1. ______ is the maximum sideband suppression value

using filter system.

A. 50 dB

B. 60 dB

C. 40 dB

D. 30 dB

2. _______ determines the number of sideband

components in FM.

A. carrier frequency

B. modulation frequency

C. modulation index

D. deviation ratio

3. One of the following transmits only one sideband.

A. H3E

B. R3E

C. A3E

D. B8E

4. What produces the sidebands on FM?

A. signal amplitude

B. carrier harmonics

C. baseband frequency

D. broadband frequency

5. Which test instrument displays the carrier and the

sidebands amplitude with frequency to frequency?

A. oscilloscope

B. spectrum analyzer

C. frequency analyzer

D. amplitude analyzer

6. Mixer is also known as a ________.

A. modulator

B. suppressor

C. converter

D. beater

7. Which one of the following emission transmits the lower

sideband and half of the upper sideband?

A. A5C

B. J3E

C. A3J

D. A3H

8. An FM receives signal ______.

A. vary in amplitude with modulation

B. vary in frequency with modulation

C. vary in frequency and amplitude with wideband

modulation

D. is not immune to noise

9. The process of impressing intelligence on the carrier is

called

A. modulation

B. detection

C. mixing

D. impression

10. ______ is an electronic instrument used to show both

the carrier and the sidebands of a modulated signal in the

frequency domain.

A. spectrum analyzer

B. oscilloscope

C. digital counter

D. frequency counter

11. What part of the carrier is varied by the intelligence

during modulation in an AM system?

A. phase

B. frequency

C. amplitude

D. both a and c

12. The difference between the RF carrier and the

modulating signal frequencies is called the

A. USB

B. LSB

C. Sideband

D. Carrier frequency

13. What stage in a radio transmitter isolates the oscillator

from the load?

A. Oscillator

B. Buffer

C. Separator

D. Mixer

14. The frequency of the unmodulated carrier in FM system

is

A. modulating frequency

B. center frequency

C. carrier frequency

D. deviation frequency

15. The ratio of maximum deviation to the maximum

modulating frequency is called

A. carrier swing

B. deviation ratio

C. modulation factor

D. modulation index

16. A carrier signal has

A. constant amplitude

B. a frequency of 20 kHz and above

C. a varying amplitude

D. the information content

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

unmodulated carrier value is 85 V. What is the modulation

index?

A. 0.47

B. 0.68

C. 0.32

D. 1.47

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

modulated by a 4.5 kHz audio signal having an amplitude of

45 V. The modulation factor is

A. 0.56

B. 0.65

C. 1.78

D. 1.25

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

carrier swing of 75 kHz when the modulating signal has

frequency of 3 kHz?

A. 25

B. 12.5

C. 0.04

D. 0.08

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

having the modulating frequency, what will be the effect on

the maximum deviation?

A. No effect

B. Maximum deviation doubles

C. Decreases by ½

D. Increases by ¼

21. Which of the following is considered as an indirect

method of generating FM?

A. Reactance modulator

B. Balanced modulator

C. Varactor diode modulator

D. Armstrong system

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

circuit known as

A. filter modulator

B. ring modulator

C. balanced modulator

D. reactance modulator

23. Which is the first radio receiver?

A. TRF receiver

B. Superheterodyne receiver

C. Crystal radio receiver

D. Heterodyne receiver

24. An interfering signal with a frequency equal to the

received signal plus twice the IF is called

A. image frequency

B. center frequency

C. rest frequency

D. interference frequency

25. Double sideband full carrier emission type

A. A3J

B. H3E

C. R3A

D. A3E

26. Single sideband reduced carrier emission type

A. H3E

B. R3E

C. J3E

D. B8E

27. A single sideband suppressed carrier emission type.

A. H3E

B. R3E

C. J3E

D. B8E

28. Independent sideband emission type

A. H3E

B. R3E

C. J3E

D. B8E

29. Vestigial sideband emission type

A. C3F

B. J3E

C. R3E

D. B8E

30. Single sideband full carrier emission type.

A. R3E

B. H3E

C. J3E

D. B8E

31. Phase modulation emission type.

A. F3E

B. F3C

C. F3F

D. G3E

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

A. Power saving

B. Requires half the bandwidth

C. Wider area of reception

D. Better fidelity

33. The advantage of a high level modulated AM transmitter

is

A. Less audio power required

B. Better fidelity

C. Higher value of operating power

D. Less distortion

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

is

A. Less audio power required

B. Better fidelity

C. Higher value of operating power

D. Less distortion

35. _____ is the bad effect caused by overmodulation in

AM transmission.

A. Increase in noise

B. Deviation in the operating frequency

C. Interface to other radio services

D. Decrease in the output power

36. Which characteristic of a radio receiver refers to its

ability to reject an unwanted signal?

A. Sensitivity

B. Selectivity

C. Fidelity

D. Quality

37. What type of emission is frequency modulation?

A. F3E

B. G3E

C. A3E

D. B3E

38. AM transmission power increases with ________.

A. Frequency

B. Source

C. Load

D. Modulation

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

A. Hall effect

B. Capture effect

C. Image frequency

D. Homing

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

A. 50 %

B. 75 %

C. 100 %

D. 80 %

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

equal to twice the sum of the modulating frequency and

______.

A. Carrier signal

B. Modulating signal

C. Frequency deviation

D. Image frequency

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

modified by 75%?

A. 53.2 kHz

B. 48 kHz

C. 56.25 kHz

D. 112.5 kHz

43. The modulation system inherently more resistant to

noise

A. Single sideband suppressed carrier

B. Frequency modulation

C. Pulse-position modulation

D. Amplitude shift keying

44. Subcarriers that are arranged so that the channels

occupying adjacent frequency bands with some frequency

space between them is known as

A. Guard bands

B. AM bands

C. Band gap

D. Void band

45. Modulation of an RF amplifier carrier results in

A. Multiple channels

B. Smaller antennas

C. Directional propagation

D. All of the above

46. A process which occurs in the transmitter

A. Mixing

B. Modulation

C. Heterodyning

D. Demodulation

47. A process which occurs in the receiver

A. Beating

B. Modulation

C. Mixing

D. Demodulation

48. One part of the transmitter that protects the crystal

oscillator from “pulling”.

A. Buffer amplifier

B. Modulator

C. Power amplifier

D. Antenna coupler

49. What aspect of the carrier is changed by modulation?

A. Frequency

B. Phase

C. Amplitude

D. Depends on the type of modulation

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

musical program will

A. Be complex

B. Contain fundamental frequencies

C. Contain harmonic frequencies

D. All of the above

ANSWER

1. 50 dB

2. modulation index

3. H3E

4. baseband frequency

5. spectrum analyzer

6. converter

7. A3H

8. Vary in frequency with modulation

9. Modulation

10. spectrum analyzer

11. amplitude

12. LSB

13. Buffer

14. Center frequency

15. Deviation ratio

16. a frequency of 20 kHz and above

17. 1.47

18. 0.56

19. 12.5

20. No effect

21. Armstrong system

22. balanced modulator

23. Crystal radio receiver

24. image frequency

25. A3E

26. R3E

27. J3E

28. B8E

29. C3F

30. H3E

31. G3E

32. Better fidelity

33. Higher value of operating power

34. Less audio power required

35. Interface to other radio services

36.  Selectivity

37. F3E

38. Modulation

39. Capture effect

40. 100 %

41. Frequency deviation

42. 112.5 kHz

43. Frequency modulation

44. Guard bands

45. All of the above

46. Modulation

47. Demodulation

48. Buffer amplifier

49. Depends on the type of modulation

50. All of the above

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

for signals entering the modulator?

A. Receiver noise

B. Excessive volume of receiver output

C. Oscillator disturbances

D. Distortion and splatter

52. Amplitude modulation causes the amount of transmitter

power to

A. Increase

B. Decrease

C. Remain the same

D. Double

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

increases by what percentage over that of the carrier

alone?

A. 25 %

B. 50 %

C. 75 %

D. 100 %

54. When the amplitude of the modulating voltage is

increased for AM, the antenna current will

A. Increase

B. Decrease

C. Remain constant

D. Decrease exponentially

55. An increase in transmitter power from 25W to 30W will

cause the antenna current to increase from 700mA to

A. 800 mA

B. 750 mA

C. 767 mA

D. 840 mA

56. A second modulating tone having the same amplitude

but a different frequency is added to the first at the input to

the modulator. The modulation index will be increased by a

factor of

A. sq. root of 3

B. sq. root of 2

C. 2

D. 3

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

frequency component of the modulated signal is

A. 1200 Hz

B. 5000 Hz

C. 1002.5 kHz

D. 2500 Hz

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

of 500 Hz and 700 Hz. Which one is a frequency

component of the modulated wave?

A. 1195 kHz

B. 1199.3 kHz

C. 1199.7 kHz

D. 1205 kHz

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

common-emitter configuration

A. Base modulation

B. Emitter modulation

C. Collector modulation

D. Both A and C

60. The RF signal injected into a balanced modulator is

10MHz and the modulating frequency is 1 kHz. Which

frequency, or frequencies, will not appear in the output?

A. 9.999 MHz

B. 10 MHz

C. 10.0001 MHz

D. Both A and B

61. Unwanted sidebands in SSB equipment can be

suppressed by one or more of the following methods.

A. Phasing method

B. Filter method

C. Decoder method

D. Both A and B

62. Envelope detection is concerned with the process of

A. Mixing

B. Heterodyning

C. Modulation

D. Rectification

63. Diagonal clipping in envelope detection will result in

A. Distortion

B. Phase reversal

C. Reduced sensitivity

D. Amplitude damage

64. Product detection requires the process of

A. Rectification

B. Heterodyning

C. Decoding

D. Phase shifting

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

A. Amplitude

B. Frequency

C. Phase angle

D. Both B and C

66. Frequency modulation and phase modulation are

collectively referred to as

A. Stereo

B. Angle modulation

C. High fidelity modulation

D. FCC modulation

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

what attribute of the modulating signal?

A. Angle

B. Frequency

C. Amplitude

D. Tone

68. A louder sound, when generating the modulating

waveform for FM, will cause a greater

A. Carrier amplitude

B. Angle amplitude

C. Distortion at the receiver

D. Frequency deviation

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

mW will cause a positive frequency deviation of 10 kHz,

what will be the frequency deviation for a negative change

of 10 mV in the level of the modulating signals?

A. 0

B. -5 kHz

C. +5 kHz

D. +0 kHz

70. A particular 15 kHz modulation tone results in a peak

frequency deviation of 75 kHz. What is the modulation

index?

A. 5

B. 15

C. 75

D. 3

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

carrier. A sideband frequency will be found at

A. 87.970 MHz

B. 87.985 MHz

C. 88.015 MHz

D. All of these

72. A device whose capacitance is deliberately made to be

a function of the applied voltage

A. Varactor diode

B. UJT

C. SAW

D. Variable capacitor

73. A reactance modulator is one method of obtaining

A. Indirect FM

B. Direct FM

C. Demodulation

D. Low frequency filtering

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

FM and as one element in the phse-locked loop.

A. AFC

B. AGC

C. VCO

D. LPF

75. _____ is a frequency change process, whereby the

phase deviation and frequency deviation are multiplied by

some fixed constant.

A. Translation

B. Multiplication

C. Division

D. Addition

76. A circuit that has the function of demodulating the

frequency-modulated signal.

A. AFC

B. Envelope detector

C. Decoder

D. Foster-Seeley discriminator

77. The ratio detector is superior to the slope detector

because

A. It is less sensitive to phase modulation

B. It is less sensitive to noise spikes

C. It is less sensitive to interference causing AM

D. Both B and C

78. One implementation of a pulse averaging discriminator

is

A. A free-running multivibrator

B. A crystal-controlled oscillator

C. A quartz crystal filter

D. A triggered multivibrator

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

pulse train should cause what change in its average value?

