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KENNEDY
CHAPTER 1: INTRODUCTION TO COMMUNICATION SYSTEM
1. In a communication system, noise is most likely to affect the signal
a. at the transmitterb. in the channelc. in the information sourced. at the destination
1. In a communication system, noise is most likely to affect the signal
a. at the transmitterb. in the channelc. in the information sourced. at the destination
2. Indicate the false statement. Fourier analysis shows that the saw tooth wave consist of
a. fundamental and sub harmonic sine waves
b. a fundamental sine wave and an infinite number of harmonics
c. fundamental and harmonic sine waves whose amplitude decreases with the harmonic number
d. sinusoidal voltages, some of which are small enough to ignore in practice
2. Indicate the false statement. Fourier analysis shows that the saw tooth wave consist of
a. fundamental and sub harmonic sine waves
b. a fundamental sine wave and an infinite number of harmonics
c. fundamental and harmonic sine waves whose amplitude decreases with the harmonic number
d. sinusoidal voltages, some of which are small enough to ignore in practice
3. Indicate the false statement. Modulation is used to
a. reduce the bandwidth usedb. separate the differing
transmissionsc. ensure that intelligence may be
transmitted over long distancesd. allow the use of practicable
antennas
3. Indicate the false statement. Modulation is used to
a. reduce the bandwidth usedb. separate the differing
transmissionsc. ensure that intelligence may be
transmitted over long distancesd. allow the use of practicable
antennas
4. Indicate the false statement. From the transmitter the signal deterioration because of noise is usually
a. unwanted energyb. predictable in characterc. present in the transmitterd. due to any cause
4. Indicate the false statement. From the transmitter the signal deterioration because of noise is usually
a. unwanted energyb. predictable in characterc. present in the transmitterd. due to any cause
5. Indicate the true statement. Most receivers conforms to the
a. amplitude-modulated groupb. frequency-modulated groupc. superheterodyne groupd. tuned radio frequency receiver
group
5. Indicate the true statement. Most receivers conforms to the
a. amplitude-modulated groupb. frequency-modulated groupc. superheterodyne groupd. tuned radio frequency receiver
group
6. Indicate the false statement. The need for modulation can best be exemplified by the following.
a. antenna lengths will be approximately /4 long
b. an antenna in the standard broadcast AM band is 16,000 ft
c. all sound is concentrated from 20 Hz to 20 kHz
d. a message is composed of unpredictable variations in both amplitude and frequency
6. Indicate the false statement. The need for modulation can best be exemplified by the following.
a. antenna lengths will be approximately /4 long
b. an antenna in the standard broadcast AM band is 16,000 ft
c. all sound is concentrated from 20 Hz to 20 kHz
d. a message is composed of unpredictable variations in both amplitude and frequency
7. Indicate the true statement. The process of sending and receiving started as early as
a. the middle 1930sb. 1850c. the beginning of the twentieth
centuryd. the 1840s
7. Indicate the true statement. The process of sending and receiving started as early as
a. the middle 1930sb. 1850c. the beginning of the twentieth
centuryd. the 1840s
8. Which of the steps is not included in the process of reception?
a. decodingb. encodingc. storaged. interpretation
8. Which of the steps is not included in the process of reception?
a. decodingb. encodingc. storaged. interpretation
9. The acoustic channel is used for which of the following?
a. UHF communicationsb. single-sideband communicationc. television communicationsd. person-to-person voice
communications.
9. The acoustic channel is used for which of the following?
a. UHF communicationsb. single-sideband communicationc. television communicationsd. person-to-person voice
communications.
10. Amplitude modulation is the process of
a. superimposing a low frequency on a high frequency
b. superimposing a high frequency on a low frequency
c. carrier interruptiond. frequency shift and phase shift
10. Amplitude modulation is the process of
a. superimposing a low frequency on a high frequency
b. superimposing a high frequency on a low frequency
c. carrier interruptiond. frequency shift and phase shift
CHAPTER 2: NOISE
1. One of the following types of noise becomes a great importance at high frequencies. Is the
a. shot noiseb. random noisec. impulse noised. transit-time noise
1. One of the following types of noise becomes a great importance at high frequencies. Is the
a. shot noiseb. random noisec. impulse noised. transit-time noise
2. Indicate the false statementa. HF mixers are generally noisier
than HF amplifiersb. Impulse noised voltage is
independent of the bandwidthc. Thermal noise is independent of the
frequency at which it is measuredd. Industrial noise is usually of the
impulse type
2. Indicate the false statementa. HF mixers are generally noisier
than HF amplifiersb. Impulse noised voltage is
independent of the bandwidthc. Thermal noise is independent of the
frequency at which it is measuredd. Industrial noise is usually of the
impulse type
3. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore
a. halvedb. quadrupledc. doubled. unchanged
3. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore
a. halvedb. quadrupledc. doubled. unchanged
4. One of the following is not useful quantity for comparing the noise performance of the receiver
a. Input noise voltageb. Equivalent noise resistancec. Noise temperatured. Noise figure
4. One of the following is not useful quantity for comparing the noise performance of the receiver
a. Input noise voltageb. Equivalent noise resistancec. Noise temperatured. Noise figure
5. Indicate the noise whose source is in a category different from that of the other three.
a. solar noiseb. cosmic noisec. atmospheric noised. galactic noise
5. Indicate the noise whose source is in a category different from that of the other three.
a. solar noiseb. cosmic noisec. atmospheric noised. galactic noise
6. Indicate the false statement. The square of the thermal noise voltage generated by a resistor is proportional to
a. its resistanceb. its temperaturec. Boltzmann’s Constantd. the bandwidth over which it is
measured
6. Indicate the false statement. The square of the thermal noise voltage generated by a resistor is proportional to
a. its resistanceb. its temperaturec. Boltzmann’s Constantd. the bandwidth over which it is
measured
7. Which of the broad classifications of noise are most difficult to treat?
a. noise generated in the receiverb. noise generated in the
transmitterc. externally generated noised. internally generated noise
7. Which of the broad classifications of noise are most difficult to treat?
a. noise generated in the receiverb. noise generated in the
transmitterc. externally generated noised. internally generated noise
8. Space noise generally covers a wide frequency spectrum, but the strongest interference occurs
a. between 8MHz and 1.43 GHzb. below 20 MHzc. between 20 to 120 MHzd. above 1.5 GHz
8. Space noise generally covers a wide frequency spectrum, but the strongest interference occurs
a. between 8MHz and 1.43 GHzb. below 20 MHzc. between 20 to 120 MHzd. above 1.5 GHz
