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INTRODUCTORY TOPICS

1.. Which part of the sinewave expression cannot be varied in

accordance with the low-frequency intelligence to create a

modulated signal?

a)Phase

b)Frequency

c)Time

d)Amplitude

2. Communication systems are most often categorized by what

characteristic?

a) Modulation frequency

b) Carrier frequency

c) Transmission distance

d) Information transmitted

3. Voltage gain in decibels is

a) 10 ln V2/V1

b) 10 logV2/V1

c) 20 lnV2/V1

d) 20 log V2/V1

4. Which expression indicates a measurement using a 1-W

reference?

a) dBm

b) dB1

c) dBW

d) dB(W)

5. An amplifier operating over a 2-Mhz bandwidth has a 75 ohm

input resistance. If it is operating at 22° C and has a voltage gain of 300, the noise produced at the output of this amplifier would be

approximately

a) 128uV

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b) 7.33pV

c) 1.56uV

d) 469uV d)

6. Which of the following is not an example of external noise?

a) Fluorescent light

b) Solar emission

c) Resistor noise

d) Lightning

7. An amplifier's output signal has 25 mV p-p of desired signal

mixed in with 45 uV rms of undesired noise. The load impedance

is 50 ohm. What is the amplifier's output S/N level in dB?

a) 22.9 dB

b) 54.9 dB

c) 45.9 dB

d) 51.9 dB

8.Why does a 5-kHz square wave require a greater bandwidth than

a 2-kHz sinewave?

a) The square wave has a larger frequency than the sine wave.

b) The square wave has an infinite number of harmonics,

whereas the sinewave has only one.

c) The square wave is much easier to cover by noise.

d) The square wave must also include an offset (dc) voltage, whereas the sinewave does not.

9. The relationship between information and bandwidth is called

a) Information theory

b) Fourier analysis

c) FFT

d) Hartley's law

10. Aliasing can be defined as errors occurring when

a) The input frequency exceeds the sample rate.

b) The bandwidth is less than the input frequency.

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c) The type of modulation has been incorrectly identified.

d) The sampling signal has been incorrectly identified.

11.Which of the following does not hold true for a parallel

resonant circuit?

a) At the resonant frequency the impedance of the circuit is a minimum.

b) If Q>10, the resonant frequency is the same as it would be if it were a series.

c) It is commonly referred to as a tank circuit.

d) At the resonant frequency, the circuit draws minimum current

from the constant-voltage source.

12. The oscillator design that uses a third capacitor in the tank circuit for swamping out the effect of the transistor's internal

capacitances is the

a) Hartley design

b) Clapp design

c) Colpitts design

d) Crystal design

13.The ability of a crystal to oscillate at its resonant frequency is

due to

a) The flywheel effect

b) Barkhausen criteria

c) The piezoelectric effect

d) Frequency synthesis

14. The Barkhausen criteria has to do with

a) Receiver noise

b) Fourier analysis

c) Oscillation

d) Troubleshooting

15.Which of the following can be called a troubleshooting plan?

a) Symptoms as clues to faulty stages

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b) Signal tracing and signal injection

c) Voltage and resistance measure Substitution

d) All the above

Fill in the blank

16. When discussing the radio-frequency spectrum, the

abbreviation VF means ________ frequency.

a) video

b) volume

c) voice

d) variable

17. A 600 ohm audio system has a 4-V output. That represents a ________-dBm (600) signal.

a) 28.52

b) 14.26

c) 7.13

d) 0.713

18. A 0-dBW level is defined as ________ with respect to a 1-W reference.

a) 1 W

b) 0 W

c) 10 W

d) 0.1W

19. Two other terms for thermal noise are ________ and

________.

a) Johnson; pink

b) Watkins; pink

c) Johnson; white

d) Watkins; white

20.. The S/N ratio at the input of a device to its output S/N is called

the ________ ________.