A. –10 %

B. –1 %

C. +1 %

D. +10 %

80. Two different signals can be coherent if they

A. Have the same amplitude

B. Are both sine waves of different frequencies

C. Originate in the same physical equipment

simultaneously

D. Have the same frequency

81. A quadrature detector requires that

A. Four gates bee provided

B. The inputs are coherent

C. The inputs are incoherent

D. The inputs are identical

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

A. Variable coherent output

B. VHF communication oscillator

C. Voltage-controlled oscillator

D. Vien-count oscillator (neutralized)

83. Identify an advantage, or advantages of a properly

designed FM system.

A. Relative immunity to atmospheric noise (lightning)

B. Reduced bandwidth required

C. No noise of any kind

D. The noise figure is inversely proportional to the

modulation index

84. The output of a balanced modulator

A. LSB and USB

B. LSB

C. USB

D. Carrier

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

0 to 1, the transmitted power is

A. Unchanged

B. Halved

C. Doubled

D. Increased by 50%

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

modulation?

A. Audio signal

B. Video signal

C. RF carrier

D. Binary coded pulses

87. If the unmodulated level peak carrier amplitude is

doubled in an AM signal, the perfect modulation is

________.

A. 20

B. 50

C. 100

D. 200

88. Balanced modulator circuit when inserted in the

equivalent suppresses the ___________

A. Carrier

B. Upper sideband

C. Lower sideband

D. Baseband signal

89. The carrier of a 100% modulated AM wave is

suppressed, the percentage power saving is __.

A. 100 %

B. 50 %

C. 83 %

D. 66.66 %

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

antenna current is also doubled, the AM system being used

is

A. H3E

B. J3E

C. C3F

D. A3E

91. 100% modulation in AM means a corresponding

increase in total power by _______.

A. 100 %

B. 50 %

C. 75 %

D. 25 %

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

A. 2 components

B. 3 components

C. 4 components

D. 2n + 1 components

93. A carrier signal has ________.

A. Constant peak amplitude

B. Frequency range of 20 – 20,000 Hz

C. A varying amplitude

D. The information

94. The modulating system is _________ if the modulating

frequency is doubled, the modulation index is halved, and

the modulating voltage remains constant.

A. Amplitude modulation

B. Phase modulation

C. Frequency modulation

D. Pulse modulation

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

modulating frequency is doubled?

A. No effect

B. Twice the original index

C. Four times the original index

D. One-half the original index

96. An AM transmitter is rated 1000 W at 100% modulation.

How much power required for the carrier?

A. 1000 W

B. 666.6 W

C. 333.3 W

D. 866.6 W

97. Standard way of designating AM

A. A3E

B. B3E

C. AHE

D. C3F

98. _____ is the circuit used to detect frequency modulated

signal.

A. Discriminator

B. Modulator

C. Modem

D. Detector

99. _____ is an information signal that is sent directly

without modulating any carrier.

A. C-band

B. Q-band

C. Baseband

D. Broadband

100. Both frequency and phase modulation utilize ______

modulation.

A. Digital

B. Phase

C. Amplitude

D. Angle

ANSWER

51. Distortion and splatter

52. Increase

53. 50 %

54. Increase

55. 767 mA

56. sq. root of 2

57. 1002.5 kHz

58. 1199.3 kHz

59. Both A and C

60. 10 MHz

61. Both A and B

62. Rectification

63. Distortion

64. Heterodyning

65. Both B and C

66. Angle modulation

67. Amplitude

68. Frequency deviation

69. -5 kHz

70. 5

71. All of these

72. Varactor diode

73. Direct FM

74. VCO

75. Multiplication

76. Foster-Seeley discriminator

77. Both B and C

78. A triggered multivibrator

79. +10 %

80. Have the same frequency

81. The inputs are coherent

82. Voltage-controlled oscillator

83. Relative immunity to atmospheric noise (lightning)

84. LSB and USB

85. Increased by 50%

86. RF carrier

87. 100

88. Carrier

89. 66.66 %

90. J3E

91. 50 %

92. 3 components

93. Constant peak amplitude

94. Frequency modulation

95. One-half the original index

96. 666.6 W

97. A3E

98. Discriminator

99. Baseband

100. Angle

(1) The first symbol indicates the type of modulation on the

transmitter carrier.

A—Amplitude modulation, double sideband with identical

information on each sideband.

F—Frequency modulation.

G—Phase modulation.

J—Single sideband with suppressed carrier.

P—Unmodulated pulse.

W—Cases not covered above, in which an emission

consists of the main carrier modulated, either

simultaneously or in a pre-established sequence, in a

combination of two or more of the following modes:

amplitude, angle, pulse.

(2) The second symbol indicates the type of signal

modulating the transmitter carrier.

0—No modulation.

1—Digital modulation, no subcarrier.

2—Digital modulation, modulated subcarrier.

3—Analog modulation.

(3) The third symbol indicates the type of transmitted

information.

A—Telegraphy for aural reception.

B—Telegraphy for machine reception.

C—Facsimile.

D—Data, telemetry, and telecommand.

E—Voice.

N—No transmitted information.

W—Combination of the above.

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

include the use of emissions for tone signals or signaling

devices whose sole functions are to establish and to

maintain communications, to provide automatic station

identification, and for operations in the Public Safety Pool,

to activate emergency warning devices used solely for the

purpose of advising the general public or emergency

personnel of an impending emergency situation.

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

be authorized only on frequencies above 25 MHz.

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

Safety Pool authorized in accordance with § 90.242, only

J3E emission will be authorized for telephony systems on

frequencies below 25 MHz.

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

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

emissions will be authorized.

(f) For radioteleprinter operations that may be authorized in

accordance with § 90.237, only F1B, F2B, G1B or G2B

emissions will be authorize above 25 MHz, and A1B or A2B

emissions below 25 MHz.

(g) For radiofacsimile operations that may be authorized in

accordance with § 90.237, only F3C or G3C emissions will

be authorized above 25 MHz, and A3C emissions below 25

MHz.

(h) [Reserved]

(i) For telemetry operations, when specifically authorized

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

be authorized.

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

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

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

emissions will be authorized.

(k) For radiolocation operations as may be authorized in

accordance with subpart F, unless otherwise provided for

any type of emission may be authorized upon a satisfactory

showing of need.

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

Pools utilizing digital voice modulation, in either the

scrambled or unscrambled mode, F1E or G1E emission will

be authorized. Authorization to use digital voice emissions

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

emission subject to the provisions of § 90.233.

(m) For narrowband operations in a 3.6 kHz maximum

authorized bandwith, any modulation type may be used

which complies with the emission limitations of § 90.209.

(n) Other emissions. Requests for emissions other than

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

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

requested emission will not cause more interference than

other currently permitted emissions.

101. It is the width of frequencies within the spectrum

occupied by a signal and used by the signal for conveying

information.

A. Band

B. Bandwidth

C. Electronic spectrum

D. Frequency band

102. Which transmit only one sideband?

A. H3E

B. C3F

C. A3E

D. B8E

103. ______ is kind of modulation in which the modulated

wave is always present.

A. Carrier modulation

B. Continuous modulation

C. Log-periodic modulation

D. Square-wave modulation

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

between pulses.

A. Pulse modulation

B. FSK

C. QAM

D. PAM

105. What describes the amount of amplitude change

present in an AM waveform?

A. Percent modulation

B. Modulation constant

C. Envelope of modulation

D. Coefficient of modulation

106. _______ is a form of amplitude distortion introduced

when the positive and negative alternations in the AM

modulated signals are not equal.

A. Envelope distortion

B. Spurious emission

C. Carrier shift

D. Johnson noise

107. What is the advantage of phase modulation over direct

FM frequency modulation?

A. Multipliers can be used

B. The deviation is smaller

C. Simplicity and practicality

D. The oscillator is crystal-controlled

108. If the spectrum is shifted in frequency with no other

changes, this is known as

A. Frequency multiplication

B. Sideband movement

C. Baseband reorientation

D. Frequency translation

109. A device which is capable of causing frequency

translation

A. High-Q tank circuit

B. Balanced modulator

C. Low-Q tank circuit

D. IF strip

110. If the frequency of each component in a signal

spectrum is increased by the same fixed amount, this

known as

A. Modulation

B. Frequency translation

C. Up conversion

D. Both B and C

111. A particular amplifier is designed to be a frequency

doubler. If the input signal frequency is 15.4 MHz, a circuit

in the output will be tuned to

A. 7.7 MHz

B. 15.4 MHz

C. 30.8 MHz

D. 61.6 MHz

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

achieve a maximum phase deviation of 0.2 radian. After

passing through a frequency tripler, the maximum phase

deviation will be

A. 0.2 radian

B. 0.3 radian

C. 0.4 radian

D. 0.6 radian

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

be

A. Active

B. Passive

C. Linear

D. Nonlinear

114. A particular amplifier circuit used for frequency

doubling.

A. Push-push

B. Push-pull

C. Pull-push

D. Pull-pull

115. Frequency division is useful in the implementation of a

A. AM demodulator

B. Frequency synthesizer

C. AGC circuit

D. FM demodulator

116. Frequency division by 12 will require how many flip-

flops in the counter?

A. 3

B. 4

C. 6

D. 12

117. Identify an electronic device, not specifically designed

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

A. Wien bridge

B. Colpitts oscillator

C. Balanced modulator

D. Butterworth filter

118. A particular frequency synthesizer contains only a

single crystal. What words describe this synthesizer?

A. Crystal modulated

B. Inexact

C. Indirect

D. Deficient

119. A recognizable feature of a CW transmitter is

A. Keyed transmitter

B. Power amplification

C. Frequency generation

D. All of these

120. The term “pulling” refers to

A. The change of the crystal oscillator frequency by loading

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

C. Loading on the transmitter caused by the antenna

connection

D. Reduction of the power supply terminal voltage as the

transmitter is keyed.

121. When frequency modulation is achieved by initial

phase modulation, this is called

A. Angular modulation

B. Direct FM

C. Indirect FM

D. Indirect synthesis

122. A disadvantage of direct FM is the need for

A. AGC

B. AFC

C. A frequency synthesizer

D. Phase modulation

123. Direct FM can be achieved by

A. A reactance tube modulator

B. A varactor diode

C. And AGC circuit

D. Both A and B

124. A receiver in which all RF amplifier stages require

manual tuning to the desired RF is called

A. Superheterodyne

B. Autodyne

C. TRF

D. AFC

125. Why is it often necessary to precede the demodulator

by amplifier stages in a receiver?

A. To improve fidelity

B. To reduce receiver noise

C. To eliminate image response

D. Weak antenna signals

126. A serious disadvantage of the TRF receiver.

A. Bandwidth variations over the tuning range

B. The weight and cost

C. The requirements for a closely regulated power supply

D. The requirements for a half-wave antenna

127. Identify which is not a part of a super heterodyne

receiver.

A. Local oscillator

B. Modulator

C. IF amplifier

D. Demodulator

128. Which major element will not be found in every

superheterodyne receiver?

A. R–F amplifier

B. Mixer

C. Local oscillator

D. IF amplifier

129. Which major element of a superheterodyne receiver

must be nonlinear?

A. R-F amplifier

B. Mixer

C. Local oscillator

D. IF amplifier

130. The change of the modulated carrier frequency from

the original RF to the IF of the super heterodyne receiver is

known as

A. Frequency multiplication

B. Frequency allocation

C. Frequency substitution

D. Frequency translation

131. The key to achieving receiver sensitivity is the

reduction of

A. Image response

B. Mixer harmonic products

C. Spurious frequency response

D. Internal noise

132. Which of the following receiver design objectives is not

impossible?

A. Elimination of galactic noise

B. Elimination of atmospheric noise

C. Elimination of man-made noise

D. Reduction of receiver internal noise

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

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

A. Smaller

B. The same

C. Greater

D. Infinite

134. The characteristic of a receiver that specifies the self-

generated noise.

A. Noise immunity

B. Noise factor

C. Noise figure

D. Noise margin

135. An FM receiver with an I-F of 10.7 MHz is tuned to

98.7 MHz. What is the numerical value of the image

frequency?

