mainly determines a communication receiver’s sensitivity?

165. Cross-modulation in a receiver can be reduced by



A. IF amplifier



A. Installing a filter at the receiver



B. Mixer stage



B. Using a filter at the receiver



C. Detector stage



C. Increasing the receiver’s RF gain while decreasing



D. RF amplifier

159. What is the main advantage of FM over A M?

the AF 

D. Adjusting the pass-band tuning



A. Better signal-to-noise-ratio



B. Narrower bandwidth



A. F3E



C. Greater propagation range



B. G3E



D. Total freedom from adjacent-channel interference



C. J3E



D. H3E

160. An amplitude modulation created in an amplifier before the final RF stage.

166. What is the emission designation for FM telephony?

167. What is the cause of receiver de sensitizing?



A. Low-level modulation



B. High-level modulation



C. Direct modulation



B. Audio gain adjusted too low



D. Indirect modulation



C. Squelch gain adjusted too high



D. Squelch gain adjusted too low

161. Receiver desensitizing can be reduced by



A. The presence of a strong signal on a nearby frequency



A. Increasing the transmitter audio gain

168. In a phase-modulated signal (indirect FM), the frequency



B. Decreasing the receiver squelch gain

deviation is directly proportional to the



C. Increasing the receiver bandwidth



A. Carrier amplitude only



D. Ensuring good RF shielding between the



B. Amplitude of the modulating tone and frequency of

transmitter

the carrier

162. In a narrow-band FM system, the deviation ratio is



C. Carrier frequency only

commonly one and the highest audio frequency is generally



D. Modulating signal amplitude only

limited to

169. An RF stage precedes the mixer stage in a



A. 300 Hz

superheterodyne receiver. One advantage of including this RF



B. 10,000 Hz

stage is



C. 3,000 Hz



A. Better selectivity



D. 7,500 Hz



B. Better rejection ratio

163. A type of emission is produced when an amplitude



C. Greater sensitivity

modulated transmitter is modulated by a facsimile signal



D. Improved signal-to-noise-ratio



A. A3F



B. F3F



A. Dynamic range and third-order intercept



C. A3C



B. Cost and availability



D. F3C



C. Bandwidth and noise figure



D. Intermodulation distortion and dynamic range

164. Where is the noise generated which primarily determines

170. Two factors that determine the sensitivity of a receiver.

the signal to noise ratio in a VHF (150 MHz) marine band

171. What is an undesirable effect of using too-wide a filter

receiver?

bandwidth in the IF section of a receiver?



A. Undesired signals will reach the audio stage



A. Avoid the requirement of neutralizing the stage



B. Output-offset overshoot



B. Raise the input impedance



C. Thermal-noise distortion



C. Lower the output impedance



D. Filter ringing



D. Obtain maximum power output

172. A system containing a limiter stage, a disc riminator, and a

179. The AM detector performs two basic functions in the

de-emphasis circuit?

receiver.



A. Direct FM transmitter



A. Rectifies and filters



B. Indirect FM transmitter



B. Amplifiers and filters



C. Single sideband AM receiver



C. Buffer and amplifier



D. FM receiver



D. Buffer and detector

173. The limiter stage of an FM receiver

180. A varactor diode can be used in a/an



A. Prevents any amplitude modulation of the IF signal



A. Direct FM modulator circuit



B. Limits the amount of frequency deviation in the IF



B. AFC circuit in a direct FM transmitter

signal



C. Phase-modulator circuit



C. Limits the overall bandwidth of the IF stages



D. All of these



D. Corrects any deviation in carrier frequency

181. Receiver interference is not reduced by including a/an

174. High selectivity occurs when the degree of c oupling



A. Crystal filter

between a receiver’s RF stages is



B. Insulating enclosures around the receiver



A. Tight



C. Wave trap



B. Loose



D. RF stage



C. Critical



D. Adjusted for maximum power transfer

182. What is the emission C3F? 

A. RTTY

175. A carrier is phase modulated by a test tone. If the



B. SSB

amplitude and the frequency of the tone are both doubled, the



C. Television

amount of the deviation is



D. Modulated CW



A. Doubled

183. What is the approximate dc input power to a class AB RF



B. Unchanged

power amplifier stage in an unmodulated carrier transmitter



C. Halved

when the PEP output is 500 W?



D. Multiplied by four



A. Approximately 1000 W

176. The degree of selectivity desirable in the IF circuitry of a



B. Approximately 800 W

single-sideband receiver.



C. Approximately 250 W



D. Approximately 600 W



A. 1 kHz



B. 2.4 kHz

184. Which of the following stages in an FM receiver is



C. 4.2 kHz

responsible for drastically reducing the effect of static noise



D. 4.8 kHz

during the reception of a signal

177. The component most apt to break down in the radio circuit



A. De-emphasis circuit

is the



B. Mixer stage



A. Crystal



C. Squelch circuit



B. Resistor



D. Limiter stage



C. Transformer



D. Diode

178. The base in an RF amplifier is grounded in order to

185. The letters “SSSC” stands for 

A. Single sideband, single carrier



B. Suppressed sideband, single channel



C. Suppressed sideband, single carrier



B. Installing capacitive spark plugs



D. Single sideband, suppressed carrier



C. Installing resistors in series with the spark plugs



D. Installing two copper-braid ground strips

186. For many types of voices, what is the ratio of PEP-toaverage power during a modulation peak in a single-sideband phone signal? 

A. Approximately 1.0 to 1



B. Approximately 25 to 1



C. Approximately 100 to 1



D. Approximately 2.5 to 1

187. In most mixers, the oscillator frequency is ______ than the carrier frequency of the input signal.

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. Higher



A. Local oscillator



B. Lower



B. Mixer stage



C. The same



C. Final IF amplifier, which also acts as a limiter stage



D. 10 kHz above



D. Buffer

188. Features of a transmitter’s buffer stage include

195. In an FM receiver, the stage that has the IF signal is input



A. High stage



B. Harmonic generation



A. Limiter



C. Improvement in frequency stability of the oscillator



B. Audio amplifier



D. Low input impedance



C. IF amplifier



D. Discriminator

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 



B. A power incidence network



C. An antenna matching network that is isolated from ground



191. How is G3E FM-phone signals produced? A. A network consisting modulator on the audio

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 

D. A network consisting of one inductor and two capacitors



196. What is capture effect?

A. A network consisting entirely of four inductors or four capacitors



and the audio signal output.

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

amplifier

198. Pre-emphasis is used in FM transmitters to improve the



B. With a reactance modulator on the final amplifier

signal-to-noise ratio of



C. With a reactance modulator on the oscillator



A. High modulating frequencies



D. With a balanced modulator on the oscillator



B. Low modulating frequencies



C. All modulating frequencies



D. Frequencies carrier

192. A way of eliminating auto interference to radio reception 

A. Installing resistive spark plugs

199. The result of cross-modulation is that 





B. Bandwidth of emission and occupied bandwidth

A. The modulation of an unwanted signal is heard on



C. Operating bandwidth

the desired signal



D. All of these

B. A decrease in modulation level of transmitted

206. A class-C RF amplifier is collector amplitude modulated

signals

and its average dc level collector current does not change.



C. Of receiver quieting

This means



D. Of inverting sidebands in the final stage of the



A. A normal condition

amplifier



B. Excessive drive to the base



C. Insufficient drive to the base



D. Insufficient audio modulation

200. Which of the following contains de-emphasis circuit? 

A. FM transmitter



B. FM receiver

207. What determines the percentage modulation of an FM



C. VHF transmitter

transmitter?



