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Chapter 1. Introductory Topics

1. Which part of the sinewave expression cannot be varied inaccordance with the low-frequency intelligence to create amodulated signal?

a. Phaseb. Frequencyc. Time

d. Amplitude

2. Communication systems are most often categorized by whatcharacteristic?

a. Modulation frequencyb. Carrier frequencyc. Transmission distanced. Information transmitted

3 Voltage gain in decibels is

a. 10 ln

b. 10 log

c. 20 ln

d. 20 log

4 Which expression indicates a measurement using a 1-Wreference

a. dBm(1)b. dB1c. dBWd. dB(W)

5 An amplifier operating over a 2-Mhz bandwidth has a 75 inputresistance. If it is operating at 22° C and

has a voltage gain of 300, the noise produced at the output ofthis amplifier would be approximately

a.

b.

c.

d.

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

a. Fluorescent lightb. Solar emissionc. Resistor noised. Lightning

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

mixed in with 45 V rms of undesired noise. The loadimpedance is 50 . What is the amplifier's output S/N level indB?

a. 22.9 dB

b. 54.9 dBc. 45.9 dBd. 51.9 dB

8 Why does a 5-kHz square wave require a greater bandwidththan a 2-kHz sinewave?

a. The square wave has a larger frequency than the sinewave. 

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 theoryb. Fourier analysisc. FFTd. 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.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 parallelresonant circuit?

a. At the resonant frequency the impedance of the circuit is aminimum.

b. If Q>10, the resonant frequency is the same as it would be ifit 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 tankcircuit for swamping out the effect of the

transistor's internal capacitances is the

a. Hartley designb. Clapp designc. Colpitts designd. Crystal design

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

a. The flywheel effectb. Barkhausen criteriac. The piezoelectric effectd. Frequency synthesis

14 The Barkhausen criteria has to do with

a. Receiver noiseb. Fourier analysisc. Oscillation

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  d. Troubleshooting

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

a. Symptoms as clues to faulty stagesb. Signal tracing and signal injectionc. Voltage and resistance measured. Substitution

e. All the above

Chapter 2. Amplitude Modulation: Transmission

1. In a modulated system, the low-frequency intelligence signal isnot called the

a. Modulating signalb. Information signalc. Modulating waved. Carrier

2. A 7.0-Mhz carrier is modulated by a voice signal that has threefrequency components of 100 Hz,

200 Hz, and 300 Hz. What three frequencies comprise thelower sideband?

a. 6.9997 Mhz, 6.9998 Mhz, and 6.9999 Mhzb. 100 Hz, 200 Hz, and 300 Hzc. 6.9999 Mhz, 7.0000 Mhz, and 7.0001 Mhzd. 7.0001 Mhz, 7.0002 Mhz, and 7.0003 Mhz

3. The total output power of an AM transmitter is measured to be850 W. What is the total output sideband

power if it has a percent modulation of 100%?

a. 425 Wb. 850 Wc. 283.3 Wd. 141.65 W

4. A 100-kHz carrier is modulated by a 20-Hz  – 2kHz signal. Theupper sideband is

a. 102 kHzb. 100.02 kHz to 102 kHzc. 101 kHz

d. 100.002 kHz to 102 kHz

5. One full revolution of a phasor generates which percentage ofa full sinewave?

a. 25%b. 50%c. 100%d. 200%

6. An AM waveform at maximum is 100 V p-p and at minimum is40 V p-p. The modulation percentage is

a. 250%b. 40%c. 25%d. 37.5%

7. A transmitter having a 900-W carrier transmits 1188 W whenmodulated with a single sinewave. If the carrier is simultaneouslymodulated with another sinewave at 60% modulation, calculatethe total transmitted power.

a. 1084 Wb. 1170 Wc. 1350 W

d. 1224 W

8. 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 levelsd. All the above.

9. The main advantage of a high-level modulation systemcompared 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.

10. What is the purpose of a buffer amplifier stage in atransmitter?

a. It prevents transmitters from producing spuriousfrequencies 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.

11. The purpose of an antenna coupler is to

a. Match the output impedance of the transmitter with theantenna'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.

12. 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.

13. A spectrum analyzer is

a. An instrument that displays amplitude versus frequency ona CRT.

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

c. Can be thought of as a radio receiver with broad frequencyrange.

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  d. All the above.

14.The strategy for repair of electronic equipment includes thefollowing.

a. Verify that a problem exists.b. Isolate the defective stage.c. Isolate the defective component.

d. Replace the defective component and hot check.e. All the above.

15. A technique that helps you understand how a carrier andsideband combine to form the AM waveform

is

a. The tangential method.b. Phasor representation.c. Keying.d. None of the above.

Chapter 3: Amplitude Modulation: Reception

1. The main problem with the TRF design is

a. Lack of selectivity in receiving all AM stationsb. Poor demodulation of an AM stationc. Frustration in tuning to receive more than one stationd. Lack of sensitivity in receiving all AM stations

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

a. Withstand shock

b. Receive one station versus anotherc. Receive weak stationsd. All the above

3. When the input to an ideal nonlinear device is an AMwaveform consisting of a carrier and its

sidebands, the output of nonlinear mixing produces theoriginal 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 lowersideband frequencies.