A. 77.3 MHz

B. 88.0 MHz

C. 109.4 MHz

D. 120.1 MHz

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

which frequency in the FM broadcast band will this be the

image frequency?

A. 21.4 MHz

B. 88.5 MHz

C. 99.2 MHz

D. 110.7 MHz

137. The ratio of the super heterodyne receiver response at

the desired carrier frequency to that at the image frequency

is called

A. The sensitivity

B. The selectivity

C. The image frequency

D. The image rejection ratio

138. The core of an IF transformer usually contains

A. Teflon

B. Computer nylon

C. Powdered iron

D. Laminated steel

139. Shape factor is a measure of

A. Bandwidth

B. Skirt steepness

C. Coupling coefficient

D. Critical coupling

140. _______ is the function which tends to maintain the

sound volume level of a voice receiver nearly constant for a

large signal strength range.

A. Squelch

B. Muting

C. AGC

D. AFC

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

absence of transmitted carrier.

A. Squelch

B. Muting

C. AGC

D. AFC

142. What device is incorporated in a communications

receiver to reduce impulse noise?

A. Front-end processor

B. Squelch circuit

C. AGC

D. Noise blanker

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

2.4 kHz in the I-F circuitry is optimum?

A. FM voice

B. Double-sideband AM voice

C. FSK data

D. SBB voice

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

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

A. A lower frequency carrier

B. The audio voice information

C. A Morse-code signal

D. The upper or lower set of sidebands

145. In a capacitive type, reactance-tube modulator

connected across an oscillator tuned circuit, a more

negative voltage on the grid of the reactance tube will

cause

A. An increase of the oscillator frequency

B. An decrease of oscillator frequency

C. An increase of the reactance-tube capacitance

D. An increase of the reactance tube ac plate current

146. The limiting condition for sensitivity in a

communications receiver is

A. The noise floor of the receiver

B. Power supply output ripple

C. The two-tone intermodulation distortion

D. The input impedance to the detector

147. When a communications receiver is tuned to a strong

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

The fault cannot be caused by a/an

A. Defective IF stage

B. Defective local oscillator

C. Defective RF stage

D. Open circuit in the AGC’s filter capacitor

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

signals from a very strong station are superimposed on

other signals being received

A. Cross-modulation interference

B. Intermodulation interference

C. Receiver quieting

D. Capture effect

149. The limiter stage of an FM receiver

A. Behaves as a low-pass filter

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

C. Behaves as a high-pass filter

D. Behaves as a bandstop filter

150. Motorboating (low-frequency oscillations) in an

amplifier can be stopped by

A. Grounding the screen grid

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

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

capacitor

D. Grounding the plate

151. An effect in which, the modulation of an unwanted

signal is transferred to the desired carrier.

A. Crossmodulation

B. Intermodulation

C. Modulation mixing

D. Image-channel interference

152. Leads should be kept as short as possible in radio

circuit so that

A. Skin effect is reduced

B. There is less hysteresis effect

C. There is less dielectric loss

D. Stray coupling is minimized

153. The number of voice transmissions that can be packed

into a given frequency band for amplitude-

compandored single-sideband systems over conventional

FM-phone systems.

A. 2

B. 18

C. 16

D. 4

154. Neutralization of an RF amplifier stage can be

necessary in order to

A. Increase the amplifier’s gain

B. Prevent the generation of spurious oscillations

C. Reduce the amplifier’s gain

D. Reduce the level of the output harmonics

155. The ability of a communications receiver to perform

well in the presence of strong signals outside the band of

interest is indicated by what parameter?

A. Blocking dynamic range

B. Noise figure

C. Signal-to-noise ratio

D. Audio output

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

A. Tuner, local oscillator, detector, AF amplifier

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

C. Local oscillator, RF amplifier, frequency discriminator,

detector

D. Tuner, IF amplifier, detector, AF amp

157. Occurs during CW reception if too narrow a filter

bandwidth is used in the IF stage of a receiver

A. Filter ringing

B. Undesired signals will reach the audio stage

C. Output-offset overshoot

D. Cross-modulation distortion

158. What stage mainly determines a communication

receiver’s sensitivity?

A. IF amplifier

B. Mixer stage

C. Detector stage

D. RF amplifier

159. What is the main advantage of FM over AM?

A. Better signal-to-noise-ratio

B. Narrower bandwidth

C. Greater propagation range

D. Total freedom from adjacent-channel interference

160. An amplitude modulation created in an amplifier before

the final RF stage.

A. Low-level modulation

B. High-level modulation

C. Direct modulation

D. Indirect modulation

161. Receiver desensitizing can be reduced by

A. Increasing the transmitter audio gain

B. Decreasing the receiver squelch gain

C. Increasing the receiver bandwidth

D. Ensuring good RF shielding between the transmitter

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

commonly one and the highest audio frequency is generally

limited to

A. 300 Hz

B. 10,000 Hz

C. 3,000 Hz

D. 7,500 Hz

163. A type of emission is produced when an amplitude

modulated transmitter is modulated by a facsimile signal

A. A3F

B. F3F

C. A3C

D. F3C

164. Where is the noise generated which primarily

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

marine band receiver?

A. In the detector

B. In the atmosphere

C. In the ionosphere

D. In the receiver front end

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

A. Installing a filter at the receiver

B. Using a filter at the receiver

C. Increasing the receiver’s RF gain while decreasing the

AF

D. Adjusting the pass-band tuning

166. What is the emission designation for FM telephony?

A. F3E

B. G3E

C. J3E

D. H3E

167. What is the cause of receiver desensitizing?

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

B. Audio gain adjusted too low

C. Squelch gain adjusted too high

D. Squelch gain adjusted too low

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

frequency deviation is directly proportional to the

A. Carrier amplitude only

B. Amplitude of the modulating tone and frequency of the

carrier

C. Carrier frequency only

D. Modulating signal amplitude only

169. An RF stage precedes the mixer stage in a

superheterodyne receiver. One advantage of including this

RF stage is

A. Better selectivity

B. Better rejection ratio

C. Greater sensitivity

D. Improved signal-to-noise-ratio

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

A. Dynamic range and third-order intercept

B. Cost and availability

C. Bandwidth and noise figure

D. Intermodulation distortion and dynamic range

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

bandwidth in the IF section of a receiver?

A. Undesired signals will reach the audio stage

B. Output-offset overshoot

C. Thermal-noise distortion

D. Filter ringing

172. A system containing a limiter stage, a discriminator,

and a de-emphasis circuit?

A. Direct FM transmitter

B. Indirect FM transmitter

C. Single sideband AM receiver

D. FM receiver

173. The limiter stage of an FM receiver

A. Prevents any amplitude modulation of the IF signal

B. Limits the amount of frequency deviation in the IF signal

C. Limits the overall bandwidth of the IF stages

D. Corrects any deviation in carrier frequency

174. High selectivity occurs when the degree of coupling

between a receiver’s RF stages is

A. Tight

B. Loose

C. Critical

D. Adjusted for maximum power transfer

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

amplitude and the frequency of the tone are both doubled,

the amount of the deviation is

A. Doubled

B. Unchanged

C. Halved

D. Multiplied by four

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

a single-sideband receiver.

A. 1 kHz

B. 2.4 kHz

C. 4.2 kHz

D. 4.8 kHz

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

circuit is the

A. Crystal

B. Resistor

C. Transformer

D. Diode

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

A. Avoid the requirement of neutralizing the stage

B. Raise the input impedance

C. Lower the output impedance

D. Obtain maximum power output

179. The AM detector performs two basic functions in the

receiver.

A. Rectifies and filters

B. Amplifiers and filters

C. Buffer and amplifier

D. Buffer and detector

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

A. Direct FM modulator circuit

B. AFC circuit in a direct FM transmitter

C. Phase-modulator circuit

D. All of these

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

A. Crystal filter

B. Insulating enclosures around the receiver

C. Wave trap

D. RF stage

182. What is the emission C3F?

A. RTTY

B. SSB

C. Television

D. Modulated CW

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

RF power amplifier stage in an unmodulated carrier

transmitter when the PEP output is 500 W?

A. Approximately 1000 W

B. Approximately 800 W

C. Approximately 250 W

D. Approximately 600 W

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

responsible for drastically reducing the effect of static noise

during the reception of a signal

A. De-emphasis circuit

B. Mixer stage

C. Squelch circuit

D. Limiter stage

185. The letters “SSSC” stands for

A. Single sideband, single carrier

B. Suppressed sideband, single channel

C. Suppressed sideband, single carrier

D. Single sideband, suppressed carrier

186. For many types of voices, what is the ratio of PEP-to-

average power during a modulation peak in a single-

sideband phone signal?

A. Approximately 1.0 to 1

B. Approximately 25 to 1

C. Approximately 100 to 1

D. Approximately 2.5 to 1

187. In most mixers, the oscillator frequency is ______ than

the carrier frequency of the input signal.

A. Higher

B. Lower

C. The same

D. 10 kHz above

188. Features of a transmitter’s buffer stage include

A. High stage

B. Harmonic generation

C. Improvement in frequency stability of the oscillator

D. Low input impedance

189. Type of emission produced when an amplitude

modulated transmitter is modulated by a television signal

A. F3F

B. A3C

C. F3C

D. A3F

190. A network is

A. A network consisting entirely of four inductors or four

capacitors

B. A power incidence network

C. An antenna matching network that is isolated from

ground

D. A network consisting of one inductor and two capacitors

191. How is G3E FM-phone signals produced?

A. A network consisting modulator on the audio amplifier

B. With a reactance modulator on the final amplifier

C. With a reactance modulator on the oscillator

D. With a balanced modulator on the oscillator

192. A way of eliminating auto interference to radio

reception

A. Installing resistive spark plugs

B. Installing capacitive spark plugs

C. Installing resistors in series with the spark plugs

D. Installing two copper-braid ground strips

193. The carrier in an AM transmitter is the

A. Transmitter’s output signal when the modulation is

present

B. Transmitter’s output signal when the modulation is zero

C. Output signal from the crystal oscillator

D. RMS value of the AM signal

194. What stage feeds the discriminator of an FM receiver?

A. Local oscillator

B. Mixer stage

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

D. Buffer

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

input and the audio signal output.

A. Limiter

B. Audio amplifier

C. IF amplifier

D. Discriminator

196. What is capture effect?

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

receiver

B. The loudest signal received is the only demodulated

signal

C. All signals on a frequency are demodulated by an AM

receiver

D. The weakest signal received is the only demodulated

signal

197. A double-sideband phone signal can be generated by

A. Feeding a phase-modulated signal into a low-pass filter

B. Modulating the plate voltage of a class-C amplifier

C. Using a balanced modulator followed by a filter

D. Detuning a Hartley oscillator

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

the signal-to-noise ratio of

A. High modulating frequencies

B. Low modulating frequencies

C. All modulating frequencies

D. Frequencies carrier

199. The result of cross-modulation is that

A. The modulation of an unwanted signal is heard on the

desired signal

B. A decrease in modulation level of transmitted signals

C. Of receiver quieting

D. Of inverting sidebands in the final stage of the amplifier

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

A. FM transmitter

B. FM receiver

C. VHF transmitter

D. VHF receiver

101. Bandwidth

102. H3E

103. Continuous modulation

104. Pulse modulation

105. Coefficient of modulation

106. Carrier shift

107. The oscillator is crystal-controlled

108. Frequency translation

109. Balanced modulator

110. Both B and C

111. 30.8 MHz

112. 0.6 radian

113. Nonlinear

114. Push-push

115. Frequency synthesizer

116. 4

117. Balanced modulator

118. Indirect

119. All of these

120. The change of the crystal oscillator frequency by loading

121. Indirect FM

122.