D. VHF receiver

201. What is emission F3F?



A. Amplitude of the carrier



B. Modulating frequency



A. AM



C. Carrier frequency



B. Facsimile



D. Amplitude of the modulating signal



C. Television



D. RTTY

208. Deviation ratio of an FM transmitter is the ratio of the 

202. What type of emission is produced when a frequency modulated transmitter is modulated by a facsimile signal?

A. Maximum frequency swing to the highest modulating frequency



B. Operating frequency of the assigned frequency



A. F3C



C. Frequency swing to the modulating frequency



B. A3C



D. Highest modulating frequency to the minimum



C. F3F



D. A3F

203. Two AM transmitting antennas are close together. As a

frequency 209. The main purpose of the beat frequency oscillator (BFO) is to generate

result the two modulated signals are mixed in the final RF



A. A 1 kHz not for Morse reception

stage of both transmitters. What is the resultant effect on other



B. Aid in the reception of weak voic e-modulated

station?

signals



A. Harmonic interference



B. Intermodulation interference



C. Spurious interference



D. Crossmodulation interference



C. An output, whose frequency differs from the IF by 1 kHz



D. A signal, whose frequency is the same as intermediate frequency

204. The term used to refer to the reduction of receiver gain

210. Normally, a linear class BRF power amplifier operates

caused by the signal of a nearby station transmitter in the

with a bias approximately equal to

same frequency band?



A. Twice cut-off



A. Quieting



B. Ten times cut-off value



B. Cross-modulation interference



C. 50% of cut-off value



C. Squelch gain rollback



D. Projected cut-off



D. Desensitizing

205. What is the bandwidth occupied by the carrier, both sidebands and harmonics? 

A. Authorized bandwidth

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



A. Zero beat



D. Amplify of an AM signal



B. Under-modulation

212. The term used to refer to the condition where the signal



C. Zero-modulation

from a very strong s tation are superimposed on other signal



D. Over-modulation

being received.

219. What is the approximate bandwidth of an FM with a



A. Cross-modulation interference

modulation factor of 12.5 and a modulating frequency of 10



B. Intermodulation distortion

kHz?



C. Receiver quieting



A. 20 kHz



D. Capture effect



B. 270 kHz

213. _________ is the amplitude of the maximum negative



C. 250 kHz

excursion of a signal as viewed on an oscilloscope.



D. 45 kHz



A. Peak-to-peak voltage



B. Inverse peak positive voltage



A. Linear mixing



C. RMS voltage



B. Analog multiplication



D. Peak negative voltage



C. Signal summation



D. Multiplexing

214. The type of emission that suffer most from s elective fading.

220. Amplitude modulation is the same as

221. The negative half of the AM wave is supplied by a/an



A. CW and SSB



B. SSB and TV



A.



C. FM and double sideband AM



B. Transformer



D. SSTV and CW



C. Capacitor



D. Inductor

215. In an FM-phone signal, ________ is the ratio between the actual frequency deviation to the maximum frequency deviation.

_______ on a diode modulator.

222. One of the following can produce AM. 

A. Having the carrier vary a resistance



A. FM compressibility



B. Having the modulating signal vary a capacitance



B. Modulating index



C. Varying the carrier frequency



C. Percentage of modulation



D. Varying the gain of an amplifier



D. Quieting index

223. Amplitude modulators that vary the carrier amplitude with

216. _______ is used to refer to the reception blockage of one

the modulating signal by passing it through an attenuator

FM-phone signal by another FM-phone signal.

network is the principle of



A. Capture effect



A. Rectification



B. Desensitization



B. Amplification



C. Cross-modulation interference



C. Variable resistance



D. Frequency discrimination



D. Absorption

217. A receiver selectivity of 10 kHz in the IF circuitry is

224. Which component is used to produce AM at very high

optimum for what type of signals?

frequencies?



A. SSB voice



A. Varactor diode



B. Facsimile



B. Thermistor



C. FM



C. Cavity resonator



D. Double-sideband AM



D. PIN diode

218. If the envelope of modulation is constant in amplitude this means

225. A collector modulator has a supply voltage of 48 V. What



B. Rectifier

is the peak-to-peak amplitude of the modulating signal for 100



C. Bridge

percent modulation?



D. Constant current source



A. 24 V



B. 48 V



A. LC networks



C. 96 V



B. Mechanical resonators



D. 120 V



C. Crystals



D. RC networks and op amps

226. What circuit recovers the srcinal modulating information from an AM signal?

233. The most commonly used filter in SSB generators uses

234. In the phasing method of SSB generation, one sideband



A. Modulator



B. Demodulator



A. Phase shifting



C. Mixer



B. Sharp selectivity



D. Crystal set



C. Carrier suppression



D. Phase inversion

227. What is the most commonly used amplitude demodulator?

is canceled out due to



A. Envelope detector

235. A balanced modulator used to demodulate a SSB signal



B. Balanced modulator

is call a/an



C. Mixer



A. Transponder



D. Crystal set



B. Product detector

228. What circuit generates the upper and lower sidebands



C. Converter

and suppresses the carrier?



D. Remodulator



A. Amplitude modulator



B. Diode detector



A. Summer



C. Class C amplifier



B. Multiplier



D. Balanced modulator



C. Divider



D. Mixer

229. _________ is a widely used balanced modulator.

236. Frequency translation is done with a circuit called a



A. Diode bridge circuit



B. Full-wave bridge rectifier



A. Rectification



C. Lattice modulator



B. AM



D. Balanced bridge modulator



C. Linear summing



D. Filtering

230. In a diode ring modulator, the diodes act like

237. Mixing for frequency conversion is the same as



A. Variable resistors

238. Which of the following is not a major advantage of FM



B. Switches

over AM?



C. Rectifiers



A. Greater efficiency



D. Variable capacitors



B. Noise immunity



C. Capture effect



D. Lower complexity and cost

231. The output of a balanced modulator is 

A. AM



B. FM



C. SSB



A. Higher cost and complexity



D. DSB



B. Excessive use of spectrum space

232. The principal circuit in the popular 1496/1596 IC balanced



C. Noise susceptibility

modulator is a



D. Lower efficiency



A. Differential amplifier

239. The primary disadvantage of FM is its

240. Noise is primarily



A. High-frequency spikes



B. BFO



B. Lowe-frequency variations



C. Ratio detector



C. Random level shifts



D. All of these



D. Random frequency variations

241. The receiver circuit that rids FM of noise is the

249. Which of the following is the most widely used amplitude modulator



A. Modulator



A. Diode detector



B. Demodulator



B. PLL circuit



C. Limiter



C. VCO



D. Low-pass filter



D. All of these

242. The AM signals generated at a low level may only be

250. Which of the following is the most widely used balanced

amplified by what type of amplifier?

modulator



A. Class A



A. Full-wave bridge circuit



B. Class B



B. Balanced bridge modulator



C. Class C



C. Lattice modulator



D. All of the above



D. None of these

243. SSB means

251. A method that applied the modulated wave to the vertical



A. Single sideband with suppressed carrier

deflection circuit of the oscilloscope and the modulating signal



B. Single sideband with carrier

to the horizontal deflection circuit.