4. An AM signal having a carrier frequency of 940 kHz is to bemixed with a local oscillator output signal in

order to produce an intermediate frequency of 455 kHz. Atwhat should the L.O. frequency be set?

a. 455 kHzb. 1395 kHzc. 910 kHzd. 1850 kHz

5. Diodes that have been specially fabricated to produce acapacitance that varies inversely proportional tothe amount of reverse bias are called

a. Varactor diodes

b. Varicap diodesc. VVC diodesd. All the above

6. The image frequency for a standard broadcast receiver usinga 455-kHz IF and tuned to a station at 680

kHz would be

a. 1135 kHz

b. 225 kHzc. 1590 kHzd. 1815 kHz

7. Double conversion is used to overcome the problem of

a. Image frequencyb. Trackingc. Diagonal clippingd. Poor sensitivity

8. An auxiliary AGC diode

a. Reduces selectivityb. Increases sensitivityc. Decreases sensitivityd. All the above

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

a. The speaker output level would drastically change whiletuning from a weak signal to a strong signal.

b. Local stations would easily produce distorted signals in thespeaker.

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

d. All the above

10. The only roadblock to having a complete receivermanufactured on an integrated circuit is

a. Tuned circuits and volume controlsb. Costc. Phase-locked loopsd. Ceramic filters

11. The decibel difference between the largest tolerable receiverinput signal and its sensitivity is called

a. The decibel power gain of the receiverb. Automatic gain control (AGC)c. The dynamic range of the receiverd. The IF amplifier gain

12. The simplest AM detector is the

a. Synchronous detectorb. Product detectorc. Heterodyne detectord. Diode detector

13. Tracking in a superhet receiver is accomplished using a

a. Trimmer capacitor

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  b. Padder capacitorc. Varicap dioded. a and be. All the above

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

a. Low RF gain

b. Poor AGC operationc. IF selectivityd. LO tracking

15. If no sound is heard from a receiver, the most likely problemarea is the

a. Power supplyb. RF sectionc. Audio amplifierd. AGC diode

Chapter 4: Single-Sideband Communications

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

a. 200 Wb. 50 Wc. 100 Wd. 800 W

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

a. Maximum signal range with minimum transmitted powerb. Easy carrier reinsertionc. Elimination of carrier interferenced. a and c

3. The noise advantage of SSB over AM is

a. 3 –5 dBb. 5 –7 dBc. 8 –10 dBd. 10 –12 dB

4. What is the difference between a balanced modulator and a

regular modulator?

a. There is no carrier produced in the output of a balancedmodulator.

b. In a balanced modulator, there is 180º phase shift betweenthe 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.

5. In a balanced-ring modulator, the carrier suppression isaccomplished by

a. A dual-gate FET having symmetryb. Center-tapped transformers causing canceling magneticfields

c. The nonlinearity of the diodes that are usedd. Symmetrical differential amplifier stages

6.Which cannot be used successfully to convert DSB-SC toSSB?

a. Crystal filterb. Ceramic filterc. Mechanical filterd. Tank circuit

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

a. The shape factorb. The peak-to-valley ratioc. The insertion lossd. The quality factor

8. Which of the following is not an advantage of the phasemethod over the filter method in producing SSB?

a. The design of the 90º phase-shift network for theintelligence 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.

9. Once an SSB signal has been generated, it must be amplifiedby

a. A nonlinear amplifier to conserve bandwidthb. A nonlinear amplifier to conserve energyc. A linear amplifier to conserve bandwidthd. A linear amplifier to avoid distortion

10. The advantages provided by carrier elimination in SSB donot apply to transmission of

a. Codeb. Musicc. Noised. All the above

11. Provide the approximate "outside-of-passband" attenuationof a Butterworth filter.

a. 3-dB slope per octaveb. 3-dB slope per decadec. 6-dB slope per octaved. 6-dB slope per decade

12. An SSB receiver recreates the original intelligence signal by

a. Mixing the USB with LSB signals and filtering out theresulting different frequencies

b. Filtering out the difference between either sideband and theinternally generated carrier signal

c. Filtering out the harmonics of the received sideband signalfrequencies

d. Amplifying the dc term produced by mixing action

13. Common types of balanced modulators include

a. Ring modulator

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  b. Phase modulatorc. Lattice modulatord. All the above

14. Describe the oscilloscope waveform of an SSB transmitter'sbalanced modulator if it exhibits carrier

leakthrough.

a. Trapezoidal waveb. Sinewavec. FM waved. AM wave

15. The two-tone test is used to

a. Test carrier suppressionb. Test filter ripplec. Test amplifier linearityd. None of the above

Chapter 5: Frequency Modulation Transmission

1 Angle modulation includes the following types of modulation:

a. FM

b. PM

c. AM

d. All the above

e. a and b

2 The amount of frequency increase and decrease around thecenter frequency in an FM signal is called the

a. Index of modulation

b. Frequency deviation

c. Phase deviation

d. Bandwidth of the FM signal

3 The amount of frequency deviation is dependent on theintelligence frequency in

a. An FM signal

b. A PM signal

c. Both FM and PM signals

d. Neither FM nor PM signals

4 An FM signal has an intelligence frequency of 2 kHz and amaximum deviation of 10 kHz. If its carrier frequency is set at162.4 Mhz, what is its index of modulation?

a. 10

b. 5

c. 2d. 20

5 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

6 Standard FM broadcast stations use a maximum bandwidthof

a. 150 kHz

b. 200 kHz

c. 75 kHz

d. 15 kHz

7 Carson's rule is used to approximate the necessary

a. Frequency deviation

b. Bandwidth

c. Capture ratio

d. Modulation index

8 An FM transmitter has an output power of 500 W when it isnot modulated. When intelligence is added, its modulationindex is 2.0. What is its output power with a modulation indexof 2.0?

a. 250 W

b. 500 W

c. 1000 Wd. 2000 W

9 Another way to describe the modulation index is using the

a. Deviation ratio

b. Deviation constant

c. Capture ratio

d. Maximum deviation

10 The inherent ability of FM to minimize the effect of undesiredsignals operating at the same or nearly the same frequencyas the desired station is known as the

a. Capture effect

b. Signal-to-noise ratio

c. Noise figure

d. Bessel function

11 In a Crosby FM transmitter, an FM signal having a centerfrequency of 2.04 Mhz and a deviation of 69 Hz is passedthrough four cascaded frequency multiplier stages: two

triplers, one doubler, and one quadrupler. What type of signalappears at the output of the last multiplier stage?