a) noise figure

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b) electrical noise

c) excess noise

d) noise ratio

21 The ________ noise-measurement technique allows

reasonably accurate readings using an oscilloscope.

a) internal

b) tangential

c) external

d) phosphur

22. `Representing a square wave using five harmonics introduces

________ distortion than using three harmonics.

a) Less

b) More

c) unlimited

d) the same

23. A circuit that has a balance between inductive and capacitive

reactance is said to be in ________.

a) Sync

b) Hysteresis

c) Resonance

d) trouble

24. A filter has a Q of ________ when its loss is 3 dB, fr = 3

MHz, and its BW is 60 kHz.

a) 5 0

b) .02

c) 0.2

d) 50

25 A crystal oscillator specified at 100 kHz with 20 ppm accuracy

should never exceed ________ kHz.

a) 99.998

b) 100.00

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c) 2 99.98

d) 100.02

26. In a modulated system, the low-frequency intelligence signal is not called the

a) Modulating signal

b) Information signal

c) Modulating wave

d) Carrier

27. A 7.0-Mhz carrier is modulated by a voice signal that has

three frequency components of 100 Hz, 200 Hz, and 300 Hz. What three frequencies comprise the lower sideband?

a) 6.9997 Mhz, 6.9998 Mhz, and 6.9999 Mhz

b) 100 Hz, 200 Hz, and 300 Hz

c) 6.9999 Mhz, 7.0000 Mhz, and 7.0001 Mhz

d) 7.0001 Mhz, 7.0002 Mhz, and 7.0003 Mhz

28. The total output power of an AM transmitter is measured to be 850 W. What is the total output sideband power if it has a

percent modulation of 100%?

a) 425 W b) 850 W

c) 283.3 W

d) 141.65 W

29. A 100-kHz carrier is modulated by a 20-Hz – 2kHz signal.

The upper sideband is

a) 102 kHz

b) 100.02 kHz to 102 kHz

c) 101 kHz

d) 100.002 kHz to 102 kHz

30. One full revolution of a phasor generates which percentage of

a full sinewave?

a) 25%

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b) 50%

c) 100%

d) 200%

31. An AM waveform at maximum is 100 V p-p and at minimum

is 40 V p-p. The modulation percentage is

a) 250%

b) 40%

c) 25%

d) 37.5%

32. A transmitter having a 900-W carrier transmits 1188 W when

modulated with a single sinewave. If the carrier is simultaneously modulated with another sinewave at 60% modulation, calculate the

total transmitted power.

a) 1084 W

b) 1170 W

c) 1350 W

d) 1224 W

33. Low-level modulation is

a) The most economic approach for low-power transmitters.

b) Characterized by the use of "linear" power amplifiers to amplify the AM signal.

c) Characterized by having the carrier and the intelligence signals mix at low power levels

d) All the above.

34. The main advantage of a high-level modulation system

compared to a low-level system is that it

a) Allows more efficient amplification.

b) Allows use of low-powered intelligence signal.

c) Provides higher modulation percentage.

d) Is more economical.

35. What is the purpose of a buffer amplifier stage in a

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transmitter?

a) It prevents transmitters from producing spurious frequencies

in the output signals.

b) It provides power amplification with high efficiency.

c) Its high input impedance prevents oscillators from drifting off frequency.

d) It amplifies audio frequencies before modulation occurs.

36. The purpose of an antenna coupler is to

a) Match the output impedance of the transmitter with the antenna's impedance to provide maximum power transfer.

b) Allow the transmitter to be connected to several antennas at

the same time.

c) Filter out the carrier frequency from the transmitter's AM

output signal.

d) Cause the transmitter to operate at more than one carrier

frequency at the same time.

37. The main reason for using a dummy antenna is to

a) Prevent damage to output circuits.

b) Minimize damage to the regular antenna.

c) Prevent overmodulation.

d) Prevent undesired transmissions.