C. Double sideband with no carrier



a. Trapezoidal method



D. Single sideband with reduced carrier



b. Circular method



c. Square method



d. Any method

244. A circuit used to select the desired output from a mixer 

A. Transformer



B. Resonant circuit

252. The heart of all methods of single-s ideband modulation



C. Filter

and demodulation



D. Phase-shift circuit

245. What is the output of a balanced modulator?



a. Modulator



b. Balanced modulator



A. AM



c. Modulation



B. DSB



d. demodulation



C. SSB

253. If the frequency and phase are parameters of carrier



D. ISB

angle, which is a function of time, the general term

246. The acronym SSSC refer to

___________-cover both.



A. Suppressed sideband, single carrier



a. Amplitude modulation



B. Suppressed sideband, suppressed carrier



b. Frequency modulation



C. Single sideband, suppressed carrier



c. Phase modulation



D. Single sideband, single carrier



d. Angle modulation

247. Which process occurs in the receiver?

254. In FM radio communication system, narrow-band (NBFM)



A. Demodulation



B. Reception

is used rather than wideband (WBFM), because it, 

a. Improves signal to noise ration



C. Modulation



b. Reduces interchannel interference



D. Recreation



c. Provides maximum coverage for a given amount of

248. What is usually used to demodulate SSB or CW signal? 

A. PLL

power 

d. All of the above

255. Radio transmitter basically consists of two principal parts,



c. TV

one reproducing a carrier frequency and one for __________.



d. None of these



a. IF Frequency

262. Recovers the modulating voltage from the frequency



b. RF Frequency

modulation by utilizing the phase angle shift between primary



c. Modulating Frequency

and secondary voltages of tuned oscillators.



d. Power



a. Direct method

256. Is a measure of its ability to maintain as nearly a fixed



b. Indirect method

frequency as possible over as long as time interval as possible.



c. Foster-Seeley discriminator



d. Slope detector



a. Receiver Noise Factor



b. Selectivity

263. Is used in FM receivers to “lock onto” the received signal



c. Sensitivity

and stabilized receptions.



d. Frequency stability



a. Automatic Gain Control

257. Is the effect of two-transmitter when they are in c lose



b. Automatic Frequency Control

proximity. This results into the sum and difference frequencies



c. Muscle Control

of two carriers.



d. Automatic Frequency Gain Control



a. Intermodulation effect

264. Are amplifier circuits that are used to eliminate amplitude



b. Intermodulation interference

modulation and amplitude-modulated noise from received FM



c. Intermodulation product

Signals before detection.



d. intermodulation



a. Demodulators

258. _________ is a continuous frequency capable of being



b. Diode detector

modulated or impressed with a second information carrying



c. Amplitude limiters

signal.



d. None of these



a. Carrier frequency

265. If the total sideband power is 12.5% of the total radiated



b. Center frequency

power, find the modulation index.



c. IF frequency



a. 50 percent



d. RF frequency



b. 53.4 percent

259. The varactor diode used in FM may be represented by the



c. 26.2 percent

approximate equivalent circuit of the _____ in series with a



d. 32.3 percent

________.

266. Carriers are spaced at 20 kHz, beginning at 100 kHz.



a. Diode, capacitor

Each carrier is modulated by a signal with a 5 kHz bandwidth.



b. Diode, resistor

Is there interference from the sideband?



c. Capacitor, resistor



a. Yes



d. Any of these



b. No



c. Maybe



d. Secret

260. The name varactor comes from variable _________. 

a. Resistor



b. Capacitor

267. For an unmodulated carrier of 150 V and a modulated



c. Diode

peak value of 230 V. What is the modulation index



d. reactor



a. 0.35

261. 75 microseconds pre-emphasis time is used in



b. 0.533

__________.



c. 0.652



d. 0.42



a. FM



b. AM

268. New frequencies outside the regular AM spectrum are



a. Monophonic

called ___________.



b. Stereophonic



a. Distortion



c. Stereonic



b. Interference



d. SCA



c. Splatter

275. It make use of the shape of IF filter frequency response



d. Harmonic

roll-off versus frequency.

269. A DSB-SC has a total power of 350 watts with 100%



a. Foster Seeley

modulation suppresses 50% of the carrier, and the suppressed



b. Slope detector

carrier power goes to the sidebands. How much power is in the



c. Diode detector

sidebands?



d. Quadrature detector



a. 116.67 W

276. In AM, modulation index is a number lying between ____



b. 233.33 W

and 1.



c. 175 W



a. 2



d. 350 W



b. 5

270. A DSB-SC system must suppress the carrier by 30 dB



c. 0

from its srcinal value of 30 W. What value must the carrier be



d. 3

reduced?

277. This form of modulation is also known as independent



a. 30000 W



b. 0.03 W



a. A3E



c. 300 W



b. R3E



d. 0.003 W



c. H3E



d. B8E

271. ___________, which further amplifies the signal and has

sideband emission.

the bandwidth and passband shaping appropriate for the

278. An attenuated carrier is reinserted into the SSB signal to

received signal.

facilitate receiver tuning and demodulation.



a. RF stage



a. A3E



b. Mixer and local oscillator stage



b. R3E



c. IF stage



c. H3E



d. AF stage



d. B8E

272. In FM, a bandwidth estimate 98 percent level of Bessel functions

279. Standard AM used for broadcasting 

a. A3E



a. Approximate bandwidth



b. R3E



b. Narrow-band Bandwidth



c. H3E



c. Carson’s rule



d. B8E



d. Wideband bandwidth

273. The complete series of stages for reproducing the FM signal with the desired carrier and deviation is the _______.

280. Single sideband, suppressed carrier in which the carrie r is suppressed by at least 45 dB in the transmitter. 

a. A3E



a. Modulator



b. R3E



b. Exciter



c. H3E



c. IF stage



d. B8E



d. RF stage

281. The shift in the carrier frequency from the resting point

274. Is the ability of FM system to provide low-noise, high

compared to the amplitude of the modulating signal is called

fidelity music background/broadcast..

_______.



a. Index



b. Deviation ratio

288. If the input resistance of the base station of AM broadcast



c. Carrier frequency

produced 20 kW carrier power, at what modulation index



d. Deviation frequency

should the antenna rise at 108.63 A?



d. 4 kW

282. In FM, the amplitude of the modulated frequency wave



a. 20%

remains ___________ at all times.



b. 50%



a. Varying



c. 60%



b. Dependent



d. 80%



c. Constant

289. ________ used a phase detector to compare the phase



d. variable

and frequency of the received signal to the VCO output.

283. An AM has a maximum span of 30 V, what is the required



a. PIL

minimum span to attain 100% modulation?



b. PAL



a. 30 V



c. PLL



b. 20 V



d. PLI



c. 0 V

290. A filter with a roll-off of 6 dB/kHz is used as a s lope



d. None of these

detector. The input signal varies with +3 kHz deviation from

284. DZMM having a carrier frequency of 630 kHz is

center carrier frequency. How many dB down is the output at

modulated by 2.6 kHz audio signal having an amplitude of 37.5

full deviation?

V. What is the amplitude voltage of 630 kHz carrier frequency



a. 9 dB

at 0.35 modulation index?



b. -18 dB



a. 57.6 V



c. 18 dB



b. 107.14 V



d. -9 dB



c. 206.5 V

291. A receiver limiter requires a 20 mV signal for quieting



d. 86.2 V

operation. The voltage gain between the RF input and the

285. If the sideband power is 50% of the carrier power, what is

limiter is 57.7 dB, what is the input at the antenna terminal

the modulation index?

assuming equal resistance?



a. 50%



a. 75.6 mV



b. 75%



b. 26.67 uV



c. 90%



c. 52.3 uV



d. 100%



d. 49.6 uV

286. If the increase power is 180 watts at 1 kW unmodulated

292. A 1-MHz carrier is modulated with a resulting 100 Hz

output power the modulation index is _________.

deviation. It undergoes x36 multiplication, followed by mixing



a. 75%

with a 34.5 MHz signal and re-multiplication by 72. What is the



b. 60%

final carrier and deviations?



c. 50%



a. 5076 MHz, ± 2592 MHz



d. 25%



b. 2592 MHz, ± 259.2 kHz

287. In AM, if the unmodulated power carrier is 10 kW, and the



c. 2592MHz, ± 5076 MHz

total power is 15 kW, what is the upper sideband power at



d. 259.2 MHz, ± 108 kHz

100% modulation index?