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

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  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

12 The circuitry used to increase the operating frequency of atransmitter up to a specified value is called the

a. Multiplierb. Expander

c. Pump chain

d. All the above

13 The purpose of the matrix network in a stereo FM broadcasttransmitter 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 carriersignal

14 An FM signal has an intelligence frequency of 5 kHz and amaximum deviation of 25 kHz. Its index of modulation is

a. 125

b. 0.2

c. 5

d. 6

15 Frequency multipliers

a. Are used to multiply the frequency of the carrier signal ofan FM signal

b. Consist of a class C amplifier followed by a tank circuit thatfilters out a single harmonic

c. Are used to multiply the frequency deviation of an FMsignal

d. All the above

Chapter 6: Frequency Modulation Reception

1 A difference between AM and FM receiver blockdiagrams is that the FM version includes a

a. Limiterb. Discriminatorc. Deemphasis networkd. All the above

2 An FM receiver rarely works satisfactorily without anRF amplifier because

a. FM receivers typically work with smaller input signallevels due to thei noisecharacteristics

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 todecode stereo signals.

3 A certain FM receiver provides a voltage gain of 113dB prior to its limiter. The limiter's quieting voltage is400 mV. Its sensitivity is approximately

a.b.

c.

d.

4 The use of dual-gate MOSFETs in RF amplifier stages

a. Offers increased dynamic range over those ofJFETsb. Produces higher-frequency responses than doJFETsc. Produces higher values of voltage gain than doJFETs

d. Is not compatible with AGC

5 The Foster-Seely detector design is superior to theratio detector in that it

a. Does not respond to any undesired amplitudevariationsb. Also provides an output AGC signalc. Offers superior linear response to wideband FMdeviationsd. Does not need a limiter stage

6 Local oscillator reradiation refers to radiation throughthe

a. Receiver's wiringb. IF transformerc. Antennad. All the above

7 Which is not one of the three stages in which a PLLcan be operated?

a. Free-runningb. Capturec. Locked/trackingd. Searching

8 A PLL is set up so that its VCO free-runs at 8.9 Mhz.The VCO does not change frequency unless its inputis within 75 kHz of 8.9 Mhz. After it does lock, theinput frequency can be adjusted within 120 kHz of8.9 Mhz without having the PLL start to free-run again.The capture range of the PLL is

a. 75 kHzb. 120 kHzc. 150 kHzd. 240 kHz

9 Slope detection is seldom used due to

a. Nonlinearity

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  b. Attenuationc. Complexityd. All the above

10 In an FM stereo receiver, what is the purpose of the23 –53-kHz filter?

a. To filter out the SCA signal at the output of thediscriminatorb. To filter out the L

 – R signal at the output of the

discriminatorc. To filter out the L + R signal at the output of thediscriminatord. To produce separate L and R signals from the L +R and L – signals

11 A dual audio amplifier is rated to provide 65 dB ofchannel separation. If the right channel has 4 W ofoutput power, how much of this power could be due tothe left channel intelligence?

a. 4 Wb. 79 nW

c. 1.26 Wd. 2.25 mW

12 The hold-in range for a PLL concerns the

a. Range of frequencies in which it will remain lockedb. Allowable range of dc voltagec. Allowable range of ac input voltaged. Satisfactory range of operating temperatures

13 The input signal into a PLL is at the

a. VCOb. Low-pass filterc. Comparatord. Phase detector

14 The square-law relationship of the FETs input versusoutput

a. Allows for greater sensitivity in an FM receiverb. Provides improved noise performancec. Reduces shot noised. Minimizes cross-modulation

15 When troubleshooting a stereo demodulator, the inputsignal should be abouto

a.

b.c. 1 mV rmsd. 100 mV rms

Chapter 7 Communication Technique

1 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 superheterodyne design.

2 The tuned circuits prior to the mixer in a superheterodynereceiver are called the

a. Front end

b. Tuner

c. Preselector

d. All the above

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

a. S meterb. Signal meter

c. Strength meter

d. All the above

4 An AM broadcast receiver has two identical tuned circuitswith a Q of 50 prior to the IF stage. The IF frequency is 460kHz and the receiver is tuned to a station on 550 kHz. Theimage-frequency rejection is

a. 41 dB

b. 36.2 dBc. 72.4 dB

d. 82 dB

5 An AGC that causes a step reduction in receiver gain at somearbitrarily high value of received signal in order to preventoverloading the receiver is known as

a. Arbitrary AGC

b. Auxiliary AGC

c. Delayed AGC

6 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

7 The range over which the input to a receiver or amplifierprovides a usable output is called the

a. Level of acceptability

b. Dynamic range

c. Degree of usefulness

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  d.Specified input

8 A receiver has a 30-dB noise figure, a 1.5 Mhz bandwidth, a6-dBm third intercept point, and a 3-dB signal-to-noise ratio.Its sensitivity is

a. –94 dB

b. –82.2 dB

c. –79.2 dB

d. –81 dB

9 Two-modulus dividers are used in the synthesis offrequencies 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 basicprogrammable divider designs

d. All the above

10 The disadvantage of direct digital synthesizers (DDS) overanalog frequency synthesizers is

a. Its complexity and cost

b. Its limited maximum output frequency

c. Its higher phase noise

d. All the above

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

a. An HF amateur transceiver using AM and SSB modulationmodes

b. A VHF commercial transceiver using the FM modulationmode and a channel guard function