9. When dealing with random noise calculations it must be remembered that
a. all calculations are based on peak to peak values
b. calculations are based on peak values
c. calculations are based on average values
d. calculations are based on RMS values
9. When dealing with random noise calculations it must be remembered that
a. all calculations are based on peak to peak values
b. calculations are based on peak values
c. calculations are based on average values
d. calculations are based on RMS values
10. Which of the following is the most reliable measurement for comparing amplifier noise characteristics?
a. signal-to-noise ratiob. noise factorc. shot noised. thermal noise agitation
10. Which of the following is the most reliable measurement for comparing amplifier noise characteristics?
a. signal-to-noise ratiob. noise factorc. shot noised. thermal noise agitation
11. Which of the following statements is true?
a. Random noise power is inversely proportional to bandwidth
b. Flicker is sometimes called demodulation noise
c. Noise in mixers is caused by inadequate image frequency rejection
d. A random voltage across a resistance cannot be calculated
11. Which of the following statements is true?
a. Random noise power is inversely proportional to bandwidth
b. Flicker is sometimes called demodulation noise
c. Noise in mixers is caused by inadequate image frequency rejection
d. A random voltage across a resistance cannot be calculated
CHAPTER 3: AMPLITUDE MODULATION
1. If the plate supply voltage for a plate modulated class C amplifier is V, the maximum plate-cathode voltage could be almost as high as
a. 4Vb. 3Vc. 2Vd. V
1. If the plate supply voltage for a plate modulated class C amplifier is V, the maximum plate-cathode voltage could be almost as high as
a. 4Vb. 3Vc. 2Vd. V
2. In a low-level AM system, amplifiers following the modulated stage must be
a. linear devicesb. harmonic devicesc. class C amplifiersd. non linear devices
2. In a low-level AM system, amplifiers following the modulated stage must be
a. linear devicesb. harmonic devicesc. class C amplifiersd. non linear devices
3. If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be
a. 50b. 150c. 100d. 66.66
3. If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will be
a. 50b. 150c. 100d. 66.66
4. Leak type bias is used in a plate modulated class C amplifier to
a. prevent tuned circuit dampingb. prevent excessive grid currentc. prevent over modulationd. increase the bandwidth
4. Leak type bias is used in a plate modulated class C amplifier to
a. prevent tuned circuit dampingb. prevent excessive grid currentc. prevent over modulationd. increase the bandwidth
5. The output stage of a television transmitter is most likely to be a
a. plate modulated class C amplifierb. grid modulated class C amplifierc. screen modulated class C
amplifierd. grid modulated class A amplifier
5. The output stage of a television transmitter is most likely to be a
a. plate modulated class C amplifierb. grid modulated class C amplifierc. screen modulated class C
amplifierd. grid modulated class A amplifier
6. The modulation index of an AM is changed from 0 to 1. The transmitted power is
a. unchangedb. halvedc. doubledd. increase by 50percent
6. The modulation index of an AM is changed from 0 to 1. The transmitted power is
a. unchangedb. halvedc. doubledd. increase by 50percent
7. One of the advantages of base modulation over collector modulation of a transistor class C amplifier
a. the lower the modulating power required
b. high power output per transistorc. better efficiencyd. better linearity
7. One of the advantages of base modulation over collector modulation of a transistor class C amplifier
a. the lower the modulating power required
b. high power output per transistorc. better efficiencyd. better linearity
8. The carrier is simultaneously modulated by two sine wave with the modulation indices of 0.3 and 0.4; the total modulation index
a. is 1b. cannot be calculated unless the
phase relations are knownc. is 0.5d. is 0.7
8. The carrier is simultaneously modulated by two sine wave with the modulation indices of 0.3 and 0.4; the total modulation index
a. is 1b. cannot be calculated unless the
phase relations are knownc. is 0.5d. is 0.7
9. Amplitude modulation is used for broadcasting because
a. it is more noise immune than other modulation system
b. compared with other system it requires less transmitting power
c. its use avoids receiver complexity
d. no other modulation system can provide the necessary bandwidth for high fidelity
9. Amplitude modulation is used for broadcasting because
a. it is more noise immune than other modulation system
b. compared with other system it requires less transmitting power
c. its use avoids receiver complexity
d. no other modulation system can provide the necessary bandwidth for high fidelity
10. What is the ratio of the modulating power to the total power at 100 percent modulation?
a. 1:3b. 1:2c. 2:3d. None of the above
10. What is the ratio of the modulating power to the total power at 100 percent modulation?
a. 1:3b. 1:2c. 2:3d. None of the above
CHAPTER 4: SINGLE SIDE BAND TECHNIQUES
1. Indicate the false statement regarding the advantages of SSB over double sideband, full carrier AM.
a. More channel spaced availableb. Transmitter circuits must be
more stable. Giving better reception.
c. The signal is more noise-resistant.
d. Much less power is required for the same signal strength
1. Indicate the false statement regarding the advantages of SSB over double sideband, full carrier AM.
a. More channel spaced availableb. Transmitter circuits must be
more stable. Giving better reception.
c. The signal is more noise-resistant.
d. Much less power is required for the same signal strength
2. When the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is
a. Single sideband, full carrier (H3E)b. Vestigial sideband (C3F)c. Single-sideband, suppressed
carrier (J3E)d. Double sideband, full carrier
(A3E)
2. When the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is
a. Single sideband, full carrier (H3E)b. Vestigial sideband (C3F)c. Single-sideband, suppressed
carrier (J3E)d. Double sideband, full carrier
(A3E)
3. Indicate which one of the following advantages of the phase cancellation method of obtaining SSB over the filter method is false:
a. Switching from one sideband to the other is simpler
b. It is possible to generate SSB at any frequency
c. SSB with lower audio frequencies present can be generated
d. There are more balance modulator, therefore the carrier is suppressed better
3. Indicate which one of the following advantages of the phase cancellation method of obtaining SSB over the filter method is false:
a. Switching from one sideband to the other is simpler
b. It is possible to generate SSB at any frequency
c. SSB with lower audio frequencies present can be generated
d. There are more balance modulator, therefore the carrier is suppressed better
4. The most common used filters in SSB generation are
a. mechanicalb. RCc. LCd. low-pass
4. The most common used filters in SSB generation are
a. mechanicalb. RCc. LCd. low-pass
5. In an SSB transmitter, one is most likely to find a
a. class C audio amplifierb. tuned modulatorc. class B RF amplifierd. class A RF output amplifier
5. In an SSB transmitter, one is most likely to find a
a. class C audio amplifierb. tuned modulatorc. class B RF amplifierd. class A RF output amplifier
6. Indicate in which of the following only one sideband is transmitted:
a. H3Eb. A3Ec. B8Ed. C3F
6. Indicate in which of the following only one sideband is transmitted:
a. H3Eb. A3Ec. B8Ed. C3F
7. One of the following cannot be used to remove unwanted sideband in SSB. This is the
a. Filter systemb. Phase shift methodc. Third methodd. Balance modulator
7. One of the following cannot be used to remove unwanted sideband in SSB. This is the
a. Filter systemb. Phase shift methodc. Third methodd. Balance modulator
8. R3E modulation is sometimes used to
a. allow the receiver to have frequency synthesizer
b. simplify the frequency stability problem reception
c. reduce the power that must be transmitted
d. reduce the bandwidth required for transmission
8. R3E modulation is sometimes used to
a. allow the receiver to have frequency synthesizer
b. simplify the frequency stability problem reception
c. reduce the power that must be transmitted
d. reduce the bandwidth required for transmission
9. To provide two or more voice circuits with the same carrier, it is necessary to use
a. ISBb. Carrier reinsertionc. SSB with pilot carrierd. Lincompex
9. To provide two or more voice circuits with the same carrier, it is necessary to use
a. ISBb. Carrier reinsertionc. SSB with pilot carrierd. Lincompex
10. Vestigial sideband modulation (C3F) is normally used for
a. HF point to point communications
b. Monoaural broadcastingc. TV broadcastingd. Stereo broadcasting
10. Vestigial sideband modulation (C3F) is normally used for
a. HF point to point communications
b. Monoaural broadcastingc. TV broadcastingd. Stereo broadcasting
CHAPTER 5: FREQUENCY MODULATION
1. In the stabilized reactance modulator AFC system,
a. the discriminator must have a fast time constant to prevent demodulation
b. the higher the discriminator frequency, the better the oscillator frequency stability
c. the discriminator frequency must not be too low, or the system will fail
d. phase modulation is converted into FM by the equalizer circuit
1. In the stabilized reactance modulator AFC system,
a. the discriminator must have a fast time constant to prevent demodulation
b. the higher the discriminator frequency, the better the oscillator frequency stability
c. the discriminator frequency must not be too low, or the system will fail
d. phase modulation is converted into FM by the equalizer circuit
2. In the spectrum of a frequency modulated wave
a. the carrier frequency disappears when the modulation index is large
b. the amplitude of any sideband depends on the modulation index
c. the total number of sidebands depend on the modulation index
d. the carrier frequency cannot disappear
2. In the spectrum of a frequency modulated wave
a. the carrier frequency disappears when the modulation index is large
b. the amplitude of any sideband depends on the modulation index
c. the total number of sidebands depend on the modulation index
d. the carrier frequency cannot disappear
3. The difference between the phase and frequency modulation
a. is purely theoretical because they are the same in practice
b. is too great to make the two system compatible
c. lies in the poorer audio response of the phase modulation
d. lies in the different definitions of the modulation index
3. The difference between the phase and frequency modulation
a. is purely theoretical because they are the same in practice
b. is too great to make the two system compatible
c. lies in the poorer audio response of the phase modulation
d. lies in the different definitions of the modulation index
4. Indicate the false statement regarding the Armstrong modulation system,
a. the system is basically phase and not frequency modulation.
b. AFC is not needed, as the crystal oscillator is used.
c. Frequency multiplications must be used
d. Equalization is unnecessary.
4. Indicate the false statement regarding the Armstrong modulation system,
a. the system is basically phase and not frequency modulation.
b. AFC is not needed, as the crystal oscillator is used.
c. Frequency multiplications must be used
d. Equalization is unnecessary.