293. For standard commercial broadcast FM, the deviation



a. 25 kW



b. 2 kW

ratio is ________. 

a. 15



c. 2.5 kW



b. 75



c. 5

300. Undesired signal on the other side of the local oscillator



d. 10

output will have the same difference frequency and pass into

294. A system has 150 kHz of bandwidth available for 10 kHz

the IF amplifier.

modulation signal. What is the approximate deviation to be



a. Carrier frequency

used?



b. Sum frequency



a. 35 kHz



c. Difference frequency



b. 65 kHz



d. Image frequency



c. 25 kHz

301. One of the following refers to an output of a balanced



d. 15 kHz

modulator

295. An FM has a deviation of 100 kHz and a modulating



a. SSB

frequency of 15 kHz, what happen to m if the deviation triples?



b. ISB



a. 6.66



c. AM



b. 2.22



d. DSB



c. 4.12

302. Which of the following components is used to produce AM



d. 0.20

at very high frequencies?

296. A receiver for a signal at 100 MHz uses a 10.7 MHz IF



a. Cavity resonator

and low tracking. What is the image frequency?



b. PIN diode



a. 89.3 MHz



c. Varactor



b. 78.6 MHz



d. Thermistor



c. 52.5 MHz

303. A third symbol emission which re present data



d. 35.2 MHz

transmission including telemetry, and telecommand

297. What is the change in resonant frequency of the actual



a. B

varactor capacitance value differs by -5% (0.05) of the nominal



b. D

value?



c. C



d. N



a. 2.06



b. 3.02



c. 1.03



a. None of these



d. 5.06



b. Sidebands

298. An oscillator resonate at 1 MHz with a nominal 100 pF



c. Both the sidebands and the carrier

capacitor and 0.25 mH inductor, what s the resonant frequency



d. Carrier

of the actual capacitor value is +20% of the nominal value?

304. In an AM wave, useful power is carried by

305. Determine the modulation index of an standard FM



a. 1.006 MHz

broadcast having a hypothetical maximum carrier frequency



b. 0.9188 MHz

deviation of ±12 kHz and a maximum modulating frequency pf



c. 3.625 MHz

4kHz.



d. 2.00123 MHz

299. “Front end” is also called _________.



a. 9



b. 6



a. IF stage



c. 3



b. AF stage



d. 4



c. RF stage

306. The process by which the intelligence signals normally at



d. None of these

lower frequency are removed from the transmission frequency after it is received in the receiver s tation. 

a. Detection



b. Demodulation



c. Amplification

313. One of the following is a communications filter generally



d. Modulation

used in the transceiver of a s ingle sideband generator.

307. What is meant by the term modulation?



d. A



a. Lowpass filter

a. The squelching of a signal until a c ritical signal-to-



b. Crystal filter

noise ratio is reached



c. Bandpass filter



b. Carrier rejection through phase nulling



d. Mechanical filter



c. A linear amplification mode

314. What is the modulation index for an AM s ignal having



d. A mixing process whereby information is imposed

Vmax and Vmin of 2.6 and 0.29, respectively?



upon a carrier 308. What is a balanced modulator?



a. 0.799



b. 0.111



a. An FM modulator that produces balance de viation



c. 0.894



b. A modulator that produces a DSBSC signal



d. 0.639



c. A modulator that produces a SSBSC signal

315. What is the bandwidth of an AM signal modulated by a



d. A modulator that produces a full carrier signal

15-kHz intelligence signal?

309. What is a reactance modulator? 









a. 7.5 kHz

a. A circuit that acts as a variable resistance or



b. 15 kHz

capacitance to produce FM signals



c. 30 kHz

b. A circuit that acts as a variable resistance or



d. 60 kHz

capacitance to produce AM signals

316. If a transmitter supplies 10 kW to the antenna when it is

c. A circuit that acts as a variable inductance or

unmodulated, determine the total radiated power when it is

capacitance to produce FM signals

modulated at 30%

d. A circuit that acts as a variable inductance or



a. 10.45 watts

capacitance to produce AM signals



b. 10750 watts



c. 11.5 kilowatts



d. 10450 watts

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

317. Which of the following waveform characteristics

mixer

determines the wavelength of a sine wave?



c. By using a loop modulator followed by a mixer



a. Phase



d. By using a balanced modulator followed by a filter



b. Amplitude



c. Period



d. Phase angle

311. How can a DSB phone signal be generated? 

a. By feeding a phase modulated signal into a low pass filter

318. In the F3E signal, what is the term for the ratio between



b. By using a balanced modulator followed by a filter

the deviation of a frequency modulated signal and the



c. By detuning a Hartley oscillator

modulating frequency?



d. By modulating the plate voltage of a class C



a. FM compressibility

amplifier



b. Quieting index

312. First symbol in the designation of radio s ignals emission



c. Modulation index

which refers to use of an unmodulated carrier.



d. Percentage of modulation



a. J

319. Which frequency band is the standard AM ra dio



b. N

broadcast?



c. H



a. HF



b. UHF

326. What is the source of sidebands in frequency modulated



c. MF

voice?



d. VHF



a. A3F

320. The letter-designation B8E is a form of modulation also



b. A3J

known as



c. F3E



d. J3E



a. Pilot carrier system



b. Independent sideband emission

327. The third symbol in the designation of radio emission



c. Lincompex

under the ITU refers to



d. Vestigial sideband transmission



a. Type of modulation of the main carrier

321. What are the two general categories of methods for



b. Nature of signals

generating emission F3E?



c. Type of information to be transmitted



d. Nature of multiplexing









a. The only way to produce an emission F3E signal is with reactance modulator on the oscillator

328. An AM transmission of 3 kW is 100% modulated. If it is

b. The only way to produce an emission F3E signal is

transmitted as an SSB signal, what would be the total power

with a balanced modulator on the oscillator

transmitted?

c. The only way to produce an emission F3E signal is



a. 500 W

with a balanced modulator on the audio amplifier



b. 1000 W

d. The only way to produce an emission F3E signal is



c. 1500 W

with a reactance modulator on the final amplifier



d. 2000 W

322. 100% modulation in AM means a corresponding increase

329. This circuit has the function of demodulating the

in total power by ____.

frequency-modulated signal. It is a



a. 25%



a. Automatic gain control



b. 75%



b. Automatic frequency control



c. 100%



c. Envelope detector



d. 50%



d. Foster-Seeley discriminator

323. How does the SSB transmitter output power normally

330. Calculate the power in one sideband of an AM signal

expressed?

whose carrier power is 50 watts. The unmodulated current is 2



a. Average power



b. In terms of peak envelope power



a. 22 W



c. In terms of peak-to-peak power



b. 33 W



d. Peak power



c. 11 W



d. 44 W

324. Determine from the following the common use of DSB in broadcast and telecommunications

A while the modulated current is 2.4 A.