c. A military transceiver using all modes on HF frequencies

d. A cellular telephone transceiver

12 The type of radio transmission that uses pseudorandomlyswitched frequency or time transmissions is known as

a. Synthesizingb. Facsimile

c. Spread spectrum

d. Compression

13 The acronym CDMA refers to ________.

a. Carrier-division multiple-access systems

b. Capture-division multiple-access systems

c. Code-division multiple-access systems

d. Channel-division multiple-access systems

14 A typical problem encountered when troubleshooting afrequency synthesizer is

a. A small frequency error

b. A large frequency error

c. No output

d. All the above

15 A transceiver is

a. A transmitter that can be tuned to several bands offrequencies

b. A transmitter that transmits digital data

c. A receiver that receives digital data

d. A transmitter and receiver in a single package

Chapter 8 Digital Communication : Coding Technique

1 The advantage(s) of digital and/or data communications overanalog include

a. Noise performance

b. Regeneration

c. Digital signal processing

d. All the above

2 In a S/H circuit, the time that it must hold the sampled voltageis

a. Aperture time

b. Acquisition time

c. Flat-top timed. Dmin

3 Error signals associated with the sampling process are called

a. Foldover distortion

b. Aliasing

c. Nyquist rate

d. a and b

4 Which of the following is not a common RZ code?

a. RZ-unipolar

b. RZ-bipolar

c. RZ-M

d. RZ-AMI

5 In an asynchronous data system

a. Both sender and receiver are exactly synchronized to thesame clock frequency.

b. Each computer word is preceded by a start bit and followed

by a stop bit to frame the word.c. The receiver derives its clock signal from the received datastream.

d. All the above.

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6 A CD audio laser-disk system has a frequency bandwidth of20 Hz to 20 kHz. The minimum sample rate to satisfy theNyquist criteria is

a. 20 Hz

b. 20 kHz

c. 40 Hz

d. 40 kHz

7 With respect to converter circuits

a. DACs include an ADC

b. ADCs include a DAC

c. DACs and ADCs are virtually identical

d. All the above.

8 The type of modulation that uses sampling on one of the

parameters of the transmitted and received signal is knownas

a. Phase modulation

b. Pulse modulation

c. Amplitude modulation

d. Frequency modulation

9 An alphanumeric code for representing the decimal valuesfrom 0 to 9 that is based on the relationship that only one bitin a binary word changes for each binary step is known as

a. ASCII

b. EBCDIC

c. Baudot code

d. Gray code

10 The quantizing error of PCM systems for weak signals can bemade less significant by

a. Companding

b. Using time-division multiplexing

c. Using frequency-division multiplexingd. Filtering out the alias frequency

11 When the message and the BCC are transmitted as separateparts within the same transmitted code, it is called a(n)

a. Systematic code

b. CRC

c. (n,k) cyclic code

d. Interleaved code

12 The value left in the CRC dividing circuit after all data havebeen shifted in is the

a. Quantile interval

b. Codec

c. BCC

d. Syndrome

13 Which of the following is not an example of code errordetection and correction in a data communication channel?

a. Parity

b. Frequency-shift keying

c. Block-check character

d. Hamming code

14 Error-correcting techniques that allow for correction at thereceiver are called

a. Cyclic redundancy checks (CRC)

b. Block-check characters (BCC)

c. Forward error correcting (FEC)

d. Parity

15 Codes producing random data that closely resemble digitalnoise are

a. Systematic codes

b. PN codes

c. Pseudonoise codes

d. b and c

Chapter 9 Digital Communications Transmission

1 Using an oscilloscope to display overlayed received data bitsthat provide information on noise, jitter, and linearity is calleda(n)

a. Constellation pattern

b. Loopback

c. Statistical Concentration

d. Eye pattern

2 Why isn't Morse code well suited to today's telegraphicequipment?

a. It uses an automatic request for repetition.

b. It has excessive redundancy built into the code.

c. The parity bit is difficult to detect.

d. Differing between various widths of the pulses is anextremely complicated process.

3 A special digital modulation technique that achieves high data

rates in limited-bandwidth channels is called

a. Delta modulation

b. Pulse-coded modulation (PCM)

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  c. Quadrature amplitude modulation (QAM)

d. Pulse amplitude modulation (PAM)

4 FSK systems are much superior to two-tone amplitude-modulation systems with respect to

a. Noise performance

b. Bandwidth requirements of the channelc. Ionospheric fading characteristics

d. Power consumption

5 Which is not a type of pulse modulation?

a. Pulse-amplitude modulation (PAM)

b. Pulse-width modulation (PWM)

c. Pulse-frequency modulation (PFM)

d. Pulse-position modulation (PPM)