38. A spectrum analyzer is

a) An instrument that displays amplitude versus frequency on a

CRT.

b) Often used to determine if a transmitter's output signal is free from any spurious signals.

c) Can be thought of as a radio receiver with broad frequency range.

d) All the above.

39. The strategy for repair of electronic equipment includes the

following.

a) Verify that a problem exists.

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b) Isolate the defective stage. Isolate the defective component.

c) Replace the defective component and hot check.

d) All the above.

40. A technique that helps you understand how a carrier and

sideband combine to form the AM waveform is

a) The tangential method.

b) Phasor representation.

c) Keying.

d) None of the above.

FILL IN THE BLANK

41. Direct transmission of intelligence signals without modulation

would cause ________ problems.

a) interference

b) static

c) spurs

d) keying

42. A nonlinear device is characterized by a nonlinear output

versus ________ relationship.

a) noise

b) gain

c) bandwidth

d) input

43. In AM, overmodulation creates frequencies ________ a

station's normal allocated range.

a) within

b) outside

c) below

d) around

44. In AM, 100% modulation indicates that ________% of the

total transmitted power is in the sidebands.

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a) 50

b) 33.33

c) 25

d) 100

45. An AM transmitter transmits 200 W when modulated at 40%.

The power in the lower sideband is ________ W.

a) 7.41

b) 14.82

c) 92.59

d) 85.18

46. The type of transistor modulator (base, emitter, or collector) is determined by where the ________ is input.

a) carrier

b) intelligence

c) dc

d) ac

47. The use of a PIN-diode modulator is prevalent at ________ frequencies.

a) Audio

b) elf

c) microwave

d) infrared

48. In a newly constructed transmitter, it is common to go

through a(n) ________ procedure to get it on the air.

a) Examination

b) Quality

c) Keying

d) Tune-up

49. When generating the trapezoid pattern, the intelligence signal

is applied to the ________ input of the oscilloscope.

a) Vertical

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b) horizontal

c) Z

d) audio

50. When troubleshooting a high-powered transmitter, the most

important consideration is ________.

a) Output

b) frequency

c) safety

d) noise

51. The main problem with the TRF design is

a) Lack of selectivity in receiving all AM stations

b) Poor demodulation of an AM station

c) Frustration in tuning to receive more than one station

d) Lack of sensitivity in receiving all AM stations

52. The sensitivity of a receiver has to do with its ability to

a) Withstand shock

b) Receive one station versus another

c) Receive weak stations

d) All the above

53. When the input to an ideal nonlinear device is an AM

waveform consisting of a carrier and its sidebands, the output of nonlinear mixing produces the original intelligence because

a) The intelligence signal is one of its inputs.

b) A dc component is also produced.

c) The difference between the carrier and its sidebands is the

original intelligence frequency.

d) The intelligence frequencies are the upper and the lower

sideband frequencies.

54. An AM signal having a carrier frequency of 940 kHz is to be

mixed with a local oscillator output signal in order to produce an intermediate frequency of 455 kHz. At what should the L.O.

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frequency be set?

a) 455 kHz

b) 1395 kHz

c) 910 kHz

d) 1850 kHz

55.Diodes that have been specially fabricated to produce a

capacitance that varies inversely proportional to the amount of reverse bias are called

a) Varactor diodes

b) Varicap diodes

c) VVC diodes

d) All the above

56. The image frequency for a standard broadcast receiver using a 455-kHz IF and tuned to a station at 680 kHz would be

a) 1135 kHz

b) 225 kHz

c) 1590 kHz

d) 1815 kHz

57. Double conversion is used to overcome the problem of

a) Image frequency

b) Tracking Diagonal

c) clipping

d) Poor sensitivity

58.An auxiliary AGC diode

a) Reduces selectivity

b) Increases sensitivity

c) Decreases sensitivity

d) All the above

59. Which of the following would occur in a receiver not having AGC?

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a) The speaker output level would drastically change while tuning from a weak signal to a strong signal.