123. Both A and B

124. TRF

125. Weak antenna signals

126. Bandwidth variations over the tuning range

127. Modulator

128. R–F amplifier

129. Mixer

130. Frequency translation

131. Internal noise

132. Reduction of receiver internal noise

133. Smaller

134. Noise figure

135. 120.1 MHz

136. 88.5 MHz

137. The image rejection ratio

138. Powdered iron

139. Skirt steepness

140. AGC

141. Squelch

142. Noise blanker

143. SBB voice

144. The audio voice information

145. An increase of the oscillator frequency

146. The noise floor of the receiver

147. Open circuit in the AGC’s filter capacitor

148. Cross-modulation interference

149. Limits the amplitude of the IF signal to the required level

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

151. Crossmodulation

152. Stray coupling is minimized

153. 4

154. Prevent the generation of spurious oscillations

155. Blocking dynamic range

156. RF amplifier, mixer, IF amplifier, AF amplifier

157. Filter ringing

158. IF amplifier

159. Better signal-to-noise-ratio

160. Low-level modulation

161. Ensuring good RF shielding between the transmitter

162. 3,000 Hz

163. A3C

164. In the receiver front end

165. Installing a filter at the receiver

166. F3E

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

168. Amplitude of the modulating tone and frequency of the carrier

169. Better rejection ratio

170. Bandwidth and noise figure

171. Undesired signals will reach the audio stage

172. FM receiver

173. Prevents any amplitude modulation of the IF signal

174. Loose

175. Multiplied by four

176. 2.4 kHz

177. Resistor

178. Avoid the requirement of neutralizing the stage

179. Rectifies and filters

180. All of these

181. Insulating enclosures around the receiver

182. Television

183. Approximately 1000 W

184. Limiter stage

185. Single sideband, suppressed carrier

186.  Approximately 2.5 to 1

187. Higher

188. Improvement in frequency stability of the oscillator

189. A3F

190. A network consisting of one inductor and two capacitors

191. With a reactance modulator on the oscillator

192. Installing resistive spark plugs

193. Transmitter’s output signal when the modulation is zero

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

195. Discriminator

196. The loudest signal received is the only demodulated signal

197. Modulating the plate voltage of a class-C amplifier

198. High modulating frequencies

199. The modulation of an unwanted signal is heard on the desired

signal

200. FM receiver

201. What is emission F3F?

A. AM

B. Facsimile

C. Television

D. RTTY

202. What type of emission is produced when a frequency

modulated transmitter is modulated by a facsimile signal?

A. F3C

B. A3C

C. F3F

D. A3F

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

result the two modulated signals are mixed in the final RF

stage of both transmitters. What is the resultant effect on

other station?

A. Harmonic interference

B. Intermodulation interference

C. Spurious interference

D. Crossmodulation interference

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

caused by the signal of a nearby station transmitter in the

same frequency band?

A. Quieting

B. Cross-modulation interference

C. Squelch gain rollback

D. Desensitizing

205. What is the bandwidth occupied by the carrier, both

sidebands and harmonics?

A. Authorized bandwidth

B. Bandwidth of emission and occupied bandwidth

C. Operating bandwidth

D. All of these

206. A class-C RF amplifier is collector amplitude

modulated and its average dc level collector current does

not change. This means

A. A normal condition

B. Excessive drive to the base

C. Insufficient drive to the base

D. Insufficient audio modulation

207. What determines the percentage modulation of an FM

transmitter?

A. Amplitude of the carrier

B. Modulating frequency

C. Carrier frequency

D. Amplitude of the modulating signal

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

A. Maximum frequency swing to the highest modulating

frequency

B. Operating frequency of the assigned frequency

C. Frequency swing to the modulating frequency

D. Highest modulating frequency to the minimum frequency

209. The main purpose of the beat frequency oscillator

(BFO) is to generate

A. A 1 kHz not for Morse reception

B. Aid in the reception of weak voice-modulated signals

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

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

frequency

210. Normally, a linear class BRF power amplifier operates

with a bias approximately equal to

A. Twice cut-off

B. Ten times cut-off value

C. 50% of cut-off value

D. Projected cut-off

211. The purpose why an RF amplifier is operated under

linear class-B conditions (as opposed to class-C) is to

A. Generate only even harmonics

B. Generate only odd harmonics

C. Increase the efficiency

D. Amplify of an AM signal

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

signal from a very strong station are superimposed on other

signal being received.

A. Cross-modulation interference

B. Intermodulation distortion

C. Receiver quieting

D. Capture effect

213. _________ is the amplitude of the maximum negative

excursion of a signal as viewed on an oscilloscope.

A. Peak-to-peak voltage

B. Inverse peak positive voltage

C. RMS voltage

D. Peak negative voltage

214. The type of emission that suffer most from selective

fading.

A. CW and SSB

B. SSB and TV

C. FM and double sideband AM

D. SSTV and CW

215. In an FM-phone signal, ________ is the ratio between

the actual frequency deviation to the maximum frequency

deviation.

A. FM compressibility

B. Modulating index

C. Percentage of modulation

D. Quieting index

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

one FM-phone signal by another FM-phone signal.

A. Capture effect

B. Desensitization

C. Cross-modulation interference

D. Frequency discrimination

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

optimum for what type of signals?

A. SSB voice

B. Facsimile

C. FM

D. Double-sideband AM

218. If the envelope of modulation is constant in amplitude

this means

A. Zero beat

B. Under-modulation

C. Zero-modulation

D. Over-modulation

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

modulation factor of 12.5 and a modulating frequency of 10

kHz?

A. 20 kHz

B. 270 kHz

C. 250 kHz

D. 45 kHz

220. Amplitude modulation is the same as

A. Linear mixing

B. Analog multiplication

C. Signal summation

D. Multiplexing

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

_______ on a diode modulator.

A. Tuned circuit

B. Transformer

C. Capacitor

D. Inductor

222. One of the following can produce AM.

A. Having the carrier vary a resistance

B. Having the modulating signal vary a capacitance

C. Varying the carrier frequency

D. Varying the gain of an amplifier

223. Amplitude modulators that vary the carrier amplitude

with the modulating signal by passing it through an

attenuator network is the principle of

A. Rectification

B. Amplification

C. Variable resistance

D. Absorption

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

frequencies?

A. Varactor diode

B. Thermistor

C. Cavity resonator

D. PIN diode

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

What is the peak-to-peak amplitude of the modulating

signal for 100 percent modulation?

A. 24 V

B. 48 V

C. 96 V

D. 120 V

226. What circuit recovers the original modulating

information from an AM signal?

A. Modulator

B. Demodulator

C. Mixer

D. Crystal set

227. What is the most commonly used amplitude

demodulator?

A. Envelope detector

B. Balanced modulator

C. Mixer

D. Crystal set

228. What circuit generates the upper and lower sidebands

and suppresses the carrier?

A. Amplitude modulator

B. Diode detector

C. Class C amplifier

D. Balanced modulator

229. _________ is a widely used balanced modulator.

A. Diode bridge circuit

B. Full-wave bridge rectifier

C. Lattice modulator

D. Balanced bridge modulator

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

A. Variable resistors

B. Switches

C. Rectifiers

D. Variable capacitors

231. The output of a balanced modulator is

A. AM

B. FM

C. SSB

D. DSB

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

balanced modulator is a

A. Differential amplifier

B. Rectifier

C. Bridge

D. Constant current source

233. The most commonly used filter in SSB generators

uses

A. LC networks

B. Mechanical resonators

C. Crystals

D. RC networks and op amps

234. In the phasing method of SSB generation, one

sideband is canceled out due to

A. Phase shifting

B. Sharp selectivity

C. Carrier suppression

D. Phase inversion

235. A balanced modulator used to demodulate a SSB

signal is call a/an

A. Transponder

B. Product detector

C. Converter

D. Remodulator

236. Frequency translation is done with a circuit called a

A. Summer

B. Multiplier

C. Divider

D. Mixer

237. Mixing for frequency conversion is the same as

A. Rectification

B. AM

C. Linear summing

D. Filtering

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

over AM?

A. Greater efficiency

B. Noise immunity

C. Capture effect

D. Lower complexity and cost

239. The primary disadvantage of FM is its

A. Higher cost and complexity

B. Excessive use of spectrum space

C. Noise susceptibility

D. Lower efficiency

240. Noise is primarily

A. High-frequency spikes

B. Lowe-frequency variations

C. Random level shifts

D. Random frequency variations

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

A. Modulator

B. Demodulator

C. Limiter

D. Low-pass filter

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

amplified by what type of amplifier?

A. Class A

B. Class B

C. Class C

D. All of the above

243. SSB means

A. Single sideband with suppressed carrier

B. Single sideband with carrier

C. Double sideband with no carrier

D. Single sideband with reduced carrier

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

A. Transformer

B. Resonant circuit

C. Filter

D. Phase-shift circuit

245. What is the output of a balanced modulator?

A. AM

B. DSB

C. SSB

D. ISB

246. The acronym SSSC refer to

A. Suppressed sideband, single carrier

B. Suppressed sideband, suppressed carrier

C. Single sideband, suppressed carrier

D. Single sideband, single carrier

247. Which process occurs in the receiver?

A. Demodulation

B. Reception

C. Modulation

D. Recreation

248. What is usually used to demodulate SSB or CW

signal?

A. PLL

B. BFO

C. Ratio detector

D. All of these

249. Which of the following is the most widely used

amplitude modulator

A. Diode detector

B. PLL circuit

C. VCO

D. All of these

250. Which of the following is the most widely used

balanced modulator

A. Full-wave bridge circuit

B. Balanced bridge modulator

C. Lattice modulator

D. None of these

251. A method that applied the modulated wave to the

vertical deflection circuit of the oscilloscope and the

modulating signal to the horizontal deflection circuit.

a. Trapezoidal method

b. Circular method

c. Square method

d. Any method

252. The heart of all methods of single-sideband

modulation and demodulation

a. Modulator

b. Balanced modulator

c. Modulation

d. demodulation

253. If the frequency and phase are parameters of carrier

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

___________-cover both.

a. Amplitude modulation

b. Frequency modulation

c. Phase modulation

d. Angle modulation

254. In FM radio communication system, narrow-band

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

a. Improves signal to noise ration

b. Reduces interchannel interference

c. Provides maximum coverage for a given amount of

power

d. All of the above

255. Radio transmitter basically consists of two principal

parts, one reproducing a carrier frequency and one for

__________.

a. IF Frequency

b. RF Frequency

c. Modulating Frequency

d. Power

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

frequency as possible over as long as time interval as

possible.

a. Receiver Noise Factor

b. Selectivity

c. Sensitivity

d. Frequency stability

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

proximity. This results into the sum and difference

frequencies of two carriers.

a. Intermodulation effect

b. Intermodulation interference

c. Intermodulation product

d. intermodulation

258. _________ is a continuous frequency capable of being

modulated or impressed with a second information carrying

signal.

a. Carrier frequency

b. Center frequency

c. IF frequency

d. RF frequency

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

the approximate equivalent circuit of the _____ in series

with a ________.

a. Diode, capacitor

b. Diode, resistor

c. Capacitor, resistor

d. Any of these

260. The name varactor comes from variable _________.

a. Resistor

b. Capacitor

c. Diode

d. reactor

261. 75 microseconds pre-emphasis time is used in

__________.

a. FM

b. AM

c. TV

d. None of these

262. Recovers the modulating voltage from the frequency

modulation by utilizing the phase angle shift between

primary and secondary voltages of tuned oscillators.

a. Direct method

b. Indirect method

c. Foster-Seeley discriminator

d. Slope detector

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

signal and stabilized receptions.

a. Automatic Gain Control

b. Automatic Frequency Control

c. Muscle Control

d. Automatic Frequency Gain Control

264. Are amplifier circuits that are used to eliminate

amplitude modulation and amplitude-modulated noise from

received FM Signals before detection.

a. Demodulators

b. Diode detector

c. Amplitude limiters

d. None of these

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

radiated power, find the modulation index.

a. 50 percent

b. 53.4 percent

c. 26.2 percent

d. 32.3 percent

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

Each carrier is modulated by a signal with a 5 kHz

bandwidth. Is there interference from the sideband?