6 PPM and PWM are superior to PAM systems in

a. Noise characteristics

b. Bandwidth characteristics

c. Simplicity in design

d. Frequency response of the intelligence signal

7 Half-duplex operation involves communication

a. In one direction only

b. In both directions, but only one can talk at a timec. Where both parties can talk at the same time

d. All the above

8 A procedure that decides which device has permission totransmit at a given time is called

a. Line control

b. Protocol

c. Flow control

d. Sequence control

9 The technique that uses the BPSK vector relationship togenerate an output with logical 0s and 1s determined bycomparing the phase of two successive data bits is

a. CSU/DSU

b. TDM

c. CVSD

d. DPSK

10 Using radio to transmit gathered data on some particular

phenomenon without the presence of human monitors isknown as

a. Radio teletype

b. Radio multiplexing

c. Radio facsimile

d. Radio telemetry

11 The bit error rate is

a. The number of bit errors that occur for a given number ofbits transmitted

b. The most common method of referring to the quality of adigital communication system

c. Virtually the same as the error probability

d. All the above

12 The major difficulty faced by delta modulators is

a. Excessive noise producing errors

b. Slope overload

c. Insufficient frequency response of the intelligence signal

d. Complexity of design

13 The capacity of a telephone channel that has an S/N of 2047if its bandwidth is 3.5 kHz is

a. 30,000 bits per second

b. 33,000 bits per second

c. 38,500 bits per second

d. 35,000 bits per second

14 The AT&T T1 lines

a. Use 16-bit PCM code and include 24 voice channels

b. Use delta modulation and include 48 voice channels

c. Use 8-bit PCM code and include 24 voice channels

d. Use delta modulation and include 24 voice channels

15 A digital transmission has an error probability of and

is long. Its expected number of error bits is

a.

b.c.

d.

Chapter 10 Network Communications

1 An interconnection of users that allows communication withone another is known as a

a. Modem

b. UARTc. Network

d. Protocol

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2 A complex LC filter that removes delay distortion from signalsthat are traveling down long transmission lines is called a(n)

a.. Delay equalizer

b. UART

c. Attenuation distortion filter

d. Trunk switcher

3 Which of the following is not a way that designers oftelephone equipment are adapting to the increasing use ofcomputers and digital coding in telephone communicationlinks?

a. The use of shorter transmission lines

b. The use of computers in finding unused portions ofmultiplex systems to maximize use

c. The application of digital switching theory to increasechannel capacity

d. Sharing of communication links by voice and data signals

4 The advanced mobile phone services (AMPS) is an exampleof

a. A cellular telephone system

b. A telephone system that uses frequency reuse

c. A cell -splitting telephone system

d. All the above

5 Which is not a major function of a protocol?

a. Framing

b. Line control

c. Flow control

d. Topology

e. Sequence control

6 The LAN that was developed by Xerox, Digital EquipmentCorporation, and Intel in 1980 is called

a. IEEE-488

b. Ethernetc. OSI

d. CSMA/CD

7 A device interconnecting two networks that use differentprotocols and formats is called a

a. Bridge

b. Gateway

c. Router

d. Node

8 A device interconnecting LANs together that usually haveidentical protocols at the physical and data link layers iscalled a

a. Bridge

b. Gateway

c. Router

d. Node

9 In telephony, traffic is defined in

a. Hundred-call seconds

b. Average number of calls in a specific period of time

c. Erlang

d. All the above

10 The Internet and the WWW are

a. The same thing

b. Completely different

c. Related

d. Local area networks

11 In a telephone system, the grade of service is

a. The ratio of calls lost to calls offered

b. The ratio of traffic lost to traffic offered

c. The ratio of calls offered to calls lost

d. The ratio of traffic offered to traffic lost

e. a and b

12 The following term is not a major concept in cellular phonesystems.

a. Frequency reuse

b. Cell reuse

c. Cell splitting

d. Handoff

13 In local area networks, the following topology or topologiesare seldom used.

a. Starb. Ring

c. Bus

d.a and b

14 The following numeric describing data rates for copper coaxand twisted pair is rarely used

a. 10 Base 2

b. 10 Base 5

c. 10 Base T

d. 100 Base FX

e. a and b

15 The xDSL service with the highest projected data rate is

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a. VDSL

b. SDSL

c. HDSL

d. IDSL

e. ADSL

Chapter 11 Transmission Lines

1 The chief advantage of coaxial cable over open-wire line is

a. Minimized radiation losses

b. Low cost

c. Low noise pick up

d. Low resistive losses

2 Unshielded twisted-pair cable is

a. Seldom used due to noise problems

b. Increasingly used in computer networking

c. More costly than coaxial cable

d. All the above

3 The ratio of actual velocity to free-space velocity is called

a. Velocity factor

b. Relative dielectric constant

c. Velocity of propagation

d. Delay time

4 In a balanced line, the same current flows in each line but is

a. 45º out of phase

b. 90º out of phase

c. 180º out of phase

d. 270º out of phase

5 What is the length of a quarter-wavelength section of RG-

8A/U coaxial cable at a frequency of 144.2 Mhz if its velocityfactor is 0.69.

a. 52.1 cm

b. 35.9 cm

c. 143.6 cm

d. 2.08 m

6 A nonlossy transmission line that is terminated with aresistive load that is equal to the characteristic impedance ofthe line

a. Has the same impedance at all points along the line

b. Has a VSWR of 1:1

c. Has the same voltage at points along the line

d. Has a reflection coefficient at the load equal to zero

e. All the above

7 A flat line indicates

a. No reflection

b. VSWR = 1

c. No physical imperfectionsd. a and b

8 A nonlossy transmission line terminated with a short circuithas an

a. In-phase reflected voltage that is equal in magnitude to theincident voltage

b. Opposite-phase reflected voltage that is equal inmagnitude to the incident voltage

c. In-phase reflected voltage that is smaller in magnitude than

the incident voltaged. Opposite-phase reflected voltage that is smaller inmagnitude than the incident voltage

9 A manufacturer's specification dealing with crosstalk andattenuation is

a. ACR

b. CAS

c. CAA

d. AAC

10 A 50- transmission line that has a load impedance of 300

has a VSWR of

a. 6:1

b. 1:6

c. 0.666:1

d. 1.5:1

11 The input impedance of a quarter-wavelength section of a 50-

 transmission line that is terminated with a short is

a. 50

b. 0 (a short)

c. Infinite (open)

d. 100

12 A device that is used to match an unbalanced transmissionline to a balanced transmission line is called a

a. Quarter-wavelength matching transformer

b. Balun

c. Shorted-stub section

d. Slotted line

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13 A 50- transmission line with a 300- load impedancehas a reflection coefficient of

a. 6

b. 0.166

c. 0.714

d. 1.4

14 A cable has an inductance of 1 nH/ft and capacitance of 1nF/ft. The delay introduced by a 1-ft section is

a. Not able to be calculated with the given information

b.

c.

d.