b) Local stations would easily produce distorted signals in the speaker.

c) There would be a constant need to readjust the volume control as the weather and ionosphere change.

d) All the above

60. The only roadblock to having a complete receiver

manufactured on an integrated circuit is

a) Tuned circuits and volume controls

b) Cost

c) Phase-locked loops

d) Ceramic filters

61. The decibel difference between the largest tolerable receiver input signal and its sensitivity is called

a) The decibel power gain of the receiver

b) Automatic gain control (AGC)

c) The dynamic range of the receiver

d) The IF amplifier gain

62. The simplest AM detector is the

a) Synchronous detector

b) Product detector

c) Heterodyne detector

d) Diode detector

63. Tracking in a superhet receiver is accomplished using a

a) Trimmer capacitor

b) Padder capacitor

c) Varicap diode

d) a and b

64. If no stations are picked up on the lower half of the AM band, the likely problem is

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a) Low RF gain

b) Poor AGC operation

c) IF selectivity

d) LO tracking

65. If no sound is heard from a receiver, the most likely problem

area is the

a) Power supply

b) RF section

c) Audio amplifier

d) AGC diode

FILL IN THE BLANK

66. A TRF receiver includes three stages: the RF, ________, and

audio amplifier.

a) IF

b) detector

c) trimmer

d) mixer

67. The extent to which a receiver can differentiate between the

desired signal and others is termed its ________.

a) selectivity

b) sensitivity

c) figure-of-merit

d) gain

68. AM detection requires a nonlinear device because a linear

device ________ create difference frequencies.

a) helps

b) only

c) doesn't

d) sometimes

69. A synchronous detector is able to produce ________

distortion outputs.

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a) zero

b) low

c) high

d) infinite

70. Another name for the ________ is the first detector.

a) mixer

b) VCO

c) oscillator

d) diode

71. The padder and trimmer capacitors are used to facilitate

________ in a superhet receiver.

a) Alignment

b) Sensitivity

c) Images

d) tracking

72. Image-frequency problems are reduced by using ________

conversion systems.

a) single

b) double

c) backward

d) autodyne

73. The gain of a bipolar transistor can be controlled by varying

the ________ emitter current.

a) Residule

b) ac

c) envelope

d) dc

74. The use of a(n) ________ AGC diode reduces receiver gain for

very large signals.

a) P-I-N

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b) varicap

c) auxiliary

d) point-contact

75. A quick test to determine if the audio amplifier is working is

to touch a screwdriver to the center terminal of the ________ ________.

a) volume control

b) power transistor

c) trimmer capacitor

d) padder capacitor

76. An SSB signal with a maximum level of 200 V p-p into a 50 ohm load results in a PEP rating of

a) 200 W

b) 50 W

c) 100 W

d) 800 W

77. State the chief advantage(s) of a standard SSB system.

a) Maximum signal range with minimum transmitted power

b) Easy carrier reinsertion

c) Elimination of carrier interference

d) a and c

78. The noise advantage of SSB over AM is

a) 3–5 dB

b) 5–7 dB

c) 8–10 dB

d) 10–12 dB

79. What is the difference between a balanced modulator and a regular modulator?

a) There is no carrier produced in the output of a balanced

modulator.

b) In a balanced modulator, there is 180º phase shift between

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the upper and lower sidebands.

c) In a balanced modulator, only one sideband is produced.

d) In a balanced modulator, harmonics of the sidebands are

suppressed.