331. The method of generating FM used by broadcasting



a. Satellite communication



b. FM/TV stereo



a. Direct



c. Two-way communications



b. All of these



d. Telephone systems



c. Indirect



d. Insertion

325. What is the source of sidebands in frequency modulation? 

a. Oscillator



b. Baseband frequency



c. Mixer



d. Carrier harmonics

station is

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

is 85% modulated by a 3 MHz sine wave. Calculate the RMS



d. Highest modulating frequency to the minimum

voltage of the signal.

frequency



a. 825 W

333. An AM transmitter is modulated by two sine waves at 1.5



b. 262. 61 V

kHz and 2.5 kHz with modulations of 20 percent and 80



c. 1166.7 V

percent respectively. Calculate the effective modulation index.



d. 825 V



a. 0.7776

340. What will be the total sideband power of the AM



b. 0.6

transmitting station whose carrier power is 1200W and a



c. 0.8246

modulation of 95%?



d. 1.0



a. 270.75 W

334. A DSBSC system must suppress the carrier by 50 dB for



b. 900 watts

its srcinal value of 10 W. To what value must the carrier be



c. 1.8 kW

reduced?



d. 542 W



a. 1 milliwatt

341. Which among the following is capable of generating



b. 10 microwatts

frequency conversion?



c. 0.10 milliwatts



a. Balanced modulator



d. 0.01 microwatts



b. Low-Q LC Circuit

335. Which circuit in the AM transmitter does the frequency



c. Transmitter

translation?



d. Circulator



a. Synthesizer



b. Modulator



a. Envelope detector



c. Mixer



b. PLL



d. Booster



c. Mixer



d. Balanced modulator

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?

342. The most commonly used AM demodulator

343. Which is a disadvantage of direct FM generation? 

a. The need for an AFC c ircuit



a. 0.158 V



b. The need for an AGC circuit



b. 0.185 V



c. Two balanced modulators are used



c. 0.518 V



d. The use of Class A amplifier which is very



d. 0.815 V

337. In a phase-locked loop, VCO stands for

inefficient 344. Frequency division is useful in the implementation of a/an



a. Variable capacitor oscillator



a. AM demodulator



b. Varactor-capacitor oscillator



b. Frequency synthesizer



c. Voltage-controlled oscillator



c. AGC circuit



d. VHF control oscillator



d. FM demodulator

338. Diagonal clipping in envelope detection will result in

345. A particular synthesizer which contains only a s ingle



a. Distortion



b. Diagonal clipping



a. Direct



c. Phase reversal



b. Crystal-modulated



d. Amplitude damage



c. Indirect



d. Exact

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

crystal is

346. Type of emission most affected by selective fading



a. FM and DSB AM



b. Approximately equal to X L



b. SSB and TV



c. Low, as compared to the c ircuit resistance



c. CCTV and CW



d. Approximately equal to X C



d. CW and SSB

347. Which major element will not be found in every superheterodyne receiver?

354. What are the three major oscillator circuits often used in radio equipment? 

a. Taft, Pierce, and negative feedback



a. RF amplifier



b. Colpitts, Hartley, and Taft



b. IF amplifier



c. Taft, Hartley, and Pierce



c. LO



d. Colpitts, Hartley, and Pierce



d. Mixer

348. A system uses a deviation of 100 kHz and a modulating frequency of 15 kHz. What is the approximate bandwidth?

355. How is a positive feedback coupled to the input in a Hartley oscillator? 

a. Through a neutralizing capacitor



a. 115 kHz



b. Through a capacitive divider



b. 230 kHz



c. Through a link coupling



c. 170 kHz



d. Through a tapped coil



d. 340 kHz

349. A quadrature detector requires that

356. How is the positive feedback coupled to the input in a Colpitts oscillator?



a. The inputs are coherent



a. Through a tapped coil



b. Four gates are provided



b. Trough link coupling



c. The inputs are in phase



c. Through a capacitive divider



d. The inputs are similar



d. Through a neutralizing capacitor

350. What is the power in one sideband of an AM signal whose

357. How is a positive feedback coupled to the input in a

carrier power is 300 W, with 80 percent modulation?

Pierce oscillator?



a. 396 W



a. Through a tapped coil



b. Zero



b. Trough link coupling



c. 48 W



c. Through a capacitive divider



d. 96 W



d. Through a neutralizing capacitor

351. Determine the resonant frequency of a series combination

358. Which of the three major oscillator circuits used in radio

of a 0.001 microfarad capacitor and a 2 – milihenry inductor.

equipment utilizes a quartz crystal?



a. 112.5 kHz



a. Negative feedback



b. 35.59 kHz



b. Hartley



c. 1125.4 MHz



c. Colpitts



d. 3.26 MHz



d. Pierce

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

359. What is the piezoelectric effect? 

of a voltage 



a. Approximately equal to the circuit resistance

b. Mechanical deformation of a crystal by the application of a magnetic field



353. What is the approximate magnitude of the impedance of a parallel RLC circuit at resonance?

a. Mechanical vibration of a crystal by the application

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?



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



a. Pierce



b. By tuning for maximum power output



b. Colpitts



c. By neutralization



c. Hartley



d. By tuning the output



d. Negative feedback

362. Why is the Colpitts oscillator circuit commonly used in a VFO?

368. If the spectrum is shifted in frequency with no other changes, this is known as 

a. Frequency multiplication

a. The frequency is a linear function of the load



b. Sideband movement

impedance



c. Baseband orientation



b. It can be used with or without crystal lock-in



d. Frequency translation



c. It is stable

369. A device which is capable of causing frequency



d. It has high output power

translation



363. How is the efficiency of a power amplifier determined?



a. High-Q tank circuit



a. Efficiency = (RF power out / dc power in) x 100%



b. Balanced modulator



b. Efficiency = (RF power in / RF power out) x 100%



c. Low-Q tank circuit



c. Efficiency = (RF power in / dc power in) x 100%



d. IF strip



d. Efficiency = (dc power in / RF power in) x 100%

364. For reasonably efficient operation of a transistor amplifier,

370. If the frequency of each component in a signal spectrum is increased by the same fixed amount, this is known as

what should be the load resistance be with 12 volts at the



a. Up conversion

collector and a 5 watts power output?



b. Demodulation



a. 100.3 ohms



c. Frequency translation



b. 14.4 ohms



d. Both a and c



c. 10.3 ohms

371. A particular amplifier is designed to be a frequency



d. 144 ohms

doubler. If the input signal frequency is 15.4 MHz, a circ uit in

365. What order of Q is required by a tank circuit sufficient to reduce harmonics to an acceptable level?

the output will be tuned to 

a. 7.7 MHz



a. Approximately 120



b. 15.4 MHz



b. Approximately 12



c. 30.8 MHz



c. Approximately 1200



d. 61.6 MHz



d. Approximately 1.2

366. What is the flywheel effect? 



372. Any device to be used as a frequency multiplier must be 

a. Active

a. The continued motion of a radio wave through



b. Passive

space when the transmitter is turned off



c. Linear

b. The back and forth oscillation of electrons in a n LC



d. Nonlinear

circuit

373. A particular amplifier circuit used for frequency coupling is known as



a. Push-push



c. Loudness controller



b. Push-pull



d. All of the above



c. Pull-push

381. Class C amplifiers are not used in which type of



d. Pull-pull

transmitter?