15 A transmission line can be used as a(n)

a. Inductor

b. Capacitor

c. Filter

d. Matching section

e. All the above

Chapter 12 Wave Propagation

1 An antenna can be thought of as a(n)

a. Oscillator

b. Capacitor

c. Transducer

d. Frequency multiplexer

2 A wave that is characterized by having its direction ofpropagation perpendicular to its oscillation is known as

a. Isotropic

b. Transverse

c. Polarizedd. Refractive

3 Which is not an effect of our environment on wavepropagation?

a. Radiation

b. Reflection

c. Refraction

d. Diffraction

4 A point in space that radiates electromagnetic energy equallyin all directions is called

a. Transverse

b. Isotropic point source

c. Omnisphere

d. Shadow zone

5 The process of waves, which traveling in straight paths,bending around an obstacle is

a. Radiationb. Reflection

c. Refraction

d. Diffraction

6 Which is not one of the basic modes of getting a radio wavefrom the transmitting to receiving antenna?

a. Ground wave

b. Shadow wave

c. Space wave

d. Satellite link

e. Sky wave

7 The type of wave that is most affected by the D, E, and Flayers of the ionosphere is:

a. Ground wave

b. Space wave

c. Sky wave

d. Satellite

8 The largest frequency that will be returned to earth whentransmitted vertically under given ionospheric conditions iscalled the

a. Critical frequency

b. Maximum usable frequency (MUF)

c. Optimum working frequency (OWF)

d. Skip zone

9 The characteristic impedance of free space is

a. Not known

b. Infinite

c. 50

d. 377

10 The area between the point where the ground wave ends andfirst sky wave returns is called the

a. Quiet zone

b. Skip zone

c. Null Zoned. All the above

e. a and b

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11 The refraction and reflection action of a skywave between theionosphere and ground is known as

a. Space diversity

b. Skip

c. Tropospheric scattering

d. Fading

12 A satellite communication system used by companies suchas K-Mart to quickly verify credit cards and check inventorydata is called

a. VSAT

b. MSAT

c. SATCOM

d. WESTAR

13 A common type of radio wave interference is

a. EMI

b. Fading

c. Reflections

d. All the above

14 Diversity reception does not include:

a. Space diversity

b. Time diversity

c. Frequency diversity

d. Angle diversity

15 When installing a receiving antenna, you can often overcomediffraction problems by finding a

a. Null zone

b. Downlink

c. Hot spot

d. Skip zone

Chapter 13 Antennas

1 The process of interchangeability of receiving andtransmitting operations of antennas is known as

a. Polarization

b. Reciprocity

c. Efficiency

d. Counterpoise

2 A half-wave dipole antenna is also known as

a. Marconi antenna

b. Hertz antenna

c. Vertical antenna

d. Phased array

3 An antenna that is a quarter-wavelength long connected suchthat the ground acts as a reflecting quarter-wavelengthsection is called a

a. Hertz antenna

b. Dipole antenna

c. Marconi antenna

d. All the above

4 The angular separation between the half-power points on anantenna's radiation pattern is the

a. Bandwidth

b. Front-to-back ratio

c. Lobe distribution

d. Beamwidth

5 The input impedance at the center of a dipole antenna isapproximately

a. 36.6

b. 50

c. 73

d. 300

6 As the height of a half-wavelength antenna is reduced belowa quarter-wavelength, the radiation resistance

a. Increases

b. Decreases

c. Remains the same

d. All the above

7  A dipole antenna is being fed with a 300 transmission line.If a quarter-wave matching transformer is to be used as thenon-resonant matching section, what must be thecharacteristic impedance of the cable used in the matchingtransformer?

a. 186.5

b. 103.9

c. 122.5

d. 147.9

8 An impedance-matching device that spreads the transmissionline as it approaches the antenna is called a

a. Delta match

b. Quarter-wave matching device

c. Director

d. Counterpoise

9 A loading coil is often used with a Marconi antenna in order to

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a. Tune out the capacitive reactance portion of the inputimpedance of the antenna

b. Tune out the inductive reactance portion of the inputimpedance of the antenna

c. Raise the input impedance of the antenna

d. Decrease the losses of the antenna

10 Standard AM broadcast stations usually use what type oftransmitting antennas?

a. Driven collinear array

b. Marconi array

c. Yagi-Uda

d. Log-periodic

11 The type of antenna often found in small AM broadcastreceivers is a

a. Ferrite loop antenna

b. Folded dipole antenna

c. Slot antenna

d. Log-periodic antenna

12 The folded dipole antenna has

a. Greater bandwidth than a half-wave dipole

b. A 288- input impedance

c. Less bandwidth than a half-wave dipole

d.. a and b

e. b and c

13 The Yagi-Uda antenna consists of

a. A driven director and parasitic reflector

b. A driven reflector and parasitic director

c. A parasitic director and reflector

d. All the above

14 A grid-dip meter measures the resonant frequency of tunedcircuits

a. By connection in series with the inductance

b. By connection in parallel with the inductance

c. Without power being applied to the tuned circuit

d. By connection in series with the capacitance

15 When troubleshooting antennas, the level of VSWR thatindicates a problem is

a. Greater than 1b. Less than 1

c. Greater than 1.5

d. Less than 0.5

Chapter 14 Waveguides & RADAR

1 At a frequency of 1 Ghz and transmitter-receiver distance of30 mi, which is the most efficient device for energy transfer?