5. An FM signal with a modulation index mf is passed through the frequency tripler. The wave in the output of the Tripler will have a modulation index of
a. mf/3b. mfc. 3mfd. 9mf
5. An FM signal with a modulation index mf is passed through the frequency tripler. The wave in the output of the Tripler will have a modulation index of
a. mf/3b. mfc. 3mfd. 9mf
6. An FM signal with a deviation (δ) is passed through a mixer, and has its frequency reduced fivefold. The deviation in the output of the mixer is
a. 5 δb. Indeterminatec. δ / 5d. δ
6. An FM signal with a deviation (δ) is passed through a mixer, and has its frequency reduced fivefold. The deviation in the output of the mixer is
a. 5 δb. Indeterminatec. δ / 5d. δ
7. A pre-emphasis circuit provides extra noise immunity by
a. boosting the bass frequencyb. amplifying the high audio
frequenciesc. preamplifying the whole audio
bandd. converting the phase modulation
to FM
7. A pre-emphasis circuit provides extra noise immunity by
a. boosting the bass frequencyb. amplifying the high audio
frequenciesc. preamplifying the whole audio
bandd. converting the phase modulation
to FM
8. Since noise phase modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude
a. remains constantb. is decreasedc. is increasedd. is equalized
8. Since noise phase modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude
a. remains constantb. is decreasedc. is increasedd. is equalized
9. When the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. The modulation system is
a. amplitude modulationb. phase modulationc. frequency modulationd. any one of the three
9. When the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. The modulation system is
a. amplitude modulationb. phase modulationc. frequency modulationd. any one of the three
10. Indicate which one of the following is not an advantage of FM over AM:
a. Better noise immunity is provided
b. Lower bandwidth is requiredc. The transmitted power is more
usefuld. Less modulating power is
required
10. Indicate which one of the following is not an advantage of FM over AM:
a. Better noise immunity is provided
b. Lower bandwidth is requiredc. The transmitted power is more
usefuld. Less modulating power is
required
11. One of the following is an in direct way of generating FM. This is the
a. Reactance FET modulatorb. Varactor diodec. Armstrong modulatord. Reactance bipolar transistor
modulator
11. One of the following is an in direct way of generating FM. This is the
a. Reactance FET modulatorb. Varactor diodec. Armstrong modulatord. Reactance bipolar transistor
modulator
12. In an FM stereo multiplex transmission, the
a. sum signal modulates the 19KHz sub carrier
b. difference signal modulates the 19KHz sub carrier
c. difference signal modulates the 38KHz sub carrier
d. difference signal modulates the 67KHz sub carrier
12. In an FM stereo multiplex transmission, the
a. sum signal modulates the 19KHz sub carrier
b. difference signal modulates the 19KHz sub carrier
c. difference signal modulates the 38KHz sub carrier
d. difference signal modulates the 67KHz sub carrier
CHAPTER 6: RADIO RECEIVERS
1. Indicate which of the following statement about the advantages of the phase discriminator over the slope detector is false:
a. much easier alignmentb. better linearityc. great limitingd. fewer tuned circuits
1. Indicate which of the following statement about the advantages of the phase discriminator over the slope detector is false:
a. much easier alignmentb. better linearityc. great limitingd. fewer tuned circuits
2. Show which of the following statement about the amplitude limiter is untrue:
a. the circuit is always biased in class C, by the virtue of the leak type bias
b. when the input increases past the threshold of limiting, the gain decreases to keep the output constant
c. the output must be tunedd. leak type biased must be used
2. Show which of the following statement about the amplitude limiter is untrue:
a. the circuit is always biased in class C, by the virtue of the leak type bias
b. when the input increases past the threshold of limiting, the gain decreases to keep the output constant
c. the output must be tunedd. leak type biased must be used
3. In a radio receiver with simple AGC
a. an increase in signal strength produces more AGC
b. the audio stage gain is normally controlled by the AGC
c. the faster the AGC time constant, the more accurate the output
d. the highest AGC voltage is produced between stations
3. In a radio receiver with simple AGC
a. an increase in signal strength produces more AGC
b. the audio stage gain is normally controlled by the AGC
c. the faster the AGC time constant, the more accurate the output
d. the highest AGC voltage is produced between stations
4. In broadcast super heterodyne receiver, the
a. local oscillator operates below the signal frequency
b. mixer input must be tuned to the signal frequency
c. local oscillator frequency is normally double the IF
d. RF amplifier normally works at 455KHz above the carrier frequency
4. In broadcast super heterodyne receiver, the
a. local oscillator operates below the signal frequency
b. mixer input must be tuned to the signal frequency
c. local oscillator frequency is normally double the IF
d. RF amplifier normally works at 455KHz above the carrier frequency
5. To prevent overloading of the last IF amplifier in the receiver, one should use
a. squelchb. variable sensitivityc. variable selectivityd. double conversion
5. To prevent overloading of the last IF amplifier in the receiver, one should use
a. squelchb. variable sensitivityc. variable selectivityd. double conversion
6. A super heterodyne receiver with an IF of 450KHz is tuned to a signal at 1200KHz. The image frequency is
a. 750KHzb. 900KHzc. 1650KHzd. 2100KHz
6. A super heterodyne receiver with an IF of 450KHz is tuned to a signal at 1200KHz. The image frequency is
a. 750KHzb. 900KHzc. 1650KHzd. 2100KHz
7. In a radio detectora. the linearity is worse than in
phase discriminatorb. stabilization against signal
strength variations is providedc. the output is twice that
obtainable from a similar phase discriminator
d. the circuit is the same as in a discriminator, except that the diodes are reversed
7. In a radio detectora. the linearity is worse than in
phase discriminatorb. stabilization against signal
strength variations is providedc. the output is twice that
obtainable from a similar phase discriminator
d. the circuit is the same as in a discriminator, except that the diodes are reversed
8. The typical squelch circuit cuts off
a. an audio amplifier when the carrier is absent
b. RF interference when the signal is weak
c. an IF amplifier when the AGC is maximum
d. an IF amplifier when the AGC is minimum
8. The typical squelch circuit cuts off
a. an audio amplifier when the carrier is absent
b. RF interference when the signal is weak
c. an IF amplifier when the AGC is maximum
d. an IF amplifier when the AGC is minimum
9. Indicate the false statement in connection with the communications receivers.
a. The noise limiter cuts off the receiver’s output during a noise pulse.
b. A product demodulator could be used for the reception of morse code
c. Double conversion is used to improve image rejection
d. Variable sensitivity is used to eliminate selective fading
9. Indicate the false statement in connection with the communications receivers.
a. The noise limiter cuts off the receiver’s output during a noise pulse.
b. A product demodulator could be used for the reception of morse code
c. Double conversion is used to improve image rejection
d. Variable sensitivity is used to eliminate selective fading
10. The controlled oscillator synthesizer is sometimes preferred to the direct one because
a. it is simpler piece of equipmentb. its frequency stability is betterc. it does not require crystal
oscillatorsd. it is relatively free of spurious
frequencies
10. The controlled oscillator synthesizer is sometimes preferred to the direct one because
a. it is simpler piece of equipmentb. its frequency stability is betterc. it does not require crystal
oscillatorsd. it is relatively free of spurious
frequencies
11. The frequency generated by each decade in a direct frequency synthesizer is much higher than the frequency shown; this is done to
a. reduce the spurious frequency problem
b. increase the frequency stability of the synthesizer
c. reduce the number of decadesd. reduce the number of crystal
required
11. The frequency generated by each decade in a direct frequency synthesizer is much higher than the frequency shown; this is done to
a. reduce the spurious frequency problem
b. increase the frequency stability of the synthesizer
c. reduce the number of decadesd. reduce the number of crystal
required
12. Indicated which of the following circuits could not demodulate SSB.
a. Balance modulatorb. Product detectorc. BFOd. Phase discriminator
12. Indicated which of the following circuits could not demodulate SSB.
a. Balance modulatorb. Product detectorc. BFOd. Phase discriminator
13. If an FET is used as the first AF amplifier in a transistor receiver, this will have the effect of
a. improving the effectiveness of the AGC
b. reducing the effect of negative peak clipping
c. reducing the effect of noise at low modulation depths
d. improving the selectivity of the receiver
13. If an FET is used as the first AF amplifier in a transistor receiver, this will have the effect of
a. improving the effectiveness of the AGC
b. reducing the effect of negative peak clipping
c. reducing the effect of noise at low modulation depths
d. improving the selectivity of the receiver
14. Indicate the false statement. The super heterodyne receiver replaced the TRF receiver because the latter suffered from
a. gain variation over the frequency coverage range
b. insufficient gain and sensitivityc. inadequate selectivity at high
frequenciesd. instability
14. Indicate the false statement. The super heterodyne receiver replaced the TRF receiver because the latter suffered from
a. gain variation over the frequency coverage range
b. insufficient gain and sensitivityc. inadequate selectivity at high
frequenciesd. instability
15. The image frequency of a super heterodyne 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 the receiver is tuned
15. The image frequency of a super heterodyne 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 the receiver is tuned
16. One of the main functions of the RF amplifier in a super heterodyne receiver is to
a. provide improved trackingb. permit better adjacent-channel
rejectionc. increase the tuning range of the
receiverd. improve the rejection of the image
frequency
16. One of the main functions of the RF amplifier in a super heterodyne receiver is to
a. provide improved trackingb. permit better adjacent-channel
rejectionc. increase the tuning range of the
receiverd. improve the rejection of the image
frequency
17. A receiver has poor IF selectivity. It will therefore also have poor
a. blockingb. double spottingc. diversity receptiond. sensitivity
17. A receiver has poor IF selectivity. It will therefore also have poor
a. blockingb. double spottingc. diversity receptiond. sensitivity
18. Three point tracking is achieved with
a. variable selectivityb. the padder capacitorc. double spottingd. double conversion
18. Three point tracking is achieved with
a. variable selectivityb. the padder capacitorc. double spottingd. double conversion
19. The local oscillator of a broadcast receiver is tuned to a frequency higher that the incoming frequency
a. to help the image frequency rejection
b. to permit easier trackingc. because otherwise an
intermediate frequency could not be produced
d. to allow adequate frequency coverage without switching
19. The local oscillator of a broadcast receiver is tuned to a frequency higher that the incoming frequency
a. to help the image frequency rejection
b. to permit easier trackingc. because otherwise an
intermediate frequency could not be produced
d. to allow adequate frequency coverage without switching
20. If the intermediate frequency is very high (indicate the false statement)
a. image frequency rejection is very good
b. the local oscillator need to be extremely stable
c. the selectivity will be poord. tracking will be improved
20. If the intermediate frequency is very high (indicate the false statement)
a. image frequency rejection is very good
b. the local oscillator need to be extremely stable
c. the selectivity will be poord. tracking will be improved
21. A low ratio of the AC to the DC load impedance of a diode detector results in
a. diagonal clippingb. poor AGC operationc. negative-peak clippingd. poor AF response
21. A low ratio of the AC to the DC load impedance of a diode detector results in
a. diagonal clippingb. poor AGC operationc. negative-peak clippingd. poor AF response