a. Yes

b. No

c. Maybe

d. Secret

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

peak value of 230 V. What is the modulation index

a. 0.35

b. 0.533

c. 0.652

d. 0.42

268. New frequencies outside the regular AM spectrum are

called ___________.

a. Distortion

b. Interference

c. Splatter

d. Harmonic

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

modulation suppresses 50% of the carrier, and the

suppressed carrier power goes to the sidebands. How

much power is in the sidebands?

a. 116.67 W

b. 233.33 W

c. 175 W

d. 350 W

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

from its original value of 30 W. What value must the carrier

be reduced?

a. 30000 W

b. 0.03 W

c. 300 W

d. 0.003 W

271. ___________, which further amplifies the signal and

has the bandwidth and passband shaping appropriate for

the received signal.

a. RF stage

b. Mixer and local oscillator stage

c. IF stage

d. AF stage

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

Bessel functions

a. Approximate bandwidth

b. Narrow-band Bandwidth

c. Carson’s rule

d. Wideband bandwidth

273. The complete series of stages for reproducing the FM

signal with the desired carrier and deviation is the _______.

a. Modulator

b. Exciter

c. IF stage

d. RF stage

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

high fidelity music background/broadcast..

a. Monophonic

b. Stereophonic

c. Stereonic

d. SCA

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

response roll-off versus frequency.

a. Foster Seeley

b. Slope detector

c. Diode detector

d. Quadrature detector

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

____ and 1.

a. 2

b. 5

c. 0

d. 3

277. This form of modulation is also known as independent

sideband emission.

a. A3E

b. R3E

c. H3E

d. B8E

278. An attenuated carrier is reinserted into the SSB signal

to facilitate receiver tuning and demodulation.

a. A3E

b. R3E

c. H3E

d. B8E

279. Standard AM used for broadcasting

a. A3E

b. R3E

c. H3E

d. B8E

280. Single sideband, suppressed carrier in which the

carrier is suppressed by at least 45 dB in the transmitter.

a. A3E

b. R3E

c. H3E

d. B8E

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

compared to the amplitude of the modulating signal is

called _______.

a. Index

b. Deviation ratio

c. Carrier frequency

d. Deviation frequency

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

remains ___________ at all times.

a. Varying

b. Dependent

c. Constant

d. variable

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

required minimum span to attain 100% modulation?

a. 30 V

b. 20 V

c. 0 V

d. None of these

284. DZMM having a carrier frequency of 630 kHz is

modulated by 2.6 kHz audio signal having an amplitude of

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

frequency at 0.35 modulation index?

a. 57.6 V

b. 107.14 V

c. 206.5 V

d. 86.2 V

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

what is the modulation index?

a. 50%

b. 75%

c. 90%

d. 100%

286. If the increase power is 180 watts at 1

kW unmodulated output power the modulation index is

_________.

a. 75%

b. 60%

c. 50%

d. 25%

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

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

at 100% modulation index?

a. 25 kW

b. 2 kW

c. 2.5 kW

d. 4 kW

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

broadcast produced 20 kW carrier power, at what

modulation index should the antenna rise at 108.63 A?

a. 20%

b. 50%

c. 60%

d. 80%

289. ________ used a phase detector to compare the

phase and frequency of the received signal to the VCO

output.

a. PIL

b. PAL

c. PLL

d. PLI

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

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

center carrier frequency. How many dB down is the output

at full deviation?

a. 9 dB

b. -18 dB

c. 18 dB

d. -9 dB

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

operation. The voltage gain between the RF input and the

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

assuming equal resistance?

a. 75.6 mV

b. 26.67 uV

c. 52.3 uV

d. 49.6 uV

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

Hz deviation. It undergoes x36 multiplication, followed by

mixing with a 34.5 MHz signal and re-multiplication by 72.

What is the final carrier and deviations?

a. 5076 MHz, ± 2592 MHz

b. 2592 MHz, ± 259.2 kHz

c. 2592MHz, ± 5076 MHz

d. 259.2 MHz, ± 108 kHz

293. For standard commercial broadcast FM, the deviation

ratio is ________.

a. 15

b. 75

c. 5

d. 10

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

kHz modulation signal. What is the approximate deviation

to be used?

a. 35 kHz

b. 65 kHz

c. 25 kHz

d. 15 kHz

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

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

triples?

a. 6.66

b. 2.22

c. 4.12

d. 0.20

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

and low tracking. What is the image frequency?

a. 89.3 MHz

b. 78.6 MHz

c. 52.5 MHz

d. 35.2 MHz

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

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

nominal value?

a. 2.06

b. 3.02

c. 1.03

d. 5.06

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

capacitor and 0.25 mH inductor, what s the resonant

frequency of the actual capacitor value is +20% of the

nominal value?

a. 1.006 MHz

b. 0.9188 MHz

c. 3.625 MHz

d. 2.00123 MHz

299. “Front end” is also called _________.

a. IF stage

b. AF stage

c. RF stage

d. None of these

300. Undesired signal on the other side of the local

oscillator output will have the same difference frequency

and pass into the IF amplifier.

a. Carrier frequency

b. Sum frequency

c. Difference frequency

d. Image frequency

201. Television

202. F3C

203. Intermodulation interference

204. Desensitizing

205. Bandwidth of emission and occupied bandwidth

206. A normal condition

207. Amplitude of the modulating signal

208. Maximum frequency swing to the highest modulating

frequency

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

210. Projected cut-off

211. Amplify of an AM signal

212. Cross-modulation interference

213. Peak negative voltage

214. FM and double sideband AM

215. Percentage of modulation

216. Capture effect

217. Double-sideband AM

218. Zero-modulation

219. 270 kHz

220. Linear mixing

221. The tuned circuit

222. Having the carrier vary a resistance

223. Variable resistance

224. PIN diode

225. 96 V

226. Demodulator

227. Envelope detector

228. Balanced modulator

229. Lattice modulator

230. Switches

231. DSB

232. Differential amplifier

233. Crystals

234. Phase shifting

235. Product detector

236.  Mixer

237. Linear summing

238. Lower complexity and cost

239. Excessive use of spectrum space

240. High-frequency spikes

241. Limiter

242. Class C

243. Single sideband with suppressed carrier

244. Filter

245. DSB

246. Single sideband, suppressed carrier

247. Demodulation

248. BFO

249. Diode detector

250. Lattice modulator

251. Trapezoidal method

252. Balanced modulator

253. Angle modulation

254. All of the above

255. Modulating Frequency

256. Frequency stability

257. Intermodulation interference

258. Carrier frequency

259. Capacitor, resistor

260. reactor

261. FM

262. Foster-Seeley discriminator

263. Automatic Frequency Control

264. Amplitude limiters

265. 53.4 percent

266. No

267. 0.533

268. Splatter

269. 233.33 W

270. 0.03 W

271. IF stage

272. Carson’s rule

273. Exciter

274. Stereophonic

275. Slope detector

276. 0

277. B8E

278. R3E

279. A3E

280. H3E

281. Deviation ratio

282. Constant

283. 0 V

284. 107.14 V

285. 100%

286. 60%

287. 2.5 kW

288. 60%

289. PLL

290. 18 dB

291. 26.67 uV

292. 2592 MHz, ± 259.2 kHz

293. 5

294. 65 kHz

295. 0.20

296. 78.6 MHz

297. 1.03

298. 0.9188 MHz

299. RF stage

300. Image frequency

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

modulator

a. SSB

b. ISB

c. AM

d. DSB

302. Which of the following components is used to produce

AM at very high frequencies?

a. Cavity resonator

b. PIN diode

c. Varactor

d. Thermistor

303. A third symbol emission which represent

data transmission including telemetry, and telecommand

a. B

b. D

c. C

d. N

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

a. None of these

b. Sidebands

c. Both the sidebands and the carrier

d. Carrier

305. Determine the modulation index of an standard FM

broadcast having a hypothetical maximum carrier frequency

deviation of ±12 kHz and a maximum modulating frequency

pf 4kHz.

a. 9

b. 6

c. 3

d. 4

306. The process by which the intelligence signals normally

at lower frequency are removed from

the transmission frequency after it is received in the

receiver station.

a. Detection

b. Demodulation

c. Amplification

d. Modulation

307. What is meant by the term modulation?

a. The squelching of a signal until a critical signal-to-noise

ratio is reached

b. Carrier rejection through phase nulling

c. A linear amplification mode

d. A mixing process whereby information is imposed upon a

carrier

308. What is a balanced modulator?

a. An FM modulator that produces balance deviation

b. A modulator that produces a DSBSC signal

c. A modulator that produces a SSBSC signal

d. A modulator that produces a full carrier signal

309. What is a reactance modulator?

a. A circuit that acts as a variable resistance or capacitance

to produce FM signals

b. A circuit that acts as a variable resistance or capacitance

to produce AM signals

c. A circuit that acts as a variable inductance or capacitance

to produce FM signals

d. A circuit that acts as a variable inductance or capacitance

to produce AM signals

310. How can an SSB phone signal be generated?

a. By dividing product detector with a DSB signal

b. By using a reactance modulator followed by a mixer

c. By using a loop modulator followed by a mixer

d. By using a balanced modulator followed by a filter

311. How can a DSB phone signal be generated?

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

filter

b. By using a balanced modulator followed by a filter

c. By detuning a Hartley oscillator

d. By modulating the plate voltage of a class C amplifier

312. First symbol in the designation of

radio signals emission which refers to use of an

unmodulated carrier.

a. J

b. N

c. H

d. A

313. One of the following is a communications filter

generally used in the transceiver of a single sideband

generator.

a. Lowpass filter

b. Crystal filter

c. Bandpass filter

d. Mechanical filter

314. What is the modulation index for an AM signal having

Vmax and Vmin of 2.6 and 0.29, respectively?

a. 0.799

b. 0.111

c. 0.894

d. 0.639

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

15-kHz intelligence signal?

a. 7.5 kHz

b. 15 kHz

c. 30 kHz

d. 60 kHz

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

is unmodulated, determine the total radiated power when it

is modulated at 30%

a. 10.45 watts

b. 10750 watts

c. 11.5 kilowatts

d. 10450 watts

317. Which of the following waveform characteristics

determines the wavelength of a sine wave?

a. Phase

b. Amplitude

c. Period

d. Phase angle

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

between the deviation of a frequency modulated signal and

the modulating frequency?

a. FM compressibility

b. Quieting index

c. Modulation index

d. Percentage of modulation

319. Which frequency band is the standard AM radio

broadcast?

a. HF

b. UHF

c. MF

d. VHF

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

also known as

a. Pilot carrier system

b. Independent sideband emission

c. Lincompex

d. Vestigial sideband transmission

321. What are the two general categories of methods for

generating emission F3E?

a. The only way to produce an emission F3E signal is with

reactance modulator on the oscillator

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

balanced modulator on the oscillator

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

balanced modulator on the audio amplifier

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

reactance modulator on the final amplifier

322. 100% modulation in AM means a corresponding

increase in total power by ____.

a. 25%

b. 75%

c. 100%

d. 50%

323. How does the SSB transmitter output power normally

expressed?

a. Average power

b. In terms of peak envelope power

c. In terms of peak-to-peak power

d. Peak power

324. Determine from the following the common use of DSB

in broadcast and telecommunications

a. Satellite communication

b. FM/TV stereo

c. Two-way communications

d. Telephone systems

325. What is the source of sidebands in frequency

modulation?

a. Oscillator

b. Baseband frequency

c. Mixer

d. Carrier harmonics

326. What is the source of sidebands in frequency

modulated voice?

a. A3F

b. A3J

c. F3E

d. J3E

327. The third symbol in the designation of radio emission

under the ITU refers to

a. Type of modulation of the main carrier

b. Nature of signals

c. Type of information to be transmitted

d. Nature of multiplexing

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

transmitted as an SSB signal, what would be the total

power transmitted?