a. Transmission lines

b. Waveguides

c. Antennas

d. None of the above

2 The most efficient means of transmitting a 1-Ghz signal 1500ft would typically be

a. Transmission lines

b. Waveguides

c. Antennasd. None of the above

3 The dominant mode for waveguide operation is

a. TE10

b. TE01

c. TM10

d. TM01

4 The propagation velocity of the signal in a waveguide, whencompared to the speed of light is

a. larger

b. smaller

c. the same velocity

d. either b or c

5 Ridged waveguides are advantageous over rectangularwaveguides in their

a. cost

b. attenuation

c. ability to work at lower frequency

d. ease of construction

6 A circular waveguide is used for

a. Efficiency reasons

b. Ease of manufacture

c. Rotating section applications

d. Greater bandwidth

7 Variable attenuators are used in waveguides to

a. Isolate a source from reflections at its load so as to

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preclude frequency pulling.

b. Adjust the signal levels.

c. Measure signal levels.

d. All the above.

8 The coupling in dB of a directional coupler that has 85 mWinto the main guide and 0.45 mW out the secondary guide is

a. 22.8

b. 18.9

c. 188.9

d. 45.6

9 The resonant frequency of a cavity may be varied bychanging the cavity's

a. Volume

b. Inductance

c. Capacitance

d. All the above

10 The guide wavelength is

a. Greater than free-space wavelength

b. Equal to free-space wavelength

c. Less than free-space wavelength

d. All the above

11 The process of employing radio waves to detect and locatephysical objects is known as

a. The Doppler effect

b. Radar

c. Directional coupling

d. Cavity tuning

12 The use of two grounded conductors that sandwich a smallerconductive strip with constant separation by a dielectricmaterial on a printed circuit board for use at frequenciesabove 500 Mhz is known as

a. Artwork traces

b. Dielectric waveguide

c. Microstrip/stripline

d. MICs or MMICs

13 Second return echoes are

a. Echoes produced when the reflected beam makes asecond trip

b. Echoes that arrive after the transmission of the next pulse

c. Echoes caused by the PRT being too long

d. All the above

14 The characteristic wave impedance for waveguides is

a. 75

b. 377

c. Dependent on frequency

d. Dependent on waveguide shape

e. c and d

15 A dielectric waveguide is

a. Enclosed by a conducting material

b. A waveguide with just a dielectric

c. Dependent on the principle that two dissimilar dielectricscan guide waves

d. b and c

Chapter 15 Microwaves & Lasers

1 Which is not a type of horn antenna design for microwavefrequencies?

a. Parabolic horn

b. Circular horn

c. Pyramidal horn

d. Sectoral horn

2 Cassegrain feed to a paraboloid antenna involves a

a. Dipole antennab. Point-source antenna

c. Secondary reflector

d. Any of the above

3 Calculate the beamwidth of a microwave dish antenna with a6-m mouth diameter when used at 5 Ghz.

a. 0.49°

b. 4.9°

c. 7°

d. 0.7°

4 Zoning refers to

a. A method of producing a radome

b. Changing a spherical wavefront into a plane wave

c. Creating a polar radiation pattern

d. Fading into nonreality

5 Which microwave oscillator has high gain, low-noisecharacteristics, and wide bandwidth?

a. Traveling wave tube oscillator

b. Gunn Oscillator

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  c.Klystron oscillator

d. Magnetron oscillator

6 Which is not an advantage of the Gunn gallium arsenideoscillator?

a. Ease of removing heat from the chip

b. Small sizec. Ruggedness

d. Lack of filaments

e. Low cost of manufacture

7 The i in P-I-N diode refers to

a. Indium

b. Impact

c. Integrated

d. Intrinsic

8 Which is not a typical application of a ferrite in a microwavesystem?

a. attenuator

b. amplifier

c. isolator

d. circulator

9 A low noise microwave amplifier that provides amplificationvia the variation of a reactance is known as a

a. Maser

b. Laser

c. Yig

d. Parametric amplifier

10 The major difference between a laser and a maser is the

a. Frequency of the signal being amplified

b. Amplitude of the signal being amplified

c. Bandwidth of the signal being amplifiedd. Phase of the signal being amplified

11 Lasers are useful in

a. Industrial welding

b. Surgical procedures

c. Distance measuring

d. Compact disc players

e. All the above

12 The following semiconductor is not used as a microwavedevice:

a. PIN diode

b. Baritt diode

c. Zener diode

d. Tunnel diode

13 Which of the following represent typical failure mode(s) for aTWT amplifier?

a. Low gainb. Spurious modulation

c. Poor frequency response

d. Low RF output

e. All the above

14 Which of the following is not used as a microwave antenna?

a. Patch antenna

b. Marconi antenna

c. Lens antenna

d. Horn antenna

15 Compared to linear power supplies, switching power suppliesare

a. Less efficient

b. More efficient

c. Simpler

d. Heavier

Chapter 16 Television

1 A television transmitter actually transmits two signals at once.They are

a. An amplitude-modulated video signal and frequency-modulated audio signal

b. Two amplitude-modulated signals: video and audio

c. An amplitude-modulated audio signal and frequency-modulated video signal

d. Two frequency-modulated signals: video and audio

2 The most widely used type of TV camera is the

a. Charge couple device

b. Vidicon

c. Image orthicon

d. Iconoscope

3 Synchronizing pulses that consist of equalizing pulses,followed by serrations, followed by more equalizing pulses ata rate of 60 times per second are called

a. Color synchronizing pulses

b. Horizontal retrace pulses

c. Vertical retrace pulses

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  d. Eight-cycle back-porch pulses