22. One of the following cannot be used to demodulate SSB.
a. product detectorb. diode balance modulatorc. bipolar transistor balance
modulatord. complete phase-shift generator
22. One of the following cannot be used to demodulate SSB.
a. product detectorb. diode balance modulatorc. bipolar transistor balance
modulatord. complete phase-shift generator
23. Indicate the false statement. Noting that no carrier is transmitted with J3E, we see that
a. the receiver cannot use a phase comparator for AFC
b. adjacent-channel rejection is more difficult
c. production of AGC is rather complicated process
d. the transmission is not compatible with A3E
23. Indicate the false statement. Noting that no carrier is transmitted with J3E, we see that
a. the receiver cannot use a phase comparator for AFC
b. adjacent-channel rejection is more difficult
c. production of AGC is rather complicated process
d. the transmission is not compatible with A3E
24. When the receiver has good blocking performance, this means that
a. it does not suffer from double spotting
b. its image frequency rejection is poor
c. it is unaffected by AGC derived from nearby transmission
d. its detector suffers from burnout
24. When the receiver has good blocking performance, this means that
a. it does not suffer from double spotting
b. its image frequency rejection is poor
c. it is unaffected by AGC derived from nearby transmission
d. its detector suffers from burnout
25. An AM receiver uses a diode detector to demodulation. This enables it satisfactorily to receive
a. single sideband, suppressed carrier
b. single sideband, reduced carrierc. ISBd. Single sideband, full carrier
25. An AM receiver uses a diode detector to demodulation. This enables it satisfactorily to receive
a. single sideband, suppressed carrier
b. single sideband, reduced carrierc. ISBd. Single sideband, full carrier
CHAPTER 7: TRANSMISSION LINES
1. Indicate the false statement. The SWR on a transmission line infinity; the line is terminated in
a. a short circuitb. a complex impedancec. an open circuitd. a pure resistance
1. Indicate the false statement. The SWR on a transmission line infinity; the line is terminated in
a. a short circuitb. a complex impedancec. an open circuitd. a pure resistance
2. A (75 - j50) load is connected to a coaxial transmission line of Zo = 75, at 10GHz. The best method of matching consists in connecting
a. a short circuited stub at the loadb. an inductance at the loadc. a capacitance at some specific
distance from the loadd. a short circuited stub at some
specific distance from the load
2. A (75 - j50) load is connected to a coaxial transmission line of Zo = 75, at 10GHz. The best method of matching consists in connecting
a. a short circuited stub at the loadb. an inductance at the loadc. a capacitance at some specific
distance from the loadd. a short circuited stub at some
specific distance from the load
3. The velocity factor of a transmission line
a. depends on the dielectric constant of the material used
b. increase the velocity along the transmission line
c. is governed by the skin effectd. is higher for a solid dielectric
than for air
3. The velocity factor of a transmission line
a. depends on the dielectric constant of the material used
b. increase the velocity along the transmission line
c. is governed by the skin effectd. is higher for a solid dielectric
than for air
4. Impedance inversion may be obtained with
a. a short circuited stubb. an open circuited stubc. a quarter wave lined. a half wave line
4. Impedance inversion may be obtained with
a. a short circuited stubb. an open circuited stubc. a quarter wave lined. a half wave line
5. Short-circuited stubs are preferred to open circuited stub because the latter are
a. more difficult to make and connect
b. made of transmission line with a different characteristic impedance
c. liable to radiated. incapable of giving a full range of
reactance
5. Short-circuited stubs are preferred to open circuited stub because the latter are
a. more difficult to make and connect
b. made of transmission line with a different characteristic impedance
c. liable to radiated. incapable of giving a full range of
reactance
6. For a transmission line load matching over a range of frequencies, it is best to use a
a. balunb. broadband directional couplerc. double stubd. single stud of adjustable position
6. For a transmission line load matching over a range of frequencies, it is best to use a
a. balunb. broadband directional couplerc. double stubd. single stud of adjustable position
7. The main disadvantage of the two hole directional coupler is
a. low directional couplingb. poor directivityc. high SWRd. narrow bandwidth
7. The main disadvantage of the two hole directional coupler is
a. low directional couplingb. poor directivityc. high SWRd. narrow bandwidth
8. To couple a coaxial line to a parallel wire, it is best to use a
a. slotted lineb. balunc. directional couplerd. quarter wave transformer
8. To couple a coaxial line to a parallel wire, it is best to use a
a. slotted lineb. balunc. directional couplerd. quarter wave transformer
9. Indicate the three types of transmission line energy losses
a. (I^2)R, RL, and temperatureb. Radiation, (I^2)R, and dielectric
heatingc. Dielectric separation, insulation
breakdown, and radiationd. Conductor heating, dielectric
heating, and radiation resistance
9. Indicate the three types of transmission line energy losses
a. (I^2)R, RL, and temperatureb. Radiation, (I^2)R, and dielectric
heatingc. Dielectric separation, insulation
breakdown, and radiationd. Conductor heating, dielectric
heating, and radiation resistance
10. Indicate the true statement below. The directional coupler is
a. A device used to connect a transmitter to a directional antenna
b. A coupling device for matching impedance
c. A device used to measure transmission line power
d. An SWR measuring instrument
10. Indicate the true statement below. The directional coupler is
a. A device used to connect a transmitter to a directional antenna
b. A coupling device for matching impedance
c. A device used to measure transmission line power
d. An SWR measuring instrument
CHAPTER 8: RADIATION AND PROPAGATION OF WAVES
1. Indicated which one of the following terms applies to troposcatter propagation:
a. SIDsb. Fadingc. Atmospheric stormsd. Faraday Rotation
1. Indicated which one of the following terms applies to troposcatter propagation:
a. SIDsb. Fadingc. Atmospheric stormsd. Faraday Rotation
2. VLF waves are used for some types of services because
a. of the low powers requiredb. the transmitting antennas are of
convenient sizec. they are very reliabled. they penetrate the ionosphere
easily
2. VLF waves are used for some types of services because
a. of the low powers requiredb. the transmitting antennas are of
convenient sizec. they are very reliabled. they penetrate the ionosphere
easily
3. Indicate which of the following frequencies cannot be used for reliable beyond the horizon terrestrial communication without repeaters
a. 20KHzb. 15MHzc. 900MHzd. 12GHz
3. Indicate which of the following frequencies cannot be used for reliable beyond the horizon terrestrial communication without repeaters
a. 20KHzb. 15MHzc. 900MHzd. 12GHz
4. High frequency waves area. absorbed by the F2 layerb. reflected by the D layerc. capable of use for long distance
communication on the moond. affected by the solar cycle
4. High frequency waves area. absorbed by the F2 layerb. reflected by the D layerc. capable of use for long distance
communication on the moond. affected by the solar cycle
5. Distances near the skip distance should be used for the sky-wave propagation
a. to avoid tiltingb. to prevent sky-wave and upper
ray interferencec. to avoid the Faraday effectd. so as not to exceed the critical
frequency
5. Distances near the skip distance should be used for the sky-wave propagation
a. to avoid tiltingb. to prevent sky-wave and upper
ray interferencec. to avoid the Faraday effectd. so as not to exceed the critical
frequency
6. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of
a. a more directional antennasb. broadband antennasc. frequency diversityd. space diversity
6. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of
a. a more directional antennasb. broadband antennasc. frequency diversityd. space diversity
7. A range of microwave frequency more easily passed by the atmosphere than the other is called a
a. windowb. critical frequencyc. gyro frequency ranged. Resonance in the atmosphere
7. A range of microwave frequency more easily passed by the atmosphere than the other is called a
a. windowb. critical frequencyc. gyro frequency ranged. Resonance in the atmosphere
8. Frequencies in the UHF range normally propagate by means of
a. ground wavesb. sky wavesc. surface wavesd. space waves
8. Frequencies in the UHF range normally propagate by means of
a. ground wavesb. sky wavesc. surface wavesd. space waves
9. Tropospheric scatter is used with frequencies in the following range
a. HFb. VHFc. UHFd. VLF
9. Tropospheric scatter is used with frequencies in the following range
a. HFb. VHFc. UHFd. VLF
10. The ground wave eventually disappears, as one moves away from the transmitter, because of
a. interference from the sky waveb. loss of line of sight conditionsc. maximum single hop distance
limitationsd. tilting
10. The ground wave eventually disappears, as one moves away from the transmitter, because of
a. interference from the sky waveb. loss of line of sight conditionsc. maximum single hop distance
limitationsd. tilting
11. In electromagnetic waves, polarization
a. is caused by reflectionb. is due to the transverse nature of
the wavesc. results from the longitudinal
nature of wavesd. is always vertical in an isotropic
antenna