a. 500 W

b. 1000 W

c. 1500 W

d. 2000 W

329. This circuit has the function of demodulating the

frequency-modulated signal. It is a

a. Automatic gain control

b. Automatic frequency control

c. Envelope detector

d. Foster-Seeley discriminator

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

whose carrier power is 50 watts. The unmodulated current

is 2 A while the modulated current is 2.4 A.

a. 22 W

b. 33 W

c. 11 W

d. 44 W

331. The method of generating FM used by broadcasting

station is

a. Direct

b. All of these

c. Indirect

d. Insertion

332. Deviation ratio of an FM transmitter is the ratio of the

a. Maximum frequency swing to the highest modulating

frequency

b. Operating frequency of the assigned frequency

c. Frequency swing to the modulating frequency

d. Highest modulating frequency to the minimum frequency

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

1.5 kHz and 2.5 kHz with modulations of 20 percent and 80

percent respectively. Calculate the effective modulation

index.

a. 0.7776

b. 0.6

c. 0.8246

d. 1.0

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

for its original value of 10 W. To what value must the carrier

be reduced?

a. 1 milliwatt

b. 10 microwatts

c. 0.10 milliwatts

d. 0.01 microwatts

335. Which circuit in the AM transmitter does the frequency

translation?

a. Synthesizer

b. Modulator

c. Mixer

d. Booster

336. A phase modulator has Kp= 2 rad/V. What RMS

voltage of a sine wave would cause a peak phase deviation

of 30 degrees?

a. 0.158 V

b. 0.185 V

c. 0.518 V

d. 0.815 V

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

a. Variable capacitor oscillator

b. Varactor-capacitor oscillator

c. Voltage-controlled oscillator

d. VHF control oscillator

338. Diagonal clipping in envelope detection will result in

a. Distortion

b. Diagonal clipping

c. Phase reversal

d. Amplitude damage

339. An AM transmitter supplies a 10 kW of carrier power to

a 50 ohm load. It operates at a carrier frequency of 1.2 MHz

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

RMS voltage of the signal.

a. 825 W

b. 262. 61 V

c. 1166.7 V

d. 825 V

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

transmitting station whose carrier power is 1200W and a

modulation of 95%?

a. 270.75 W

b. 900 watts

c. 1.8 kW

d. 542 W

341. Which among the following is capable of generating

frequency conversion?

a. Balanced modulator

b. Low-Q LC Circuit

c. Transmitter

d. Circulator

342. The most commonly used AM demodulator

a. Envelope detector

b. PLL

c. Mixer

d. Balanced modulator

343. Which is a disadvantage of direct FM generation?

a. The need for an AFC circuit

b. The need for an AGC circuit

c. Two balanced modulators are used

d. The use of Class A amplifier which is very inefficient

344. Frequency division is useful in the implementation of

a/an

a. AM demodulator

b. Frequency synthesizer

c. AGC circuit

d. FM demodulator

345. A particular synthesizer which contains only a single

crystal is

a. Direct

b. Crystal-modulated

c. Indirect

d. Exact

346. Type of emission most affected by selective fading

a. FM and DSB AM

b. SSB and TV

c. CCTV and CW

d. CW and SSB

347. Which major element will not be found in every

superheterodyne receiver?

a. RF amplifier

b. IF amplifier

c. LO

d. Mixer

348. A system uses a deviation of 100 kHz and a

modulating frequency of 15 kHz. What is the approximate

bandwidth?

a. 115 kHz

b. 230 kHz

c. 170 kHz

d. 340 kHz

349. A quadrature detector requires that

a. The inputs are coherent

b. Four gates are provided

c. The inputs are in phase

d. The inputs are similar

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

whose carrier power is 300 W, with 80 percent modulation?

a. 396 W

b. Zero

c. 48 W

d. 96 W

351. Determine the resonant frequency of a

series combination of a 0.001 microfarad capacitor and a 2

– milihenry inductor.

a. 112.5 kHz

b. 35.59 kHz

c. 1125.4 MHz

d. 3.26 MHz

352. Which of the following is not a typical part of every

radio transmitter?

a. Carrier oscillator

b. Driver amplifier

c. Mixer

d. Final power amplifier

353. What is the approximate magnitude of the impedance

of a parallel RLC circuit at resonance?

a. Approximately equal to the circuit resistance

b. Approximately equal to XL

c. Low, as compared to the circuit resistance

d. Approximately equal to XC

354. What are the three major oscillator circuits often used

in radio equipment?

a. Taft, Pierce, and negative feedback

b. Colpitts, Hartley, and Taft

c. Taft, Hartley, and Pierce

d. Colpitts, Hartley, and Pierce

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

Hartley oscillator?

a. Through a neutralizing capacitor

b. Through a capacitive divider

c. Through a link coupling

d. Through a tapped coil

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

Colpitts oscillator?

a. Through a tapped coil

b. Trough link coupling

c. Through a capacitive divider

d. Through a neutralizing capacitor

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

Pierce oscillator?

a. Through a tapped coil

b. Trough link coupling

c. Through a capacitive divider

d. Through a neutralizing capacitor

358. Which of the three major oscillator circuits used in

radio equipment utilizes a quartz crystal?

a. Negative feedback

b. Hartley

c. Colpitts

d. Pierce

359. What is the piezoelectric effect?

a. Mechanical vibration of a crystal by the application of a

voltage

b. Mechanical deformation of a crystal by the application of

a magnetic field

c. The generation of electrical energy by the application of

light

d. Reversed conduction states when pn-junction is exposed

to light

360. What is the major advantage of a Pierce oscillator?

a. It is easy to neutralize

b. It doesn’t require an LC tank circuit

c. It can be tuned over a wide range

d. It has high output power

361. Which type of oscillator circuit is commonly used in a

VFO?

a. Pierce

b. Colpitts

c. Hartley

d. Negative feedback

362. Why is the Colpitts oscillator circuit commonly used in

a VFO?

a. The frequency is a linear function of the load impedance

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

c. It is stable

d. It has high output power

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

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

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

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

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

364. For reasonably efficient operation of a transistor

amplifier, what should be the load resistance be with 12

volts at the collector and a 5 watts power output?

a. 100.3 ohms

b. 14.4 ohms

c. 10.3 ohms

d. 144 ohms

365. What order of Q is required by a tank circuit sufficient

to reduce harmonics to an acceptable level?

a. Approximately 120

b. Approximately 12

c. Approximately 1200

d. Approximately 1.2

366. What is the flywheel effect?

a. The continued motion of a radio wave through space

when the transmitter is turned off

b. The back and forth oscillation of electrons in an LC circuit

c. The use of a capacitor in a power supply to filter rectified

AC

d. The transmission of a radio signal to a distant station by

several hops through the ionosphere

367. How can parasitic oscillations be eliminated from a

power amplifier?

a. By tuning for maximum SWR

b. By tuning for maximum power output

c. By neutralization

d. By tuning the output

368. If the spectrum is shifted in frequency with no other

changes, this is known as

a. Frequency multiplication

b. Sideband movement

c. Baseband orientation

d. Frequency translation

369. A device which is capable of causing frequency

translation

a. High-Q tank circuit

b. Balanced modulator

c. Low-Q tank circuit

d. IF strip

370. If the frequency of each component in a signal

spectrum is increased by the same fixed amount, this is

known as

a. Up conversion

b. Demodulation

c. Frequency translation

d. Both a and c

371. A particular amplifier is designed to be a frequency

doubler. If the input signal frequency is 15.4 MHz, a circuit

in the output will be tuned to

a. 7.7 MHz

b. 15.4 MHz

c. 30.8 MHz

d. 61.6 MHz

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

be

a. Active

b. Passive

c. Linear

d. Nonlinear

373. A particular amplifier circuit used for frequency

coupling is known as

a. Push-push

b. Push-pull

c. Pull-push

d. Pull-pull

374. Frequency division is useful in the implementation of a

a. AM demodulation

b. Frequency synthesizer

c. FM demodulator

d. AGC circuit

375. Indirect frequency synthesizers will include

a. phase-locked loop

b. voltage-controlled oscillators

c. multiple bank crystals

d. both A and B

376. A particular frequency synthesizer contains only a

single crystal. What words describe this synthesizer?

a. Crystal modulated

b. Inexact

c. Indirect

d. Deficient

377. A recognizable feature of a CW transmitter is

a. Keyed transmitter

b. Power amplification

c. Frequency generation

d. All of the above

378. The term “pulling” refers to

a. The change of the crystal oscillator frequency by loading

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

c. Loading on the transmitter caused by the antenna

connection

d. Reduction of the power supply terminal voltage as the

transmitter is keyed

379. An AM broadcast transmitter in the multi-kilowatt

operating range will have what form of final amplifier?

a. Solid-state devices

b. Vacuum tubes

c. Travelling wave tubes

d. Both a and b

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

a. Automatic gain control limiter

b. Compression amplifier

c. Loudness controller

d. All of the above

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

transmitter?

a. AM

b. SSB

c. CW

d. FM

382. A circuit that isolates the carrier oscillator from load

changes is called a

a. Final amplifier

b. Driver amplifier

c. Linear amplifier

d. Buffer amplifier

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

network is known as

a. Signal bias

b. Self-bias

c. Fixed external bias

d. Threshold bias

384. Collector current in a class C amplifier is

a. Sine wave

b. Half-sine wave

c. Pulse

d. Square wave

385. Neutralizing is the process of

a. Cancelling the effect of internal device capacitance

b. Bypassing undesired alternating current

c. Reducing gain

d. Eliminating harmonics

386. In an AM transmitter, a clipper circuit eliminates

a. Harmonics

b. Splatter

c. Over-deviation

d. Excessive gain

387. The final power amplifier in an FM transmitter usually

operates class

a. A

b. B

c. C

d. D

388. A transistor RF power amplifier can be tuned for

a. Minimum IC in the next stage

b. Zero signal in the next stage

c. Minimum IC in the same stage

d. Maximum IC in the same stage

389. The purpose of a balanced modulator circuit is to

eliminate the

a. Carrier

b. Upper sideband

c. Lower sideband

d. Baseband signal

390. A frequency multiplier circuit

a. Operates class A

b. Is tuned to a harmonic of the input signal

c. Needs parasitic oscillations

d. Is usually pulse modulated

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

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

has a Q of 40. Find the bandwidth using the optimum

coupling factor.

a. 10.192 kHz

b. 15.288 kHz

c. 152.88 kHz

d. 101.92 kHz

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

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

the tuning voltage necessary for the circuit to resonate at

twice its resonant frequency with no tuning voltage applied.

a. 5 V

b. 2.5 V

c. 7.5 V

d. 4.25 V

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

frequency of 14 MHz. As the frequency of the reference

input is gradually raised from zero, the loop locks at 12

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

capture range.

a. 4 MHz

b. 2 MHz

c. 12 MHz

d. 8 MHz

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

transmitter with multipliers is composed of a pair of triplers

and a doubler is 198 MHz, what frequency should the

oscillator operate?

a. 11 MHz

b. 33 MHz

c. 22 MHz

d. 66 MHz

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

frequency of 14 MHz. As the frequency of the reference

input is gradually raised from zero, the loop locks at 12

MHZ and comes out of lock again at 18 MHz. Calculate the

lock range.

a. 4 MHz

b. 2 MHz

c. 12 MHz

d. 8 MHz

396. A crystal oscillator is accurate within 0.0005%. How far

off frequency could its output be at 37 MHz?

a. 135 Hz

b. 150 Hz

c. 185 Hz

d. 224 Hz

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

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

the modulating amplifier for 100% modulation?

a. 6.25 W

b. 7.14 W

c. 12.5 W

d. 14.3 W

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

collector current of 2 A. The modulation transformer has a

turns ratio of 4:1. What is the load impedance seen by the

audio amplifier?

a. 96 ohms

b. 128 ohms

c. 6 ohms

d. 8 ohms

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

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

the transistor power dissipation with 100% modulation.

a. 93. 75 W

b. 120 W

c. 64 W

d. 56. 25 W

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

carrier power when operating from a 25 V supply. What is

the required load impedance as seen from the collector?