80. In a balanced-ring modulator, the carrier suppression is accomplished by

a) A dual-gate FET having symmetry

b) Center-tapped transformers causing canceling magnetic fields

c) The nonlinearity of the diodes that are used

d) Symmetrical differential amplifier stages

81. Which cannot be used successfully to convert DSB-SC to SSB?

a) Crystal filter

b) Ceramic filter

c) Mechanical filter

d) Tank circuit

82. Another term for ripple amplitude for a ceramic filter is

a) The shape factor

b) The peak-to-valley ratio

c) The insertion loss

d) The quality factor

83. Which of the following is not an advantage of the phase

method over the filter method in producing SSB?

a) The design of the 90º phase-shift network for the intelligence frequencies is simple.

b) Lower intelligence frequencies can be economically used, because a high-Q filter is not necessary.

c) Intermediate balanced modulators are not necessary, because high-Q filters are not needed.

d) It is easier to switch from one sideband to the other.

84. Once an SSB signal has been generated, it must be amplified

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by

a) A nonlinear amplifier to conserve bandwidth

b) A nonlinear amplifier to conserve energy

c) A linear amplifier to conserve bandwidth

d) A linear amplifier to avoid distortion

85. The advantages provided by carrier elimination in SSB do

not apply to transmission of

a) Code

b) Music

c) Noise

d) All the above

86. Provide the approximate "outside-of-passband" attenuation of

a Butterworth filter.

a) 3-dB slope per octave

b) 3-dB slope per decade

c) 6-dB slope per octave

d) 6-dB slope per decade

87. An SSB receiver recreates the original intelligence signal by

a) Mixing the USB with LSB signals and filtering out the resulting different frequencies

b) Filtering out the difference between either sideband and the

internally generated carrier signal

c) Filtering out the harmonics of the received sideband signal

frequencies

d) Amplifying the dc term produced by mixing action

88. Common types of balanced modulators include

a) Ring modulator

b) Phase modulator

c) Lattice modulator

d) All the above

89. Describe the oscilloscope waveform of an SSB transmitter's

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balanced modulator if it exhibits carrier leakthrough.

a) Trapezoidal wave

b) Sinewave

c) FM wave

d) AM wave

90. The two-tone test is used to

a) Test carrier suppression

b) Test filter ripple

c) Test amplifier linearity

d) None of the above

FILL IN THE BLANK

91. The most obvious problem with SSB is accurate ________

reinsertion at the receiver.

a) audio

b) modulator

c) carrier

d) compandor

92. Twin-sideband suppressed-carrier systems are often used in

________ applications.

a) industrial

b) military

c) amateur

d) commercial

93. A balanced-ring modulator connects from ________ diodes

in a ring configuration.

a) P-I-N

b) Varicap

c) point-contact

d) matched

94. The balanced-ring modulator provides a ________ output.

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a) suppressed

b) DSB

c) ISB

d) VCO

95. The high-Q filter in an SSB transmitter is used to eliminate a

________.

a) sideband

b) spur

c) frequency

d) harmonic

96. A ________ filter offers the highest-possible Q for use in SSB transmitters.

a) mechanical

b) SAW

c) crystal

d) ceramic

97. The two common methods of generating SSB are the filter and ________ methods.

a) Butterworth

b) Phase

c) independent

d) envelope

98. A balanced modulator used to recover the intelligence in an

SSB signal is called a ________ detector.