11. In electromagnetic waves, polarization
a. is caused by reflectionb. is due to the transverse nature of
the wavesc. results from the longitudinal
nature of wavesd. is always vertical in an isotropic
antenna
12. As electromagnetic waves travel in free space, one the following can happen to them:
a. absorptionb. attenuationc. refractiond. reflection
12. As electromagnetic waves travel in free space, one the following can happen to them:
a. absorptionb. attenuationc. refractiond. reflection
13. The absorption of radio waves by the atmosphere depends on
a. their frequencyb. their distance from the
transmitterc. the polarization of the wavesd. the polarization of the
atmosphere
13. The absorption of radio waves by the atmosphere depends on
a. their frequencyb. their distance from the
transmitterc. the polarization of the wavesd. the polarization of the
atmosphere
14. Electromagnetic waves are refracted when they
a. pass into a medium of different dielectric constant
b. are polarized at right angles to the direction of propagation
c. encounter a perfectly conducting surface
d. pass through small slot in a conducting plane
14. Electromagnetic waves are refracted when they
a. pass into a medium of different dielectric constant
b. are polarized at right angles to the direction of propagation
c. encounter a perfectly conducting surface
d. pass through small slot in a conducting plane
15. Diffraction of electromagnetic wave
a. is caused by reflections from the ground
b. arises only with the spherical wave fronts
c. will occur when the waves pass through a large slot
d. may occur around the edge of a sharp obstacle
15. Diffraction of electromagnetic wave
a. is caused by reflections from the ground
b. arises only with the spherical wave fronts
c. will occur when the waves pass through a large slot
d. may occur around the edge of a sharp obstacle
16. When microwave signals follow the curvature of the earth, this is known as
a. the Faraday effectb. ductingc. troposheric scatterd. ionospheric reflections
16. When microwave signals follow the curvature of the earth, this is known as
a. the Faraday effectb. ductingc. troposheric scatterd. ionospheric reflections
17. Helical antennas are often used for satellite tracking at VHF because of
a. troposcatterb. superrefractionc. ionospheric refractiond. the Faraday effect
17. Helical antennas are often used for satellite tracking at VHF because of
a. troposcatterb. superrefractionc. ionospheric refractiond. the Faraday effect
CHAPTER 9: ANTENNAS
1. An ungrounded antenna near the ground
a. acts a single antenna of twice the height
b. is unlikely need an earth matc. acts as an antenna arrayd. must be horizontally polarized
1. An ungrounded antenna near the ground
a. acts a single antenna of twice the height
b. is unlikely need an earth matc. acts as an antenna arrayd. must be horizontally polarized
2. One of the following consist of non resonant antenna
a. rhombic antennab. folded dipolec. end fire arrayd. broadside array
2. One of the following consist of non resonant antenna
a. rhombic antennab. folded dipolec. end fire arrayd. broadside array
3. One of the following is very useful as a multiband HF receiving antenna. This is the
a. conical hornb. folded dipolec. log-periodicd. square loop
3. One of the following is very useful as a multiband HF receiving antenna. This is the
a. conical hornb. folded dipolec. log-periodicd. square loop
4. Which of the following antenna is best excited from a waveguide?
a. biconicalb. hornc. helicald. discone
4. Which of the following antenna is best excited from a waveguide?
a. biconicalb. hornc. helicald. discone
5. Indicate which of the following reasons for using a counter poise with antenna is false
a. impossibility of a good ground connection
b. protection of personnel working underground
c. provision of an earth for the antenna
d. rockiness of the ground itself
5. Indicate which of the following reasons for using a counter poise with antenna is false
a. impossibility of a good ground connection
b. protection of personnel working underground
c. provision of an earth for the antenna
d. rockiness of the ground itself
6. One of the following is not a reason for the use of an antenna coupler:
a. to make the antenna look resistive
b. to provide the output amplifier with the correct load impedance
c. to discriminate against harmonics
d. to prevent reradiation of the local oscillator
6. One of the following is not a reason for the use of an antenna coupler:
a. to make the antenna look resistive
b. to provide the output amplifier with the correct load impedance
c. to discriminate against harmonics
d. to prevent reradiation of the local oscillator
7. Indicate the antenna that is not wideband:
a. Disconeb. Folded dipolec. Helicald. Marconi
7. Indicate the antenna that is not wideband:
a. Disconeb. Folded dipolec. Helicald. Marconi
8. Indicate which of the following reasons for use of an earth mat with antennas is false:
a. impossibility of a good ground connection
b. provision of an earth for the antennac. protection of personnel working
underneathd. improvement of radiation pattern of
the antenna
8. Indicate which of the following reasons for use of an earth mat with antennas is false:
a. impossibility of a good ground connection
b. provision of an earth for the antennac. protection of personnel working
underneathd. improvement of radiation pattern of
the antenna
9. Which one of the following terms does not apply the yagi-uda array?
a. good bandwidthb. parasitic elementsc. folded dipoled. high gain
9. Which one of the following terms does not apply the yagi-uda array?
a. good bandwidthb. parasitic elementsc. folded dipoled. high gain
10. An antenna that is circularly polarized is the
a. helicalb. small circular loopc. parabolic reflectord. yagi–uda
10. An antenna that is circularly polarized is the
a. helicalb. small circular loopc. parabolic reflectord. yagi–uda
11. The standard reference antenna for the directive gain is the
a. infinitesimal dipoleb. isotropic antennac. elementary doubletd. half wave dipole
11. The standard reference antenna for the directive gain is the
a. infinitesimal dipoleb. isotropic antennac. elementary doubletd. half wave dipole
12. Top loading is sometimes used with an antenna in order to increase its
a. effective heightb. bandwidthc. beam widthd. input capacitance
12. Top loading is sometimes used with an antenna in order to increase its
a. effective heightb. bandwidthc. beam widthd. input capacitance
13. Cassegrain feed is used with a parabolic reflector to
a. increase the gain of the systemb. increase the beam width of the
systemc. reduce the size of the main
reflectord. allow the feed to be placed at a
convenient point
13. Cassegrain feed is used with a parabolic reflector to
a. increase the gain of the systemb. increase the beam width of the
systemc. reduce the size of the main
reflectord. allow the feed to be placed at a
convenient point
14. Zoning is used with a dielectric antenna in order to
a. reduce the bulk of the lensb. increase the bandwidth of the
lensc. permit pin point focusingd. correct the curvature of the wave
front from a horn that is too short
14. Zoning is used with a dielectric antenna in order to
a. reduce the bulk of the lensb. increase the bandwidth of the
lensc. permit pin point focusingd. correct the curvature of the wave
front from a horn that is too short
15. Helical antenna is used for satellite tracking because of its
a. circular polarizationb. maneuverabilityc. broad bandwidthd. good front to back ratio
15. Helical antenna is used for satellite tracking because of its
a. circular polarizationb. maneuverabilityc. broad bandwidthd. good front to back ratio
16. The discone antenna isa. a useful direction finding
antennab. used as a radar receiving
antennac. circularly polarized like other
circular antennasd. useful as a UHF receiving
antenna
16. The discone antenna isa. a useful direction finding
antennab. used as a radar receiving
antennac. circularly polarized like other
circular antennasd. useful as a UHF receiving
antenna
17. One of the following is not an omni directional antenna
a. Half wave dipoleb. Log periodicc. Disconed. Marconi
17. One of the following is not an omni directional antenna
a. Half wave dipoleb. Log periodicc. Disconed. Marconi
CHAPTER 10: WAVEGUIDES, RESONATORS and COMPONENTS
1. When electromagnetic waves are propagated in a wave guide
a. they travel along the broader walls of the guide
b. they are reflected from the walls but do not travel along them
c. they travel through the dielectric without touching the walls
d. they travel along all four walls of the waveguide
1. When electromagnetic waves are propagated in a wave guide
a. they travel along the broader walls of the guide
b. they are reflected from the walls but do not travel along them
c. they travel through the dielectric without touching the walls
d. they travel along all four walls of the waveguide
2. Waveguides are used mainly for microwave signals because
a. the depend on the straight line propagation which applies to microwaves only
b. losses would be to heavy at lower frequencies
c. there are no generators powerful enough to excite them at lower frequencies
d. they would be too bulky at lower frequencies
2. Waveguides are used mainly for microwave signals because
a. the depend on the straight line propagation which applies to microwaves only
b. losses would be to heavy at lower frequencies
c. there are no generators powerful enough to excite them at lower frequencies
d. they would be too bulky at lower frequencies
3. The wavelength of a wave in a waveguide
a. is greater than in free spaceb. depends only on the wave guide
dimensions and the free space wavelength
c. is inversely proportional to the phase velocity