4 The frame frequency for U.S. television broadcasts isapproximately

a. 30 frames per second

b. 40 frames per second

c. 60 frames per secondd. 100 frames per second

5 Channel 12 on U.S. television extends from 204 to 210 Mhz.The channel 12 carrier frequency is Approximately

a. 204.5 Mhz

b. 205.25 Mhz

c. 211.25 Mhz

d. 211.75 Mhz

6 The length of time an image stays on the screen after thesignal is removed is termed

a. Retention

b. Flicker

c. Persistence

d. Back porch

7 Which is not part of the tuner section of a TV receiver?

a. The rf amplifier stageb. The mixer stage

c. The local oscillator stage

d. The video-detector stage

8 The stage in a TV receiver that filters out the vertical andhorizontal retrace pulses from the video signal is the

a. Video detector

b. Video IF amplifier

c. Sync separator

d. Sound detector

9 The winding around the CRT yoke that deflects the electronbeam with its magnetic field is called the

a. Coil

b. Yoke

c. Deflector

d. Magneto

10 A cumbersome series of adjustments to a color TV receiver inorder to make sure that the three electron beams of thepicture tube are positioned exactly on their respective colordots on the face of the picture tube is called

a. Alignment

b. Convergence

c. Interleaving

d. Interlacing

11 A faulty TV receiver having symptoms of normal sound and

raster but no picture must have a problem in the

a. Horizontal or vertical oscillator or high-voltage powersupply

b. Main power supply

c. Video amplifiers following the sound takeoff

d. RF, IF, or video amplifiers prior to the sound takeoff

12 Raster refers to

a. CRT illumination by scan lines when no signal is being

receivedb. CRT resolution

c. CRT aspect ratio

d. All the above

13 The high voltage for the anode of the CRT is obtained fromthe low-voltage power supply using

a. Its power-line transformer

b. The yoke coil

c. The vertical oscillator

d. The flyback transformer

14 The introduction of digital television in the United States hasbeen hampered by

a. Delays in chip designs

b. Shortages of appropriate chips

c. Customer rejection

d. Less than ideal regulatory climate

15 When a digital picture freezes even when there is motion in

the video, it is

a. due to bandwidth problems

b. Called a pixelate

c. Due to noise

d. b and c

Chapter 17 Fiber Optics

1 Which is an advantage of optical communication links over

using transmission lines or waveguides?

a. Small size

b. Extremely wide bandwidths

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  c. Immunity to electromagnetic interference (EMI)

d. Lower cost

e. All the above

2 The most common light used in fiber-optic links is

a. Infra-red

b. Redc. Violet

d. Ultraviolet

3 The optical band designation(s) include

a. S

b. C

c. L

d. a and b above

e. All the above

4 In the telecommunications industry, the most commonly usedfiber(s) are

a. 50 micron

b. 62.5 micron

c. 50 and 62.5 micron

d. 125 micron

5 The abrupt change in refractive index from core to cladding of

fiber-optic cable is called the

a. Total internal reflection

b. Numerical aperture

c. Dispersion

d. Step index

6 A technique that is used to minimize the pulse dispersioneffect is to

a. Use a higher frequency light source

b. Use plastic cladding

c. Minimize the core diameter

d. All the above

7 The loss (attenuation) of signal in optical fiber is due to

a. Scattering

b. Absorption

c. Macrobending

d. Microbending

e. All the above

8 Calculate the optical power 100 km from a 0.5 mW source ona single mode fiber that has 0.10 dB per km loss.

a. 50 nW

b. 500 nW

c. 5 uW

d. 50 uW

9 Which is not an important characteristic of a light detector?

a. Responsitivity

b. Dark current

c. Power consumption

d. Response speed

e. Spectral respons

10 The dispersion in fiber optics is termed

a. Modal

b. Chromatic

c. Polarization mode

d. All the above

e. a and b above

11 Fiber optic connections suffer high loss due to

a. Air gaps

b. Rough surfaces

c. Axial misalignment

d. Angular misalignmente. All the above

12 Fiber optic technology is used in applications of

a. Local area networks (LANs)

b. Cable TV (CATV) systems

c. Telephone networks

d. All the above

13 The dispersion of light in fiber-optic cable caused by a portion

of the light energy traveling in the cladding is called

a. Modal dispersion

b. Material dispersion

c. Waveguide dispersion

d. Cable dispersion

14 Recent laser developments for fiber optic communicationinclude

a. Distributed feedback (DFB)

b. Heterojunction

c. Vertical cavity surface emitting (VCSEL)

d. a and b above

e. a and c above

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15 The following consideration is important when decidingbetween using a diode laser or an LED

a. Response time

b. Power levels

c. Temperature sensitivity

d. Failure characteristicse. All the above

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 ANSWER KEY

CHAPTER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

1 C D C C E D B D D C A C B C A A E

2 B A C D B A C A D A B B B B C A A

3 D C C D B C A D C A A A C A D C E

4 C B B A B A D C C D C B D B B A C

5 D C D B C C B B C D B D C C A B D

6 C D C D B C D D A B E B B C A C C

7 C C A B B D B B B B D C D D D D E

8 B D C A B C C B A A B A A A B C D

9 D A D D A A D D D D A D A D D B C

10 A C A B A B D A D C A E B A A B D

11 A A C C B C B A D E C B A B E C E

12 B D D B C A C D B B B A D C C A D

13 C D D A B D C B C C C D C B E D C

14 C D D D C D D C C E B B C E B D E

15 E B A C D D D D A A E C C D B D A