374. Frequency division is useful in the implementation of a



a. AM



a. AM demodulation



b. SSB



b. Frequency synthesizer



c. CW



c. FM demodulator



d. FM



d. AGC circuit

375. Indirect frequency synthesizers will include

382. A circuit that isolates the carrier oscillator from load changes is called a



a. phase-locked loop



a. Final amplifier



b. voltage-controlled oscillators



b. Driver amplifier



c. multiple bank crystals



c. Linear amplifier



d. both A and B



d. Buffer amplifier

376. A particular frequency synthesizer contains only a s ingle

383. Bias for class c amplifier produced by an input RC

crystal. What words describe this synthesizer?

network is known as



a. Crystal modulated



a. Signal bias



b. Inexact



b. Self-bias



c. Indirect



c. Fixed external bias



d. Deficient



d. Threshold bias

377. A recognizable feature of a CW transmitter is

384. Collector current in a class C amplifier is



a. Keyed transmitter



a. Sine wave



b. Power amplification



b. Half-sine wave



c. Frequency generation



c. Pulse



d. All of the above



d. Square wave

378. The term “pulling” refers to

385. Neutralizing is the process of

a. The change of the crystal osc illator frequency by



a. Cancelling the effect of internal device capacitance

loading



b. Bypassing undesired alternating current



b. One-half cycle operation of a push-pull amplifier



c. Reducing gain



c. Loading on the transmitter caused by the antenna



d. Eliminating harmonics



connection

386. In an AM transmitter, a clipper circuit eliminates

d. Reduction of the power supply terminal voltage as



a. Harmonics

the transmitter is keyed



b. Splatter

379. An AM broadcast transmitter in the multi-kilowatt



c. Over-deviation

operating range will have what form of final amplifier?



d. Excessive gain





a. Solid-state devices

387. The final power amplifier in an FM transmitter usually



b. Vacuum tubes

operates class



c. Travelling wave tubes



a. A



d. Both a and b



b. B



c. C



d. D

380. In a broadcast station, the AGC is referred to as 

a. Automatic gain control limiter



b. Compression amplifier

388. A transistor RF power amplifier can be tuned for



a. Minimum I C in the next stage

a doubler is 198 MHz, what frequency s hould the oscillator



b. Zero signal in the next stage

operate?



c. Minimum I C in the same stage



a. 11 MHz



d. Maximum I C in the same stage



b. 33 MHz

389. The purpose of a balanced modulator circuit is to



c. 22 MHz

eliminate the



d. 66 MHz



a. Carrier

395. A phase-locked loop has a VCO with a free running



b. Upper sideband

frequency of 14 MHz. As the frequency of the reference input



c. Lower sideband

is gradually raised from zero, the loop locks at 12 MHZ and



d. Baseband signal

comes out of lock again at 18 MHz. Calculate the lock range.

390. A frequency multiplier circuit



a. 4 MHz



a. Operates class A



b. 2 MHz



b. Is tuned to a harmonic of the input signal



c. 12 MHz



c. Needs parasitic oscillations



d. 8 MHz



d. Is usually pulse modulated

391. An IF transformer of a radio receiver operates at 456 kHz.

396. A crystal oscillator is accurate within 0.0005%. How f ar off frequency could its output be at 37 MHz?

The primary circuit has a Q of 50 and the secondary has a Q of



a. 135 Hz

40. Find the bandwidth using the optimum coupling factor.



b. 150 Hz



a. 10.192 kHz



c. 185 Hz



b. 15.288 kHz



d. 224 Hz



c. 152.88 kHz

397. A transmitter has a carrier power output of 10 W at an



d. 101.92 kHz

efficiency of 80%. How much power must be supplied by the

392. A varactor has a maximum capacitance of 80pF and is

modulating amplifier for 100% modulation?

used in a tuned circuit with a 100 microhenry inductor. Find the



a. 6.25 W

tuning voltage necessary for the circuit to resonate at twice its



b. 7.14 W

resonant frequency with no tuning voltage applied.



c. 12.5 W



d. 14.3 W



a. 5 V



b. 2.5 V

398. A transmitter operates from a 16 V supply, with a collector



c. 7.5 V

current of 2 A. The modulation transformer has a turns ratio of



d. 4.25 V

4:1. What is the load impedance seen by the audio amplifier?

393. A phase-locked loop has a VCO with a free-running



a. 96 ohms

frequency of 14 MHz. As the frequency of the reference input



b. 128 ohms

is gradually raised from zero, the loop locks at 12 MHz and



c. 6 ohms

comes out of lock again at 18 MHz. Calculate the capture



d. 8 ohms

range.

399. A collector-modulated class C amplifier has a carrier



a. 4 MHz

output power of 150 W and an efficiency of 80%. Calculate the



b. 2 MHz

transistor power dissipation with 100% modulation.



c. 12 MHz



a. 93. 75 W



d. 8 MHz



b. 120 W

394. If the frequency fed to the pre-amplifier of a basic



c. 64 W

transmitter with multipliers is composed of a pair of triplers and



d. 56. 25 W

400. An AM transmitter is required to produce 20 W of carrier

406. What is the term used to refer to the condition where the

power when operating from a 25 V supply. What is the required

signals from a very strong station are super imposed on the

load impedance as seen from the collector?

other signals being received?



a. 15.625 ohms



a. Intermodulation distortion



b. 22.5 ohms



b. Cross-modulation interference



c. 11.25 ohms



c. Receiver quieting



d. 31.25 ohms



d. Capture effect

401. What is receiver desensitizing?

407. How can cross-modulation in a receiver be reduced?



a. A burst of noise when the squelch is set to low



a. By installing a filter at the receiver



b. A burst of noise when the squelch is set to high



b. By using a better antenna



c. A reduction in receiver sensitivity because of a



c. By increasing the receiver’s RF gain while

strong signal on a nearby frequency 

d. A reduction in receiver s ensitivity is turned down

402. What is the term used to refer to the reduction of receiver

decreasing the AF gain 

d. By adjusting the passband tuning

408. What is the result of cross-modulation?

gain caused by the signals of a nearby station transmitting in



a. Decrease in modulation level of transmitted signals

the same frequency band?



b. Receiver quieting



c. The modulation of an unwanted signal is heard on



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 rec eiver

the desired signal 



sensitivity caused by unwanted high-level adjacent channel signals? a. Intermodulation distortion



b. Quieting



c. Desensitizing



d. Overloading

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? 



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



a. Interference between two transmitters of different modulation types

b. All signals on a frequency are demodulated by an AM receiver



404. How can receiver desensitizing be reduced? 

a. All signals on a frequency are demodulated by an FM receiver





d. Inverted sidebands in the final stage of the amplifier

409. What is the capture effect?

c. A detector that uses mixing proc ess with a locally generated carrier



b. Interference caused by audio rectification in the

d. A detector used to detect cross -modulation products

receiver preamp

411. What is the term used to refer to the reception blockage of



c. Decrease the receiver squelch gain

one FM-phone signal?



d. Modulation from an unwanted signal is heard in



a. Desensitization

addition to the desired signal



b. Cross-modulation interference



c. Capture effect



d. Frequency discrimination

412. What is the process of detection? 



418. What occurs in a receiver when an excessive amount of signal energy reaches the mixer circuit?

a. The process of masking out the intelligence on a



a. Spurious mixer products are generated

received carrier to make an S-meter operational



b. Mixer blanking occurs

b. The recovery of intelligence from the modulated RF



c. Automatic limiting occurs

signal



d. A beat frequency is generated



c. The modulation of a carrier

419. How much gain should be used in the RF amplifier stage



d. The mixing of noise with the received signal

of a receiver?

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



a. As much as possible short of self oscillation



b. Sufficient gain to allow weak signals to overcome noise generated in the first mixer



diode 

d. The change of reactance in the diode with respect

noise of the first mixer stage 

to frequency 414. How are FM phone signals detected?

c. Sufficient gain to keep weak signals below the

d. It depends on the amplification factor of the first IF stage

420. Why should the RF amplifier stage of a receiver only have



a. By a balanced modulator

sufficient gain to allow weak signals to overcome noise



b. By a frequency discriminator

generated in the first mixer stage?



c. By a product detector



d. By a phase s plitter

415. What is the mixing process? 





a. To prevent the sum and difference frequencies from being generated



b. To prevent bleed-through of the desired signal

a. The elimination of noise in a wideband receiver by



c. To prevent generation of spurious mixer products

phase comparison



d. To prevent bleed-trough of the local oscillator

b. The elimination of noise in a wideband receiver by

421. What is the primary purpose of an RF amplifier in a

phase differentiation

receiver?



c. Distortion caused by aural propagation



a. To provide most of the receiver gain



d. The combination of the two signals to produce s um



b. To vary the receiver image rejection by utilizing the

and difference frequencies 416. What is a frequency discriminator?