a) Diode

b) envelope

c) product

d) divisor

99. The BFO is a ________-frequency oscillator.

a) backward

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b) balanced

c) bandpass

d) beat

100. A commonly used test to determine amplifier linearity is the

________ test.

a) two-tone

b) tangential

c) harmonic

d) THD

101. Angle modulation includes the following types of modulation:

a) FM

b) PM

c) AM

d) All the above

e) a and b

102. The amount of frequency increase and decrease around the

center frequency in an FM signal is called the

a) Index of modulation

b) Frequency deviation

c) Phase deviation

d) Bandwidth of the FM signal

103. The amount of frequency deviation is dependent on the

intelligence frequency in

a) An FM signal

b) A PM signal

c) Both FM and PM signals

d) Neither FM nor PM signals

104. An FM signal has an intelligence frequency of 2 kHz and a

maximum deviation of 10 kHz. If its carrier frequency is set at

162.4 Mhz, what is its index of modulation?

a) 10

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b) 5

c) 2

d) 20

105. The amount an FM carrier frequency deviates for a given

modulating input voltage level is called the

a) Frequency deviation

b) Index of modulation

c) Deviation constant

d) Deviation ratio

106. Standard FM broadcast stations use a maximum bandwidth

of

a) 150 kHz

b) 200 kHz

c) 75 kHz

d) 15 kHz

107. Carson's rule is used to approximate the necessary

a) Frequency deviation

b) Bandwidth

c) Capture ratio

d) Modulation index

108. An FM transmitter has an output power of 500 W when it is not modulated. When intelligence is added, its modulation index is

2.0. What is its output power with a modulation index of 2.0?

a) 250 W

b) 500 W

c) 1000 W

d) 2000 W

109. Another way to describe the modulation index is using the

a) Deviation ratio

b) Deviation constant

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c) Capture ratio

d) Maximum deviation

110. The inherent ability of FM to minimize the effect of

undesired signals operating at the same or nearly the same

frequency as the desired station is known as the

a) Capture effect

b) Signal-to-noise ratio

c) Noise figure

d) Bessel function

111. In a Crosby FM transmitter, an FM signal having a center

frequency of 2.04 Mhz and a deviation of 69 Hz is passed through

four cascaded frequency multiplier stages: two triplers, one doubler, and one quadrupler. What type of signal appears at the

output of the last multiplier stage?

a) Center frequency of 2.04 Mhz and deviation of 4.96 kHz

b) Center frequency of 146.88 Mhz and deviation of 4.96 kHz

c) Center frequency of 2.04 Mhz and deviation of 69 Hz

d) Center frequency of 146.88 Mhz and deviation of 69 Hz

112. The circuitry used to increase the operating frequency of a

transmitter up to a specified value is called the

a) Multiplier

b) Expander

c) Pump chain

d) All the above

113. The purpose of the matrix network in a stereo FM broadcast transmitter is to

a) Mix the 38-kHz pilot carrier with the L – R audio

b) Convert the L and R channels to L + R and L – R channels

c) Separate the left channel from the right channel

d) Modulate the L + R and L – R signals with the carrier signal

114. An FM signal has an intelligence frequency of 5 kHz and a

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maximum deviation of 25 kHz. Its index of modulation is

a) 125

b) 0.2

c) 5

d) 6

115. Frequency multipliers

a) Are used to multiply the frequency of the carrier signal of an

FM signal

b) Consist of a class C amplifier followed by a tank circuit that filters out a single harmonic

c) Are used to multiply the frequency deviation of an FM signal

d) All the above

FILL IN THE BLANK

116. In FM receivers, the ________ extracts the intelligence from a

high-frequency carrier.

a) discriminator

b) multiplexer

c) phase-detector

d) matrix

117. Cross-modulation is similar to ________ distortion.

a) THD

b) harmonic

c) inter modulation

d) noise

118. The difference between a receiver's maximum and minimum

tolerable input signal is called its ________ range.

a) threshold

b) useful

c) working

d) dynamic

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119. A ________ is a circuit whose output is a constant amplitude for inputs above a critical value.

a) clipper

b) limiter

c) compandor

d) rail-to-rail

120. The discriminator is also called a ________.

a) limiter

b) oscillator

c) detector

d) mixer

121. The ________ detector lends itself to integration on a single

chip.

a) ratio

b) PLL

c) quadrature

d) slope

122. A PLL uses ________ feedback to maintain a constant output

frequency.

a) Positive

b) Negative

c) audio

d) AGC

123. A stereo demodulator contains a(n) ________-kHz

subcarrier.

a) 19

b) 38

c) 15

d) 67

124. Wobbling the IF frequency can help determine if the limiter,

discriminator, and ________ circuits are operating correctly.