d. is directly proportional to the group velocity
3. The wavelength of a wave in a waveguide
a. is greater than in free spaceb. depends only on the wave guide
dimensions and the free space wavelength
c. is inversely proportional to the phase velocity
d. is directly proportional to the group velocity
4. The main difference between the operation of transmission lines and wave guides is that
a. the latter are not distributed, like transmission lines
b. the former can use stubs and quarter wave transformers, unlike the latter
c. transmission lines use the principal mode of propagation, and therefore do not suffer from low frequency cut off
d. terms such as impedance matching and standing wave ration cannot be applied to waveguides
4. The main difference between the operation of transmission lines and wave guides is that
a. the latter are not distributed, like transmission lines
b. the former can use stubs and quarter wave transformers, unlike the latter
c. transmission lines use the principal mode of propagation, and therefore do not suffer from low frequency cut off
d. terms such as impedance matching and standing wave ration cannot be applied to waveguides
5. Compared with the equivalent transmission line, 3GHz waveguides (indicate the false statement)
a. are less lossyb. can carry high powersc. are less bulkyd. have lower attenuation
5. Compared with the equivalent transmission line, 3GHz waveguides (indicate the false statement)
a. are less lossyb. can carry high powersc. are less bulkyd. have lower attenuation
6. When a particular mode is excited in a waveguide, there appears an extra electric component, in the direction of propagation. The resulting mode is
a. transverse-electricb. transverse-magneticc. longitudinald. transverse-electromagnetic
6. When a particular mode is excited in a waveguide, there appears an extra electric component, in the direction of propagation. The resulting mode is
a. transverse-electricb. transverse-magneticc. longitudinald. transverse-electromagnetic
7. When electromagnetic waves are reflected at an angle from a wall, their wave length along the wall is
a. the same as in free spaceb. the same as the wavelength
perpendicular to the wallc. shortened because of the
Doppler effectd. greater than in the actual
direction of propagation
7. When electromagnetic waves are reflected at an angle from a wall, their wave length along the wall is
a. the same as in free spaceb. the same as the wavelength
perpendicular to the wallc. shortened because of the
Doppler effectd. greater than in the actual
direction of propagation
8. As a result of reflections from a plane conducting wall, electromagnetic waves require an apparent velocity greater than the velocity of light in space. This is called
a. velocity of propagationb. normal velocityc. group velocityd. phase velocity
8. As a result of reflections from a plane conducting wall, electromagnetic waves require an apparent velocity greater than the velocity of light in space. This is called
a. velocity of propagationb. normal velocityc. group velocityd. phase velocity
9. Indicate the false statement. When the free space wavelength of a signal equals the cutoff waveguide of the guide
a. the group velocity of the signal becomes zero
b. the phase velocity of the signal becomes infinite
c. the characteristic impedance of the guide becomes infinite
d. the wavelength within the wave guide becomes infinite
9. Indicate the false statement. When the free space wavelength of a signal equals the cutoff waveguide of the guide
a. the group velocity of the signal becomes zero
b. the phase velocity of the signal becomes infinite
c. the characteristic impedance of the guide becomes infinite
d. the wavelength within the wave guide becomes infinite
10. A signal propagated in a waveguide has a full wave of electric intensity change between the two further walls, and no component of the electric field in the direction of propagation. The mode is
a. TE 1,1b. TE 1,0c. TM 2,2d. TE 2,0
10. A signal propagated in a waveguide has a full wave of electric intensity change between the two further walls, and no component of the electric field in the direction of propagation. The mode is
a. TE 1,1b. TE 1,0c. TM 2,2d. TE 2,0
11. The dominant mode of propagation is preferred with rectangular waveguides because (false)
a. it leads to the smallest waveguide dimensions
b. the resulting impedance can be matched directly to coaxial lines
c. its is easier to excite than the other modes
d. propagation of it without any spurious generation can be ensured
11. The dominant mode of propagation is preferred with rectangular waveguides because (false)
a. it leads to the smallest waveguide dimensions
b. the resulting impedance can be matched directly to coaxial lines
c. its is easier to excite than the other modes
d. propagation of it without any spurious generation can be ensured
12. A choke flange may be used to couple two waveguides
a. to help in alignment of the waveguides
b. because it is simplier than any other join
c. to compensate for discontinuities at the join
d. to increase the bandwidth of the system
12. A choke flange may be used to couple two waveguides
a. to help in alignment of the waveguides
b. because it is simplier than any other join
c. to compensate for discontinuities at the join
d. to increase the bandwidth of the system
13. In order to couple two generators to a waveguide system without coupling them to each other, one could not use a
a. rat raceb. E – plane Tc. Hybrid ringd. Magic T
13. In order to couple two generators to a waveguide system without coupling them to each other, one could not use a
a. rat raceb. E – plane Tc. Hybrid ringd. Magic T
14. Which of the following waveguide tuning components is not easily adjustable?
a. screwb. stubc. irisd. plunger
14. Which of the following waveguide tuning components is not easily adjustable?
a. screwb. stubc. irisd. plunger
15. A piston attenuator is aa. vane attenuatorb. waveguide below cutoffc. mode filterd. flap attenuator
15. A piston attenuator is aa. vane attenuatorb. waveguide below cutoffc. mode filterd. flap attenuator
16. Cylindrical cavity resonators are not used with klystrons because they have
a. a Q that is too lowb. a shape whose resonant
frequency is too difficult to calculate
c. harmonically related resonant frequencies
d. too heavy losses
16. Cylindrical cavity resonators are not used with klystrons because they have
a. a Q that is too lowb. a shape whose resonant
frequency is too difficult to calculate
c. harmonically related resonant frequencies
d. too heavy losses
17. A directional coupler with three or more holes is sometimes used in preference to the two hole coupler
a. because it is more efficientb. to increase coupling of the signalc. to reduce spurious mode
generationd. to increase the bandwidth of the
system
17. A directional coupler with three or more holes is sometimes used in preference to the two hole coupler
a. because it is more efficientb. to increase coupling of the signalc. to reduce spurious mode
generationd. to increase the bandwidth of the
system
18. A ferrite isa. a non conductor with magnetic
propertiesb. an intermetallic compound with
particularly good conductivityc. an insulator which heavily
attenuates magnetic fieldsd. a microwave semiconductor
invented by faraday
18. A ferrite isa. a non conductor with magnetic
propertiesb. an intermetallic compound with
particularly good conductivityc. an insulator which heavily
attenuates magnetic fieldsd. a microwave semiconductor
invented by faraday
19. Manganese ferrite may be used as a (false)
a. circulatorb. isolatorc. garnetd. phase shifter
19. Manganese ferrite may be used as a (false)
a. circulatorb. isolatorc. garnetd. phase shifter
20. The maximum power that may be handled by a ferrite component is limited by the
a. curie temperatureb. saturation magnetizationc. line widthd. gyromagnetic resonance
20. The maximum power that may be handled by a ferrite component is limited by the
a. curie temperatureb. saturation magnetizationc. line widthd. gyromagnetic resonance
21. A PIN diode isa. a metal semiconductor point
contact diodeb. a microwave mixer diodec. often used as a microwave
detectord. suitable for the use as a
microwave switch
21. A PIN diode isa. a metal semiconductor point
contact diodeb. a microwave mixer diodec. often used as a microwave
detectord. suitable for the use as a
microwave switch
22. A duplexer is useda. to couple two different antennas to a
transmitter with out mutual interference
b. to allow the one antenna to be used for reception or transmission without mutual interference
c. To prevent interference between two antennas when they are connected to a receiver
d. to increase the speed of the pulses in pulsed radar
22. A duplexer is useda. to couple two different antennas to a
transmitter with out mutual interference
b. to allow the one antenna to be used for reception or transmission without mutual interference
c. To prevent interference between two antennas when they are connected to a receiver
d. to increase the speed of the pulses in pulsed radar
23. For some applications, circular waveguides may be preferred to rectangular ones because of
a. smaller cross section needed at any frequency
b. lower attenuationc. freedom from spurious modesd. rotation of polarization
23. For some applications, circular waveguides may be preferred to rectangular ones because of
a. smaller cross section needed at any frequency
b. lower attenuationc. freedom from spurious modesd. rotation of polarization
24. Indicate which of the following cannot be followed by the word “waveguide”:
a. Ellipticalb. Flexiblec. Coaxiald. Ridged
24. Indicate which of the following cannot be followed by the word “waveguide”:
a. Ellipticalb. Flexiblec. Coaxiald. Ridged
25. In order to reduce cross sectional dimensions, the waveguide to use is
a. circularb. ridgedc. rectangulard. flexible
25. In order to reduce cross sectional dimensions, the waveguide to use is
a. circularb. ridgedc. rectangulard. flexible
26. For low attenuation, the best transmission medium is
a. flexible waveguideb. ridged waveguidec. rectangular waveguided. coaxial line
26. For low attenuation, the best transmission medium is
a. flexible waveguideb. ridged waveguidec. rectangular waveguided. coaxial line
CHAPTER 11: MICROWAVE TUBES AND CIRCUITS
1. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the
a. reflex klystronb. coaxial magnetronc. traveling wave tube magnetrond. CFA
1. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the
a. reflex klystronb. coaxial magnetronc. traveling wave tube magnetrond. CFA
2. One of the following is unlikely to be used as a pulsed device. It is the
a. multicavityb. BWOc. CFAd. TWT
2. One of the following is unlikely to be used as a pulsed device. It is the
a. multicavityb. BWOc. CFAd. TWT
3. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their
a. noise figure increasesb. transit time becomes to shortc. shunt capacitive reactance
becomes too larged. series inductive reactance
becomes too small
3. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their
a. noise figure increasesb. transit time becomes to shortc. shunt capacitive reactance
becomes too larged. series inductive reactance
becomes too small
4. Indicate the false statement. Transit time in microwave tubes will be reduced if
a. the electrodes are brought closer together
b. a higher anode current is usedc. multiple or coaxial leads are
usedd. the anode voltage is made larger
4. Indicate the false statement. Transit time in microwave tubes will be reduced if
a. the electrodes are brought closer together
b. a higher anode current is usedc. multiple or coaxial leads are
usedd. the anode voltage is made larger
5. The Multicavity klystrona. is not a good low level amplifier
because of noiseb. has a high repeller voltage to
ensure a rapid transit timec. is not suitable for pulsed
operationd. needs a long transit time through
the buncher cavity to ensure current modulation
5. The Multicavity klystrona. is not a good low level amplifier
because of noiseb. has a high repeller voltage to
ensure a rapid transit timec. is not suitable for pulsed
operationd. needs a long transit time through
the buncher cavity to ensure current modulation
6. Indicate the false statement. Klystron may use intermediate cavities to
a. prevent the oscillations that occur in two cavity klystron
b. increase the bandwidth of the device
c. improve the power gaind. increase the efficiency of the
klystron
6. Indicate the false statement. Klystron may use intermediate cavities to
a. prevent the oscillations that occur in two cavity klystron
b. increase the bandwidth of the device
c. improve the power gaind. increase the efficiency of the
klystron
7. The TWT is sometimes preferred to the multicavity klystron amplifier, because the former
a. is more efficientb. has a greater bandwidthc. has a higher number of modesd. produces a higher output power
7. The TWT is sometimes preferred to the multicavity klystron amplifier, because the former
a. is more efficientb. has a greater bandwidthc. has a higher number of modesd. produces a higher output power
8. The transit time in the repeller space of a reflex klystron must be n + ¾ cycles to ensure that
a. electrons are accelerated by the gap voltages on their return
b. returning electron give energy to gap oscillations
c. it is equal to the period of the cavity oscillations
d. the repeller is not damaged by the striking electrons
8. The transit time in the repeller space of a reflex klystron must be n + ¾ cycles to ensure that
a. electrons are accelerated by the gap voltages on their return
b. returning electron give energy to gap oscillations
c. it is equal to the period of the cavity oscillations
d. the repeller is not damaged by the striking electrons
9. The cavity magnetron uses strapping to
a. prevent mode jumpingb. prevent cathode back heatingc. ensure bunchingd. improve the phase focusing
effect
9. The cavity magnetron uses strapping to
a. prevent mode jumpingb. prevent cathode back heatingc. ensure bunchingd. improve the phase focusing
effect
10. Magnetic field is used in the cavity magnetron to
a. prevent anode current in absence of oscillations
b. ensure that the oscillations are pulsed
c. help in focusing the electron beam, thus preventing spreading
d. ensure electrons will orbit around the cathode
10. Magnetic field is used in the cavity magnetron to
a. prevent anode current in absence of oscillations
b. ensure that the oscillations are pulsed
c. help in focusing the electron beam, thus preventing spreading
d. ensure electrons will orbit around the cathode
11. To avoid difficulties with strapping at high frequencies, the type of cavity structure used in the magnetron is the
a. hole and slotb. slotc. vaned. rising sun
11. To avoid difficulties with strapping at high frequencies, the type of cavity structure used in the magnetron is the
a. hole and slotb. slotc. vaned. rising sun
12. The primary purpose of the helix in a traveling wave tube is to
a. prevent the electron beam from spreading in the long tube
b. reduce the axial velocity of the RF field
c. ensure broadband operationd. reduce noise figure
12. The primary purpose of the helix in a traveling wave tube is to
a. prevent the electron beam from spreading in the long tube
b. reduce the axial velocity of the RF field
c. ensure broadband operationd. reduce noise figure
13. The attenuator is used in the traveling wave tube to
a. help bunchingb. prevent oscillationsc. prevent saturationsd. increase gain
13. The attenuator is used in the traveling wave tube to
a. help bunchingb. prevent oscillationsc. prevent saturationsd. increase gain
14. Periodic permanent magnet focusing is used with TWTs to
a. allow pulsed operationb. improve electron bunchingc. avoid the bulk of an
electromagnetd. allow coupled cavity operation at
highest frequencies
14. Periodic permanent magnet focusing is used with TWTs to
a. allow pulsed operationb. improve electron bunchingc. avoid the bulk of an
electromagnetd. allow coupled cavity operation at
highest frequencies
15. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is
a. capable of longer duty cycleb. more efficient amplifierc. more broadbandd. less noisy
15. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is
a. capable of longer duty cycleb. more efficient amplifierc. more broadbandd. less noisy
16. Magnetron whose oscillating frequency is electronically adjustable over a wide range is called a
a. coaxial magnetronb. dither-tuned amplifierc. frequency- agile magnetrond. VTM
16. Magnetron whose oscillating frequency is electronically adjustable over a wide range is called a
a. coaxial magnetronb. dither-tuned amplifierc. frequency- agile magnetrond. VTM
17. Indicate which of the following is not TWT slow rate structure:
a. periodic permanent magnetb. coupled cavityc. helixd. ring bar
17. Indicate which of the following is not TWT slow rate structure:
a. periodic permanent magnetb. coupled cavityc. helixd. ring bar
18. The glass tube of a TWT may be coated with aquadag to
a. help focusingb. provide attenuationc. improve bunchingd. increase gain
18. The glass tube of a TWT may be coated with aquadag to
a. help focusingb. provide attenuationc. improve bunchingd. increase gain
19. Back ward wave oscillator is based on the
a. rising sun magnetronb. crossed field amplifierc. coaxial magnetrond. traveling wave tube
19. Back ward wave oscillator is based on the
a. rising sun magnetronb. crossed field amplifierc. coaxial magnetrond. traveling wave tube
CHAPTER 12: SEMICONDUCTOR MICROWAVE DEVICES ANDCIRCUITS
1. Parametric amplifier must be cooled
a. because parametric amplification generates a lot of heat
b. to increase bandwidthc. because it cannot operate at
room temperatured. to improve the noise
performance
1. Parametric amplifier must be cooled
a. because parametric amplification generates a lot of heat
b. to increase bandwidthc. because it cannot operate at
room temperatured. to improve the noise
performance
2. Ruby maser amplifier must be cooled
a. because maser amplification generates a lot of heat
b. to increase bandwidthc. because it cannot operate at
room temperatured. to improve the noise
performance
2. Ruby maser amplifier must be cooled
a. because maser amplification generates a lot of heat
b. to increase bandwidthc. because it cannot operate at
room temperatured. to improve the noise
performance
3. Disadvantage of microstrip compared with stripline is that microstrip
a. does not readily lend itself to printed circuit techniques
b. is more likely to radiatec. is bulkierd. is more expensive and complex
to manufacture
3. Disadvantage of microstrip compared with stripline is that microstrip
a. does not readily lend itself to printed circuit techniques
b. is more likely to radiatec. is bulkierd. is more expensive and complex
to manufacture
4. The transmission system using two ground planes is
a. microstripb. elliptical waveguidec. parallel wire lined. stripline
4. The transmission system using two ground planes is
a. microstripb. elliptical waveguidec. parallel wire lined. stripline
5. Indicate the false statement. An advantage of stripline over waveguides is its
a. smaller bulkb. greater bandwidthc. higher power handling capabilityd. greater compatibility with solid
state devices
5. Indicate the false statement. An advantage of stripline over waveguides is its
a. smaller bulkb. greater bandwidthc. higher power handling capabilityd. greater compatibility with solid