AGC 

c. To improve the receiver’s noise figure



d. To develop the AGC voltage



a. A circuit for detecting FM signals



b. A circuit for filtering two closely adjacent signals



c. An automatic band switching circuit



a. A fixed-tuned passband amplifier



d. An FM generator



b. A receiver demodulator

417. What are the principal frequencies which appear at the



c. A receiver filter

output of a mixer circuit?



d. A buffer oscillator

422. What is an IF amplifier stage?



a. Two and four times the srcinal frequency

423. What factors should be considered when selecting an



b. The sum, difference and square root of the input

intermediate frequency?





frequencies



a. A cross-modulation distortion and interference

c. The srcinal frequencies and the sum and



b. Interference to other services

difference frequencies



c. Image rejection and selectivity

d. 1.414 and 0.707 times the frequency



d. Noise figure and distortion

424. What is the primary purpose of the first IF amplifier stage



in a receiver?

c. Cross-modulation of the desired signal and insufficient audio power to operate the speaker



a. A noise figure performance



b. Tune out cross-modulation distortion



c. Dynamic response

430. What is the term for the ratio between the largest tolerable



d. Selectivity

receiver input signal and the minimum discernible signal?



d. Oscillator instability and severe audio distortion of all but the strongest signal received signals

425. What is the primary purpose of the final IF amplifier stage



a. Intermodulation distortion

in a receiver?



b. Noise floor



a. Dynamic response



c. Noise figure



b. Gain



d. Dynamic range



c. Noise figure performance

431. What occurs during CW reception if too narrow a filter



d. Bypass undesired signals

bandwidth is used in the IF stage of a receiver?

426. Which stage of a receiver primarily establishes its noise



a. Undesired signals will reach the audio s tage

figure?



b. Output-offset overshoot



a. The audio stage



c. Cross-modulation distortion



b. The IF stage



d. Filter ringing



c. The RF stage

432. How can selectivity be achieved in the front and circuitry



d. The local oscillator

of a communications receiver?

427. What is meant by the term noise figure in a



a. By using an audio filter

communications receiver?



b. By using a pre-selector

a. The level of noise entering the receiver from the



c. By using an additional RF amplifier stage

antenna



d. By using an additional IF amplifier stage







b. The relative strength of a strength of a re ceived

433. How should the filter bandwidth of a receiver IF section

signal 3 kHz removed from the carrier frequency

compare with the bandwidth of a received signal?

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

received signal bandwidth 

at frequencies close to the desired one 428. The ability of a communications receiver to perform well in

b. Filter bandwidth should be approximately half the received signal bandwidth



the presence of strong signals outside the band of interest is indicated by what parameter?

a. Filter bandwidth should be slightly greater than the

c. Filter bandwidth should be approximately two times the received signal bandwidth



d. Filter bandwidth should be approximately four times



a. Noise figure



b. Blocking dynamic range

434. How can receiver selectivity be achieved in the IF circuitry

the received signal bandwidth



c. Signal-to-noise ratio

of a communications receiver?



d. Audio output



429. What type problems are caused by poor dynamic range in a communications receiver? 



to the local oscillator circuitry 

a. Cross-modulation of the desired signal and desensitization from strong adjacent signals

should it be transmitted

b. Replace the standard JFET mixer with a bipolar transistor followed by a capacitor of the proper value



b. Oscillator instability requiring frequent returning, and loss of ability to recover the opposite sideband

a. Incorporate a means of varying the supply voltage

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

441. What parameter must be selected when designing an

blocking dynamic range of 60 dB. W hat is the strongest signal

audio filter using an op-amp?

that can be present along with a 0.6 microvolt signal without



a. Bandwidth characteristics

blocking taking place



b. Desired current gain



a. 600 millivolts



c. Temperature coefficient



b. 600 microvolts



d. Output-offset overshoot



c. 300 millivolts



d. 300 mircovolts

442. What two factors determine the sensitivity of a receiver? 

a. Dynamic range and third-order intercept

436. An AM receiver is tuned to broadcast station at 600 kHz.



b. Cost and availability

Calculate the image rejection in dB assuming that the input



c. Intermodulation distortion and dynamic range

filter consists of one tuned circuit with a Q of 40?



d. Bandwidth and noise figure



a. 19.28 dB

443. How can unwanted ringing and audio instability be



b. 39.65 dB

prevented in a multi-section op-amp RC audio filter circuit?



c. 38.57 dB



a. Restrict both gain and Q



d. 19.83 dB



b. Restrict gain, but increase Q

437. A receiver has two uncoupled tuned circuits before the



c. Restrict Q but increase gain

mixer, each with a Q of 75. The signal frequency is 100.1 MHz.



d. Increase both gain and Q

The IF is 10.7 Mhz. The local oscillator uses high-side

444. What is meant by the dynamic range of a communications

injection. Calculate the image rejection ratio.

receiver?



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



highest frequency to which the receiver can be tuned 

a. 2.954 MHz



b. 4.832 MHz



c. 4.210 MHz



d. 2.328 MHz

b. The maximum possible undistorted audio output of the receiver referenced to one milliwatt



kHz up to 3.58 MHz? 

a. The number of kHz between the lowest and the

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 dete rmines the signal-

439. What is the undesirable effect of using too wide a filter

to-noise ratio in a VHF (150 MHz) marine band receiver

bandwidth in the IF section of a receiver?

generated?



a. Output-offset overshoot



a. In the receiver front end



b. Undesired signals will reach the audio s tage



b. Man-made noise



c. Thermal noise distortion



c. In the atmosphere



d. Filter ringing



d. In the ionosphere

440. What is the limiting condition for sensitivity in a

446. An AM receiver uses a diode detector for demodulation.

communications receiver?

This enables it satisfactorily to receive



a. the noise floor of the receiver



a. Single-sideband, suppressed carrier (J3E)



b. the power supply output ripple



b. Single-sideband, reduced carrier (R3E)



c. the two-tone intermodulation distorting



c. ISB(B8E)



d. the input impedance to the detector



d. Single-sideband, full carrier (H3E)

447. Three-point tracking is achieved with



a. Variable selectivity

454. It is the process of changing the amplitude of a relative



b. The padder capacitor

high frequency carrier signal in proportion with the



c. Double spotting

instantaneous value of the modulating signal.



d. Double conversion



a. frequency modulation

448. A receiver has poor IF selectivity. It will therefore also



b. digital modulation

have poor



c. phase modulation



d. analog modulation



a. Blocking



b. Double-spotting



c. Diversity reception



a. carrier



d. Sensitivity



b. upper sideband

449. If a FET is used as the first AF amplifier in a transistor



c. lower sideband

receiver, this will have the effect of



d. modulating signal

455. Most of the power in an AM signal is in the



a. Gain variation over the frequency coverage range



b. Insufficient gain and selectivity



a. linear mixing



c. Inadequate selectivity at high frequencies



b. analog multiplexing



d. Instability



c. signal summation



d. multiplexing

450. The image frequency of a superheterodyne receiver

456. Amplitude modulation is the same as



a. Is created within the receiver itself

457. The shape of the amplitude-modulated wave is called



b. Is due to insufficient adjacent channel rejection

______.



c. Is not rejected by the IF tuned circuits



a. sidebands



d. Is independent of the frequency to which receiver is



b. modulating signal

tuned



c. envelope



d. carrier signal

451. The process of impressing a low frequency information signals onto a high-frequency carrier signal is called _____.

458. In a diode modulator, the negative half of the AM wave is



a. demodulation



b. oscillation



a. tuned circuit



c. modulation



b. transformer



d. amplification



c. capacitor



d. inductor

452. A silicon varactor diode exhibits a c apacitance of 200pF

supplied by

at zero bias. If it is in parallel with a 60-pF capacitor and a 200-

459. It is a term used to describe the amount of amplitude

uH inductor, calculate the range of resonant frequency as the

change present in an AM waveform.