a. 15.625 ohms

b. 22.5 ohms

c. 11.25 ohms

d. 31.25 ohms

401. What is receiver desensitizing?

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

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

c. A reduction in receiver sensitivity because of a strong

signal on a nearby frequency

d. A reduction in receiver sensitivity is turned down

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

receiver gain caused by the signals of a nearby station

transmitting in the same frequency band?

a. Desensitizing

b. Quieting

c. Cross-modulation interference

d. Squelch gain roll back

403. What is the term used to refer to a reduction in

receiver sensitivity caused by unwanted high-

level adjacent channel signals?

a. Intermodulation distortion

b. Quieting

c. Desensitizing

d. Overloading

404. How can receiver desensitizing be reduced?

a. Ensure good RF shielding between the transmitter and

receiver

b. Increase the transmitter audio gain

c. Decrease the receiver squelch gain

d. Increase the receiver bandwidth

405. What is cross-modulation interference?

a. Interference between two transmitters of different

modulation types

b. Interference caused by audio rectification in the receiver

preamp

c. Decrease the receiver squelch gain

d. Modulation from an unwanted signal is heard in addition

to the desired signal

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

the signals from a very strong station are super imposed on

the other signals being received?

a. Intermodulation distortion

b. Cross-modulation interference

c. Receiver quieting

d. Capture effect

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

a. By installing a filter at the receiver

b. By using a better antenna

c. By increasing the receiver’s RF gain while decreasing the

AF gain

d. By adjusting the passband tuning

408. What is the result of cross-modulation?

a. Decrease in modulation level of transmitted signals

b. Receiver quieting

c. The modulation of an unwanted signal is heard on the

desired signal

d. Inverted sidebands in the final stage of the amplifier

409. What is the capture effect?

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

receiver

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

receiver

c. The loudest signal received is the only demodulated

signal

d. The weakest signal received is the only demodulated

signal

410. What is a product detector?

a. A detector that provides local oscillator for input to the

mixer

b. A detector that amplifies and narrows

the bandpass frequencies

c. A detector that uses mixing process with a locally

generated carrier

d. A detector used to detect cross-modulation products

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

blockage of one FM-phone signal?

a. Desensitization

b. Cross-modulation interference

c. Capture effect

d. Frequency discrimination

412. What is the process of detection?

a. The process of masking out the intelligence on a

received carrier to make an S-meter operational

b. The recovery of intelligence from the modulated RF

signal

c. The modulation of a carrier

d. The mixing of noise with the received signal

413. What is the principle of detection in a diode detector?

a. Rectification and filtering of RF

b. Breakdown of the Zener voltage

c. Mixing with the noise in the transition region of the diode

d. The change of reactance in the diode with respect to

frequency

414. How are FM phone signals detected?

a. By a balanced modulator

b. By a frequency discriminator

c. By a product detector

d. By a phase splitter

415. What is the mixing process?

a. The elimination of noise in a wideband receiver by phase

comparison

b. The elimination of noise in a wideband receiver by phase

differentiation

c. Distortion caused by aural propagation

d. The combination of the two signals to produce sum and

difference frequencies

416. What is a frequency discriminator?

a. A circuit for detecting FM signals

b. A circuit for filtering two closely adjacent signals

c. An automatic band switching circuit

d. An FM generator

417. What are the principal frequencies which appear at the

output of a mixer circuit?

a. Two and four times the original frequency

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

frequencies

c. The original frequencies and the sum and difference

frequencies

d. 1.414 and 0.707 times the frequency

418. What occurs in a receiver when an excessive amount

of signal energy reaches the mixer circuit?

a. Spurious mixer products are generated

b. Mixer blanking occurs

c. Automatic limiting occurs

d. A beat frequency is generated

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

stage of a receiver?

a. As much as possible short of self oscillation

b. Sufficient gain to allow weak signals to overcome noise

generated in the first mixer

c. Sufficient gain to keep weak signals below the noise of

the first mixer stage

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

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

have sufficient gain to allow weak signals to overcome

noise generated in the first mixer stage?

a. To prevent the sum and difference frequencies from

being generated

b. To prevent bleed-through of the desired signal

c. To prevent generation of spurious mixer products

d. To prevent bleed-trough of the local oscillator

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

receiver?

a. To provide most of the receiver gain

b. To vary the receiver image rejection by utilizing the AGC

c. To improve the receiver’s noise figure

d. To develop the AGC voltage

422. What is an IF amplifier stage?

a. A fixed-tuned passband amplifier

b. A receiver demodulator

c. A receiver filter

d. A buffer oscillator

423. What factors should be considered when selecting an

intermediate frequency?

a. A cross-modulation distortion and interference

b. Interference to other services

c. Image rejection and selectivity

d. Noise figure and distortion

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

stage in a receiver?

a. A noise figure performance

b. Tune out cross-modulation distortion

c. Dynamic response

d. Selectivity

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

stage in a receiver?

a. Dynamic response

b. Gain

c. Noise figure performance

d. Bypass undesired signals

426. Which stage of a receiver primarily establishes its

noise figure?

a. The audio stage

b. The IF stage

c. The RF stage

d. The local oscillator

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

communications receiver?

a. The level of noise entering the receiver from the antenna

b. The relative strength of a strength of a received signal 3

kHz removed from the carrier frequency

c. The level of noise generated in the front end and

succeeding stages of a receiver

d. The ability of a receiver to reject unwanted signals at

frequencies close to the desired one

428. The ability of a communications receiver to perform

well in the presence of strong signals outside the band of

interest is indicated by what parameter?

a. Noise figure

b. Blocking dynamic range

c. Signal-to-noise ratio

d. Audio output

429. What type problems are caused by poor dynamic

range in a communications receiver?

a. Cross-modulation of the desired signal and

desensitization from strong adjacent signals

b. Oscillator instability requiring frequent returning, and loss

of ability to recover the opposite sideband should it be

transmitted

c. Cross-modulation of the desired signal and insufficient

audio power to operate the speaker

d. Oscillator instability and severe audio distortion of all but

the strongest signal received signals

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

tolerable receiver input signal and the minimum discernible

signal?

a. Intermodulation distortion

b. Noise floor

c. Noise figure

d. Dynamic range

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

bandwidth is used in the IF stage of a receiver?

a. Undesired signals will reach the audio stage

b. Output-offset overshoot

c. Cross-modulation distortion

d. Filter ringing

432. How can selectivity be achieved in the front and

circuitry of a communications receiver?

a. By using an audio filter

b. By using a pre-selector

c. By using an additional RF amplifier stage

d. By using an additional IF amplifier stage

433. How should the filter bandwidth of a receiver IF

section compare with the bandwidth of a received signal?

a. Filter bandwidth should be slightly greater than the

received signal bandwidth

b. Filter bandwidth should be approximately half the

received signal bandwidth

c. Filter bandwidth should be approximately two times the

received signal bandwidth

d. Filter bandwidth should be approximately four times the

received signal bandwidth

434. How can receiver selectivity be achieved in the IF

circuitry of a communications receiver?

a. Incorporate a means of varying the supply voltage to the

local oscillator circuitry

b. Replace the standard JFET mixer with a bipolar

transistor followed by a capacitor of the proper value

c. Remove AGC action from the IF stage and confine it to

the audio stage only

d. Incorporate a high-Q filter

435. A receiver has a sensitivity of 0.6 microvolts and a

blocking dynamic range of 60 dB. What is the strongest

signal that can be present along with a 0.6 microvolt signal

without blocking taking place

a. 600 millivolts

b. 600 microvolts

c. 300 millivolts

d. 300 mircovolts

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

kHz. Calculate the image rejection in dB assuming that the

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

a. 19.28 dB

b. 39.65 dB

c. 38.57 dB

d. 19.83 dB

437. A receiver has two uncoupled tuned circuits before the

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

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

injection. Calculate the image rejection ratio.

a. 23.69 dB

b. 58.66 dB

c. 29.33 dB

d. 11.84 dB

438. What oscillator frequency is needed to heterodyne 626

kHz up to 3.58 MHz?

a. 2.954 MHz

b. 4.832 MHz

c. 4.210 MHz

d. 2.328 MHz

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

bandwidth in the IF section of a receiver?

a. Output-offset overshoot

b. Undesired signals will reach the audio stage

c. Thermal noise distortion

d. Filter ringing

440. What is the limiting condition for sensitivity in a

communications receiver?

a. the noise floor of the receiver

b. the power supply output ripple

c. the two-tone intermodulation distorting

d. the input impedance to the detector

441. What parameter must be selected when designing an

audio filter using an op-amp?

a. Bandwidth characteristics

b. Desired current gain

c. Temperature coefficient

d. Output-offset overshoot

442. What two factors determine the sensitivity of a

receiver?

a. Dynamic range and third-order intercept

b. Cost and availability

c. Intermodulation distortion and dynamic range

d. Bandwidth and noise figure

443. How can unwanted ringing and audio instability be

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

a. Restrict both gain and Q

b. Restrict gain, but increase Q

c. Restrict Q but increase gain

d. Increase both gain and Q

444. What is meant by the dynamic range of a

communications receiver?

a. The number of kHz between the lowest and the highest

frequency to which the receiver can be tuned

b. The maximum possible undistorted audio output of the

receiver referenced to one milliwatt

c. The ratio between the minimum discernible signal and

the largest tolerable signal without causing audible

distortion products

d. The difference between the lowest frequency signal

detectable without moving the tuning knob

445. Where is the noise which primarily determines the

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

receiver generated?

a. In the receiver front end

b. Man-made noise

c. In the atmosphere

d. In the ionosphere

446. An AM receiver uses a diode detector for

demodulation. This enables it satisfactorily to receive

a. Single-sideband, suppressed carrier (J3E)

b. Single-sideband, reduced carrier (R3E)

c. ISB(B8E)

d. Single-sideband, full carrier (H3E)

447. Three-point tracking is achieved with

a. Variable selectivity

b. The padder capacitor

c. Double spotting

d. Double conversion

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

have poor

a. Blocking

b. Double-spotting

c. Diversity reception

d. Sensitivity

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

receiver, this will have the effect of

a. Gain variation over the frequency coverage range

b. Insufficient gain and selectivity

c. Inadequate selectivity at high frequencies

d. Instability

450. The image frequency of a superheterodyne receiver

a. Is created within the receiver itself

b. Is due to insufficient adjacent channel rejection

c. Is not rejected by the IF tuned circuits

d. Is independent of the frequency to which receiver is

tuned

451. The process of impressing a low frequency

information signals onto a high-frequency carrier signal is

called _____.

a. demodulation

b. oscillation

c. modulation

d. amplification

452. A silicon varactor diode exhibits a capacitance of

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

pF capacitor and a 200-uH inductor, calculate the range of

resonant frequency as the diode varies through a reverse

bias of 3 to 15V.

a. 679 kHz to 2.13 MHz

b. 966 kHz to 1.15 MHz

c. 355 kHz to 3.12 MHz

d. 143 kHz to 4.53 MHz

453. A process where the received signal is transformed

into its original form.

a. demodulation

b. damping

c. amplification

d. oscillation

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

high frequency carrier signal in proportion with the

instantaneous value of the modulating signal.

a. frequency modulation

b. digital modulation

c. phase modulation

d. analog modulation

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

a. carrier

b. upper sideband

c. lower sideband

d. modulating signal

456. Amplitude modulation is the same as

a. linear mixing

b. analog multiplexing

c. signal summation

d. multiplexing

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

______.

a. sidebands

b. modulating signal

c. envelope

d. carrier signal

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

is supplied by

a. tuned circuit

b. transformer

c. capacitor

d. inductor

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

change present in an AM waveform.

a. coefficient of modulation

b. modulation index

c. depth of modulation

d. any of these

460. When the modulation index in an AM wave is greater

than one it will cause _______.