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a) mixer

b) RF

c) oscillator

d) audio

125. The filter in a quadrature detector is usually a ________ type.

a) ceramic

b) crystal

c) Butterworth

d) Hartley

126. .A difference between AM and FM receiver block diagrams

is that the FM version includes a

a) Limiter

b) Discriminator

c) Deemphasis network

d) All the above

127. An FM receiver rarely works satisfactorily without an RF

amplifier because

a) FM receivers typically work with smaller input signal levels

due to their noise characteristics.

b) FM receivers have a narrower bandwidth.

c) FM receivers do not have very much gain in their IF

amplifier stages.

d) FM receivers need RF amplifier stages to be able to decode

stereo signals.

128. A certain FM receiver provides a voltage gain of 113 dB prior to its limiter. The limiter's quieting voltage is 400 mV. Its

sensitivity is approximately

a) 2uV

b) 1uV

c) 0.9uV

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d) 0.7uV

129. The use of dual-gate MOSFETs in RF amplifier stages

a) Offers increased dynamic range over those of JFETs

b) Produces higher-frequency responses than do JFETs

c) Produces higher values of voltage gain than do JFETs

d) Is not compatible with AGC

130. The Foster-Seely detector design is superior to the ratio

detector in that it

a) Does not respond to any undesired amplitude variations

b) Also provides an output AGC signal

c) Offers superior linear response to wideband FM deviations

d) Does not need a limiter stage

131. Local oscillator reradiation refers to radiation through the

a) Receiver's wiring

b) IF transformer

c) Antenna

d) All the above

132. Which is not one of the three stages in which a PLL can be operated?

a) Free-running

b) Capture

c) Locked/tracking

d) Searching

133. A PLL is set up so that its VCO free-runs at 8.9 Mhz. The VCO does not change frequency unless its input is within +/-75

kHz of 8.9 Mhz. After it does lock, the input frequency can be

adjusted within +/-120 kHz of 8.9 Mhz without having the PLL start to free-run again. The capture range of the PLL is

a) 75 kHz

b) 120 kHz

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c) 150 kHz

d) 240 kHz

134. Slope detection is seldom used due to

a) Nonlinearity

b) Attenuation

c) Complexity

d) All the above

135. In an FM stereo receiver, what is the purpose of the 23–53-

kHz filter?

a) To filter out the SCA signal at the output of the discriminator

b) To filter out the L – R signal at the output of the

discriminator

c) To filter out the L + R signal at the output of the

discriminator

d) To produce separate L and R signals from the L + R and L –

signals

136. A dual audio amplifier is rated to provide 65 dB of channel separation. If the right channel has 4 W of output power, how

much of this power could be due to the left channel intelligence?

a) 4 W

b) 79 nW

c) 1.26 uW

d) 2.25 mW

137. The hold-in range for a PLL concerns the

a) Range of frequencies in which it will remain locked

b) Allowable range of dc voltage

c) Allowable range of ac input voltage

d) Satisfactory range of operating temperatures

138. The input signal into a PLL is at the

a) VCO

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b) Low-pass filter

c) Comparator

d) Phase detector

139. The square-law relationship of the FETs input versus output

a) Allows for greater sensitivity in an FM receiver

b) Provides improved noise performance

c) Reduces shot noise

d) Minimizes cross-modulation

140. When troubleshooting a stereo demodulator, the input signal

should be about

a) 10uV rms

b) 100uVrms

c) 1 mV rms

d) 100 mV rms

141. Why are image frequencies somewhat less of a problem in FM receivers than they are in SSB or AM receivers?

a) SSB uses less bandwidth than does FM.

b) FM signals have a capture effect characteristic.

c) FM mixer stages are square-law devices.

d) FM receivers do not use the super heterodyne design.