diode varies through a reverse bias of 3 to 15V.



a. coefficient of modulation



a. 679 kHz to 2.13 MHz



b. modulation index



b. 966 kHz to 1.15 MHz



c. depth of modulation



c. 355 kHz to 3.12 MHz



d. any of these



d. 143 kHz to 4.53 MHz

453. A process where the received s ignal is transformed into its srcinal form.

460. When the modulation index in an AM wave is greater than one it will cause _______. 

a. buck-shot



a. demodulation



b. splatter



b. damping



c. overmodulation



c. amplification



d. any of these



d. oscillation

461. The ideal value of modulation index in AM.



a. 1



c. low-level modulation



b. 0



d. high-level modulation



c. 100

468. If a superheterodyne receiver is tuned to a desired signal



d. infinity

at 1000kHz and its conversion (local) oscillator is operating at

462. When the amplitude of the information in an AM

1300kHz, what would be the frequency of an incoming signal

modulator is equal to zero, what is the value of the modulation

that would possibly cause image reception?

index?



a. 1600 kHz



a. 1



b. 2300 kHz



b. 0



c. 1250 kHz



c. 100



d. 3420 kHz



d. infinity

463. Amplitude modulation can be produced by

469. When modulation requires a much higher amplitude modulating signal to achieve a reasonable percent modulation,



a. having the carrier vary a resistance



b. having the modulating signal vary a c apacitance



a. high-level modulation



c. varying the carrier frequency



b. low-level modulation



d. varying the gain of the amplifier



c. zero-modulation



d. constant modulation

464. When the modulation index is equal to zero, the total transmitted power is equal to ________.

this is called

470. Amplitude modulators that vary the carrier amplitude with



a. one of the sidebands

the modulating signal by passing it through an attenuator work



b. carrier

on principle of



c. double sidebands



a. rectification



d. an AM wave



b. resonance

465. When the modulation takes place prior to the output



c. variable resistance

element of the final stage of the transmitter, prior to the



d. absorption

collector of the output transistor in a transistorized transmitter,

471. A circuit which function is to raise the amplitude of the

this is called ______.

source signal to a usable level while producing minimum



a. high-level modulation



b. low-level modulation



a. power amplifier



c. zero-modulation



b. non-linear amplifier



d. constant modulation



c. buffer amplifier



d. preamplifier

466. A circuit that monitors the received signal level and sends

nonlinear distortion adding as little thermal noise as possible.

a signal back to the RF and IF amplifiers to adjust their gain

472. A circuit that has a low-gain, high-input impedance linear

automatically.

amplifier which is used to isolate the oscillator from the high-



a. automatic phase control



b. automatic gain control



a. power amplifier



c. automatic frequency control



b. bandpass filter



d. automatic volume control



c. signal driver



d. buffer amplifier

467. When the modulation takes place in the final element of

power amplifiers.

the final stage where the carrier signal is a t its maximum

473. With high-level transmitters, which of the following is not a

amplitude, it is called _____.

primary function of the modulator circuit?



a. constant modulation



b. zero-modulation



a. it provides the capacity necessary for modulation to occur



b. it serves as a final amplifier

480. A receiver has a dynamic range of 81 dB. It has 0.55nW



c. it serves as a frequency up-converter

sensitivity. Determine the maximum allowable input signal.



d. it serves as a mixer



a. 59 mW

474. It is a form of amplitude distortion introduced when



b. 69 mW

positive and negative alternations in the AM modulated signal



c. 79 mW

are not equal.



d. 88 mW



a. phase shift

481. The information sources modulate the same carrier after it



b. carrier shift

has been separated into two carrier signals are at 90 degrees



c. amplitude variations

out of phase with each other.



d. frequency shift



a. QPSK

475. A carrier is simultaneously modulated by two sine waves



b. QUAM

with modulation indices of 0.3 and 0.4, the total modulation



c. PSK

index



d. FSK



a. is 1

482. Demodulating quadrature AM signal requires a carrier



b. cannot be calculated unless the phase relations are

recovery circuit to reproduce the srcinal carrier frequency and

known

phase and two balanced modulators to actually demodulate



c. is 0.5

the signals. This is called ________.



d. is 0.7



a. asynchronous detection

476. The component used to produce AM AT very high



b. quadrature demodulation

frequencies is a



c. synchronous detection



d. quadrature detection



a. varactor



b. thermistor

483. Quadrature amplitude modulation is also known as



c. cavity resonator

________.



d. PIN diode

477. It is also known as upward modulation



a. phase division multiplexing



b. phase division modulation



a. carrier shift



c. phase amplitude multiplexing



b. amplitude variations



d. phase angle modulation



c. frequency shift

484. Amplitude modulation generated at a very low voltage or



d. phase shift

power amplitude is known as

478. Also known as downward modulation



a. high-level modulation



a. carrier shift



b. low-level modulation



b. amplitude variations



c. collector modulation



c. frequency shift



d. minimum modulation



d. phase shift

479. It is a form of amplitude modulation where signals from

485. It is the first stage of the receiver and is therefore often called the receiver front end.

two separate information sources modulate the same carrier



a. mixer

frequency at the same time without interfering with each other.



b. RF section



a. QPSK



c. local oscillator



b. QUAM



d. IF stage



c. PSK



d. FSK

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



b. m = 1



d. class A RF output amplifier



c. m < 1



d. m > 1

487. The section of the receiver than down-c onverts the received RF frequencies to intermediate frequencies.

494. Why are limiters used in FM receivers?



a. RF section



a. provide better noise performance



b. local oscillator



b. clip noise peaks



c. power amplifier



c. prevent overdrive of discriminators



d. mixer



d. any of these

488. The circuit that demodulates the AM wave and converts it to the srcinal information signal.

495. Why are limiters used in FM transmitters? 

a. clip noise peaks



a. power amplifier



b. prevent overdrive of discriminators



b. local oscillator



c. prevent overdeviation



c. detector



d. any of these



d. IF section

496. It is defined as the difference in decibels between the

489. A collector modulator has a supply voltage of 48 V. The

minimum input level necessary to discern the s ignal and the

peak-to-peak amplitude of the modulating signal for 100

input level that will overdrive the receiver and produce

percent modulation is

distortion.



a. 24 V



a. dynamic range



b. 48 V



b. noise figure



c. 96 V



c. bandwidth efficiency



d. 120 V



d. bandwidth improvement

490. What signals might feed into an FM broadc ast station

497. It is the input power range over which the receiver is

audio control console?

useful.



a. microphones



a. dynamic range



b. turntables



b. noise figure



c. remote lines



c. bandwidth efficiency



d. any of these



d. bandwidth improvement

491. The noise reduction ratio achieved by reducing the

498. It is defined as the output power when the RF amplifier

bandwidth is called

response is 1-dB less than the ideal linear gain response.



a. dynamic range



a. 1-dB compression point



b. noise figure



b. 1-dB threshold point



c. bandwidth efficiency



c. 1-dB shoot-off point



d. bandwidth improvement



d. 1-dB pinch-off point

492. It is the minimum RF signal level that can be detected at

499. It is the measure of the ability of a communications

the input to the receiver and still produce a usable

system to produce, at the output of the receiver, an exact

demodulated information signal.

replica of the srcinal source information.



a. selectivity



a. sensitivity



b. sensitivity



b. threshold



c. Q-factor



c. selectivity



d. bandwidth



d. fidelity

493. For ideal AM, which of the following is true 

a. m = 0

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