a. buck-shot

b. splatter

c. overmodulation

d. any of these

461. The ideal value of modulation index in AM.

a. 1

b. 0

c. 100

d. infinity

462. When the amplitude of the information in an AM

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

modulation index?

a. 1

b. 0

c. 100

d. infinity

463. Amplitude modulation can be produced by

a. having the carrier vary a resistance

b. having the modulating signal vary a capacitance

c. varying the carrier frequency

d. varying the gain of the amplifier

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

transmitted power is equal to ________.

a. one of the sidebands

b. carrier

c. double sidebands

d. an AM wave

465. When the modulation takes place prior to the output

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

collector of the output transistor in a transistorized

transmitter, this is called ______.

a. high-level modulation

b. low-level modulation

c. zero-modulation

d. constant modulation

466. A circuit that monitors the received signal level and

sends a signal back to the RF and IF amplifiers to adjust

their gain automatically.

a. automatic phase control

b. automatic gain control

c. automatic frequency control

d. automatic volume control

467. When the modulation takes place in the final element

of the final stage where the carrier signal is at its maximum

amplitude, it is called _____.

a. constant modulation

b. zero-modulation

c. low-level modulation

d. high-level modulation

468. If a superheterodyne receiver is tuned to a desired

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

operating at 1300kHz, what would be the frequency of an

incoming signal that would possibly cause image

reception?

a. 1600 kHz

b. 2300 kHz

c. 1250 kHz

d. 3420 kHz

469. When modulation requires a much higher amplitude

modulating signal to achieve a reasonable percent

modulation, this is called

a. high-level modulation

b. low-level modulation

c. zero-modulation

d. constant modulation

470. Amplitude modulators that vary the carrier amplitude

with the modulating signal by passing it through an

attenuator work on principle of

a. rectification

b. resonance

c. variable resistance

d. absorption

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

source signal to a usable level while producing minimum

nonlinear distortion adding as little thermal noise as

possible.

a. power amplifier

b. non-linear amplifier

c. buffer amplifier

d. preamplifier

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

linear amplifier which is used to isolate the oscillator from

the high-power amplifiers.

a. power amplifier

b. bandpass filter

c. signal driver

d. buffer amplifier

473. With high-level transmitters, which of the following is

not a primary function of the modulator circuit?

a. it provides the capacity necessary for modulation to

occur

b. it serves as a final amplifier

c. it serves as a frequency up-converter

d. it serves as a mixer

474. It is a form of amplitude distortion introduced

when positive and negative alternations in the AM

modulated signal are not equal.

a. phase shift

b. carrier shift

c. amplitude variations

d. frequency shift

475. A carrier is simultaneously modulated by two sine

waves with modulation indices of 0.3 and 0.4, the total

modulation index

a. is 1

b. cannot be calculated unless the phase relations are

known

c. is 0.5

d. is 0.7

476. The component used to produce AM AT very high

frequencies is a

a. varactor

b. thermistor

c. cavity resonator

d. PIN diode

477. It is also known as upward modulation

a. carrier shift

b. amplitude variations

c. frequency shift

d. phase shift

478. Also known as downward modulation

a. carrier shift

b. amplitude variations

c. frequency shift

d. phase shift

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

two separate information sources modulate the same

carrier frequency at the same time without interfering with

each other.

a. QPSK

b. QUAM

c. PSK

d. FSK

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

0.55nW sensitivity. Determine the maximum allowable input

signal.

a. 59 mW

b. 69 mW

c. 79 mW

d. 88 mW

481. The information sources modulate the same carrier

after it has been separated into two carrier signals are at 90

degrees out of phase with each other.

a. QPSK

b. QUAM

c. PSK

d. FSK

482. Demodulating quadrature AM signal requires a carrier

recovery circuit to reproduce the original carrier frequency

and phase and two balanced modulators to actually

demodulate the signals. This is called ________.

a. asynchronous detection

b. quadrature demodulation

c. synchronous detection

d. quadrature detection

483. Quadrature amplitude modulation is also known as

________.

a. phase division multiplexing

b. phase division modulation

c. phase amplitude multiplexing

d. phase angle modulation

484. Amplitude modulation generated at a very low voltage

or power amplitude is known as

a. high-level modulation

b. low-level modulation

c. collector modulation

d. minimum modulation

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

called the receiver front end.

a. mixer

b. RF section

c. local oscillator

d. IF stage

486. In an SSB transmitter, one is most likely to find a

a. class C audio amplifier

b. tuned modulator

c. class B RF amplifier

d. class A RF output amplifier

487. The section of the receiver than down-converts the

received RF frequencies to intermediate frequencies.

a. RF section

b. local oscillator

c. power amplifier

d. mixer

488. The circuit that demodulates the AM wave and

converts it to the original information signal.

a. power amplifier

b. local oscillator

c. detector

d. IF section

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

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

100 percent modulation is

a. 24 V

b. 48 V

c. 96 V

d. 120 V

490. What signals might feed into an FM broadcast station

audio control console?

a. microphones

b. turntables

c. remote lines

d. any of these

491. The noise reduction ratio achieved by reducing the

bandwidth is called

a. dynamic range

b. noise figure

c. bandwidth efficiency

d. bandwidth improvement

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

at the input to the receiver and still produce a usable

demodulated information signal.

a. selectivity

b. sensitivity

c. Q-factor

d. bandwidth

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

a. m = 0

b. m = 1

c. m < 1

d. m > 1

494. Why are limiters used in FM receivers?

a. provide better noise performance

b. clip noise peaks

c. prevent overdrive of discriminators

d. any of these

495. Why are limiters used in FM transmitters?

a. clip noise peaks

b. prevent overdrive of discriminators

c. prevent overdeviation

d. any of these

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

minimum input level necessary to discern the signal and the

input level that will overdrive the receiver and produce

distortion.

a. dynamic range

b. noise figure

c. bandwidth efficiency

d. bandwidth improvement

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

useful.

a. dynamic range

b. noise figure

c. bandwidth efficiency

d. bandwidth improvement

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

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

a. 1-dB compression point

b. 1-dB threshold point

c. 1-dB shoot-off point

d. 1-dB pinch-off point

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

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

replica of the original source information.

a. sensitivity

b. threshold

c. selectivity

d. fidelity

500. A SSB signal generated around a 200-kHz carrier.

Before filtering, the upper and lower sidebands are

separated by 200 Hz. Calculate the filter Q required to

obtain 40-dB suppression.

a. 1500

b. 1900

c. 2500

d. 2000

301. DSB

302. PIN diode

303. D

304. Sidebands

305. 3

306. Demodulation

307. mixing process whereby information is imposed upon a carrier

308. A modulator that produces a DSBSC signal

309. A circuit that acts as a variable inductance or capacitance to

produce FM signals

310. By using a balanced modulator followed by a filter

311. By modulating the plate voltage of a class C amplifier

312. N

313. Mechanical filter

314. 0.799

315. 30 kHz

316. 10450 watts

317. Period

318. Modulation index

319. MF

320. Independent sideband emission

321. The only way to produce an emission F3E signal is with

reactance modulator on the oscillator

322. 50%

323. In terms of peak envelope power

324. FM/TV stereo

325. Baseband frequency

326. F3E

327. Type of information to be transmitted

328. 500 W

329. Foster-Seeley discriminator

330. 11 W

331. Indirect

332. Maximum frequency swing to the highest modulating

frequency

333. 0.8246

334. 0.10 milliwatts

335. Mixer

336. 0.185 V

337. Voltage-controlled oscillator

338. Distortion

339. 825 V

340. 542 W

341. Balanced modulator

342. Envelope detector

343. The need for an AFC circuit

344. Frequency synthesizer

345. Indirect

346. FM and DSB AM

347. RF amplifier

348. 230 kHz

349. The inputs are coherent

350. 48 W

351. 112.5 kHz

352. Mixer

353. Approximately equal to the circuit resistance

354. Colpitts, Hartley, and Pierce

355. Through a tapped coil

356. Through a capacitive divider

357. Through a neutralizing capacitor

358. Colpitts

359. Mechanical vibration of a crystal by the application of a

voltage

360. It doesn’t require an LC tank circuit

361. Colpitts

362. It is stable

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

364. 14.4 ohms

365. Approximately 12

366. The back and forth oscillation of electrons in an LC circuit

367. By neutralization

368. Frequency translation

369. Balanced modulator

370. Both a and c

371. 30.8 MHz

372. Nonlinear

373. Push-push

374. Frequency synthesizer

375. both A and B

376. Indirect

377. All of the above

378. The change of the crystal oscillator frequency by loading

379. Both a and b

380. All of the above

381. SSB

382. Buffer amplifier

383. Signal bias

384. Pulse

385. Cancelling the effect of internal device capacitance

386. Splatter

387. Class C

388. Minimum IC in the same stage

389. Carrier

390. Is tuned to a harmonic of the input signal

391. 15.288 kHz

392. 7.5 V

393. 4 MHz

394. 11 MHz

395. 8 MHz

396. 185 Hz

397. 6.25 W

398. 128 ohms

399. 56. 25 W

400. 15.625 ohms

401. A reduction in receiver sensitivity because of a strong signal

on a nearby frequency

402. Desensitizing

403. Quieting

404. Ensure good RF shielding between the transmitter and

receiver

405. Modulation from an unwanted signal is heard in addition to the

desired signal

406. Cross-modulation interference

407. By installing a filter at the receiver

408. The modulation of an unwanted signal is heard on the desired

signal

409. The loudest signal received is the only demodulated signal

410. A detector that uses mixing process with a locally generated

carrier

411. Capture effect

412. The recovery of intelligence from the modulated RF signal

413. Rectification and filtering of RF

414. By a frequency discriminator

415. The combination of the two signals to produce sum and

difference frequencies

416. A circuit for detecting FM signals

417. The original frequencies and the sum and difference

frequencies

418. Spurious mixer products are generated

419. Sufficient gain to allow weak signals to overcome noise

generated in the first mixer

420. To prevent generation of spurious mixer products

421. To improve the receiver’s noise figure

422. A fixed-tuned passband amplifier

423. A cross-modulation distortion and interference

424. Selectivity

425. Gain

426. The RF stage

427. The level of noise generated in the front end and succeeding

stages of a receiver

428. Blocking dynamic range

429. Cross-modulation of the desired signal and desensitization

from strong adjacent signals

430. Dynamic range

431. Filter ringing

432. By using a pre-selector

433. Filter bandwidth should be slightly greater than the received

signal bandwidth

434. Incorporate a high-Q filter

435. 600 microvolts

436. 38.57 dB

437. 29.33 dB

438. 2.954 MHz

439. Undesired signals will reach the audio stage

440. the noise floor of the receiver

441. Bandwidth characteristics

442. Bandwidth and noise figure

443. Restrict both gain and Q

444. The ratio between the minimum discernible signal and the

largest tolerable signal without causing audible distortion products

445. In the receiver front end

446. Single-sideband, full carrier (H3E)

447. The padder capacitor

448. Blocking

449. Insufficient gain and selectivity

450. Is not rejected by the IF tuned circuits

451. modulation

452. 966 kHz to 1.15 MHz

453. demodulation

454. analog modulation

455. carrier

456. linear mixing

457. envelope

458. tuned circuit

459. any of these

460. any of these

461. 1

462. 0

463. varying the gain of the amplifier

464. carrier

465. low-level modulation

466. automatic gain control

467. high-level modulation

468. 1600 kHz

469. high-level modulation

470. variable resistance

471. preamplifier

472. buffer amplifier

473. it serves as a mixer

474. carrier shift

475. is 0.5

476. PIN diode

477. carrier shift

478. carrier shift

479. QUAM

480. 69 mW

481. QUAM

482. quadrature detection

483. phase division multiplexing

484. low-level modulation

485. RF section

486. class A RF output amplifier

487. mixer

488. detector

489. 96 V

490. any of these

491. bandwidth improvement

492. sensitivity

493. m = 1

494. any of these

495. prevent overdeviation

496. dynamic range

497. dynamic range

498. 1-dB compression point

499. fidelity

500. 2500