142. The tuned circuits prior to the mixer in a super heterodyne receiver are called the

a) Front end

b) Tuner

c) Pre selector

d) All the above

143. The signal-strength meter that shows the relative signal-strength level is called the ________ .

a) S meter

b) Signal meter

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c) Strength meter

d) All the above

144. An AM broadcast receiver has two identical tuned circuits

with a Q of 50 prior to the IF stage. The IF frequency is 460 kHz

and the receiver is tuned to a station on 550 kHz. The image-frequency rejection is

a) 41 dB

b) 36.2 dB

c) 72.4 dB

d) 82 dB

145. An AGC that causes a step reduction in receiver gain at some

arbitrarily high value of received signal in order to prevent overloading the receiver is known as

a) Arbitrary AGC

b) Auxiliary AGC

c) Delayed AGC

d) Variable AGC

146. Up-conversion offers the following advantage(s):

a) Less expensive filters

b) Good image-frequency rejection

c) Minimized tuning range for the LO

d) b and c

147. The range over which the input to a receiver or amplifier

provides a usable output is called the

a) Level of acceptability

b) Dynamic range

c) Degree of usefulness

d) Specified input

148. A receiver has a 30-dB noise figure, a 1.5 Mhz bandwidth, a

6-dBm third intercept point, and a 3-dB signal-to-noise ratio. Its

sensitivity is

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a) –94 dB

b) –82.2 dB

c) –79.2 dB

d) –81 dB

149. Two-modulus dividers are used in the synthesis of

frequencies into the VHF band due to

a) Its ability to work at practical power consumptions

b) Its ability to work at practical speeds

c) The insufficient speed and power of the basic programmable divider designs

d) All the above

150. The disadvantage of direct digital synthesizers (DDS) over

analog frequency synthesizers is

a) Its complexity and cost

b) Its limited maximum output frequency

c) Its higher phase noise

d) All the above

151. The G.E. Phoenix radio is an example of

a) An HF amateur transceiver using AM and SSB modulation

modes

b) A VHF commercial transceiver using the FM modulation

mode and a channel guard function

c) A military transceiver using all modes on HF frequencies

d) A cellular telephone transceiver

152. The type of radio transmission that uses pseudorandomly

switched frequency or time transmissions is known as

a) Synthesizing

b) Facsimile

c) Spread spectrum

d) Compression

153. The acronym CDMA refers to ________.

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a) Carrier-division multiple-access systems

b) Capture-division multiple-access systems

c) Code-division multiple-access systems

d) Channel-division multiple-access systems

154. A typical problem encountered when troubleshooting a

frequency synthesizer is

a) A small frequency error

b) A large frequency error

c) No output

d) All the above

155. A transceiver is

a) A transmitter that can be tuned to several bands of

frequencies

b) A transmitter that transmits digital data

c) A receiver that receives digital data

d) A transmitter and receiver in a single package

156. Communication equipment that includes a transmitter and receiver is commonly called a ________.

a) transponder

b) transceiver

c) two-way

d) preselector

157. Techniques for minimizing image frequencies include double

conversion and ________-conversion.

a) Down

b) up

c) crystal

d) converter

158. Unwanted signals are often referred to as ________

interference.

a) Noise

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b) Selector

c) squelch

d) electromagnetic

159. The ________ system cuts off a receiver's output during

transmission lulls.

a) squelch

b) AGC

c) quieting

d) muting

160. The ________ intercept is another name for the third-order

intercept point.

a) Noise

b) Distortion

c) input

d) IM

161. The output of the PLL's phase comparator is called the

________ voltage.

a) error

b) phase

c) feedback

d) correction

162. In DDS, the NCO contains the ________ accumulator and

ROM look-up table.

a) Phase

b) Frequency

c) Error

d) synthesis

163. Channel guard causes a very specific ________ frequency to

be encoded onto the carrier together with the intelligence.

a) correction

b) audio

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c) RF

d) pseudorandom

164. Pseudorandom implies a sequence that can be ________ but

has the properties of randomness.

a) decoded

b) detected

c) minimized

d) recreated

165. The ________ switch is responsible for switching the antenna between the transmitter and receiver in a transceiver.

a) S

b) guard

c) TR

d) hit