state devices
6. Indicate the false statement. An advantage of stripline over microstrip is its
a. easier integration with semiconductor devices
b. lower tendency to radiatec. higher isolation between
adjacent circuitsd. higher Q
6. Indicate the false statement. An advantage of stripline over microstrip is its
a. easier integration with semiconductor devices
b. lower tendency to radiatec. higher isolation between
adjacent circuitsd. higher Q
7. Surface acoustic waves propagate in
a. gallium arsenideb. indium phosphidec. striplined. quartz crystal
7. Surface acoustic waves propagate in
a. gallium arsenideb. indium phosphidec. striplined. quartz crystal
8. SAW devices may be used asa. transmission media like striplineb. filtersc. UHF amplifiersd. Oscillators at millimeter
frequencies
8. SAW devices may be used asa. transmission media like striplineb. filtersc. UHF amplifiersd. Oscillators at millimeter
frequencies
9. Indicate the false statement. FETs are preferred to bipolar transistor at the high frequencies because they
a. are less noisyb. lend themselves more readily to
integrationc. are capable of higher efficienciesd. can provide higher gains
9. Indicate the false statement. FETs are preferred to bipolar transistor at the high frequencies because they
a. are less noisyb. lend themselves more readily to
integrationc. are capable of higher efficienciesd. can provide higher gains
10. For best low level noise performance in the X-band, an amplifier should use
a. a bipolar transistorb. a Gunn diodec. a step-recovery dioded. an IMPATT diode
10. For best low level noise performance in the X-band, an amplifier should use
a. a bipolar transistorb. a Gunn diodec. a step-recovery dioded. an IMPATT diode
11. The biggest advantage of the TRAPATT diode over the IMPATT diode is its
a. low noiseb. higher efficiencyc. ability to operate at higher
frequenciesd. lesser sensitivity to harmonics
11. The biggest advantage of the TRAPATT diode over the IMPATT diode is its
a. low noiseb. higher efficiencyc. ability to operate at higher
frequenciesd. lesser sensitivity to harmonics
12. Indicate which of the following diodes will produce the highest pulsed power output
a. Varactorb. Gunnc. Schottky barrierd. RIMPATT
12. Indicate which of the following diodes will produce the highest pulsed power output
a. Varactorb. Gunnc. Schottky barrierd. RIMPATT
13. Indicate which of the following diodes does not use negative resistance in its operation:
a. Backwardb. Gunnc. IMPATTd. Tunnel
13. Indicate which of the following diodes does not use negative resistance in its operation:
a. Backwardb. Gunnc. IMPATTd. Tunnel
14. One of the following is not used as a microwave mixer or detector.
a. crystal diodeb. schottky barrier diodec. backward dioded. PIN diode
14. One of the following is not used as a microwave mixer or detector.
a. crystal diodeb. schottky barrier diodec. backward dioded. PIN diode
15. One of the following microwave diodes is suitable for very low power oscillations only:
a. tunnelb. avalanchec. Gunnd. IMPATT
15. One of the following microwave diodes is suitable for very low power oscillations only:
a. tunnelb. avalanchec. Gunnd. IMPATT
16. The transferred electron bulk effect occurs in
a. germaniumb. gallium arsenidec. silicond. metal semiconductor, junctions
16. The transferred electron bulk effect occurs in
a. germaniumb. gallium arsenidec. silicond. metal semiconductor, junctions
17. The gain bandwidth frequency of a microwave transistor, fT, is the frequency at which the
a. alpha of the transistor falls by 3dB
b. beta of the transistor falls by 3dBc. power gain of the transistor falls
to unityd. beta of the transistor falls to
unity
17. The gain bandwidth frequency of a microwave transistor, fT, is the frequency at which the
a. alpha of the transistor falls by 3dB
b. beta of the transistor falls by 3dBc. power gain of the transistor falls
to unityd. beta of the transistor falls to
unity
18. For microwave transistor to operate at the high frequencies, the (false)
a. collector voltage must be largeb. collector current must be highc. base should be thind. emitter area must be large
18. For microwave transistor to operate at the high frequencies, the (false)
a. collector voltage must be largeb. collector current must be highc. base should be thind. emitter area must be large
19. Varactor diode may be useful at microwave frequencies (false)
a. for electronic tuningb. for frequency multiplicationc. as an oscillatord. as a parametric amplifier
19. Varactor diode may be useful at microwave frequencies (false)
a. for electronic tuningb. for frequency multiplicationc. as an oscillatord. as a parametric amplifier
20. If high order frequency multiplication is required from a diode multiplier,
a. the resistive cuttoff frequency must be high
b. a small value of base resistance is required
c. a step recovery diode must be used
d. a large range of capacitance variation is needed
20. If high order frequency multiplication is required from a diode multiplier,
a. the resistive cuttoff frequency must be high
b. a small value of base resistance is required
c. a step recovery diode must be used
d. a large range of capacitance variation is needed
21. Parametric amplifier has an input and output frequency of 2.25GHz and is pumped at 4.5GHz. It is a
a. traveling wave amplifierb. degenerative amplifierc. lower sideband up converterd. upper sideband up converter
21. Parametric amplifier has an input and output frequency of 2.25GHz and is pumped at 4.5GHz. It is a
a. traveling wave amplifierb. degenerative amplifierc. lower sideband up converterd. upper sideband up converter
22. Non degenerate parametric amplifier has an input frequency Fi and a pump frequency Fp. The idler frequency is
a. Fib. 2Fic. Fi – Fpd. Fp – Fi
22. Non degenerate parametric amplifier has an input frequency Fi and a pump frequency Fp. The idler frequency is
a. Fib. 2Fic. Fi – Fpd. Fp – Fi
23. Traveling wave parametric amplifiers are used to
a. provide a greater gainb. reduce the number of varactor
diodes requiredc. avoid the need for coolingd. provide a greater bandwidth
23. Traveling wave parametric amplifiers are used to
a. provide a greater gainb. reduce the number of varactor
diodes requiredc. avoid the need for coolingd. provide a greater bandwidth
24. A parametric amplifier sometimes uses a circulator to
a. prevent noise feedbackb. allow the antenna to be used
simultaneously for transmission and reception
c. separate the signal and idler frequencies
d. permit more efficient pumping
24. A parametric amplifier sometimes uses a circulator to
a. prevent noise feedbackb. allow the antenna to be used
simultaneously for transmission and reception
c. separate the signal and idler frequencies
d. permit more efficient pumping
25. The non degenerate one port parametric amplifier should have a high ratio of pump to signal frequency because this
a. permits satisfactory high frequency operation
b. yields a low noise figurec. reduces the pump power
requiredd. permits satisfactory low
frequency operation
25. The non degenerate one port parametric amplifier should have a high ratio of pump to signal frequency because this
a. permits satisfactory high frequency operation
b. yields a low noise figurec. reduces the pump power
requiredd. permits satisfactory low
frequency operation
26. Tunnel diodea. has a tiny hole through its center
to facilitate tunnelingb. is a point contact diode with a
very high reverse resistancec. uses a high doping level to
provide a narrow junctiond. works by quantum tunneling
exhibited by gallium arsenide only
26. Tunnel diodea. has a tiny hole through its center
to facilitate tunnelingb. is a point contact diode with a
very high reverse resistancec. uses a high doping level to
provide a narrow junctiond. works by quantum tunneling
exhibited by gallium arsenide only
27. A tunnel diode is loosely coupled to its cavity in order to
a. increase the frequency stabilityb. increase the availability negative
resistancec. facilitate tunningd. allow operation at the highest
frequencies
27. A tunnel diode is loosely coupled to its cavity in order to
a. increase the frequency stabilityb. increase the availability negative
resistancec. facilitate tunningd. allow operation at the highest
frequencies
28. The negative resistance in a tunnel diode
a. is maximum at the peak point of the characteristic
b. is available between the peak and valley points
c. is maximum at the valley pointd. may be improved by the use of
reverse bias
28. The negative resistance in a tunnel diode
a. is maximum at the peak point of the characteristic
b. is available between the peak and valley points
c. is maximum at the valley pointd. may be improved by the use of
reverse bias
29. The biggest advantage of gallium antimonide over germanium for tunnel diode use is that the former has a
a. lower noiseb. higher ion mobilityc. larger voltage swingd. simpler fabrication process
29. The biggest advantage of gallium antimonide over germanium for tunnel diode use is that the former has a
a. lower noiseb. higher ion mobilityc. larger voltage swingd. simpler fabrication process
30. Negative resistance is obtained with a Gunn diode because of
a. electron transfer to less mobile energy level
b. avalanche breakdown with the high voltage current
c. tunneling across the junctiond. electron domains forming at the
junction
30. Negative resistance is obtained with a Gunn diode because of
a. electron transfer to less mobile energy level
b. avalanche breakdown with the high voltage current
c. tunneling across the junctiond. electron domains forming at the
junction
31. For Gunn diodes, gallium arsenide is preferred to silicon because the former
a. has suitable empty energy band, which silicon does not have
b. has a higher ion mobilityc. has lower noise at the highest
frequenciesd. is capable of handling higher
power densities
31. For Gunn diodes, gallium arsenide is preferred to silicon because the former
a. has suitable empty energy band, which silicon does not have
b. has a higher ion mobilityc. has lower noise at the highest
frequenciesd. is capable of handling higher
power densities
32. The biggest disadvantage of IMPATT diode is its
a. lower efficiency than that of the other microwave diodes
b. high noisec. inability to provide pulsed
operationd. lower ability handling ability
32. The biggest disadvantage of IMPATT diode is its
a. lower efficiency than that of the other microwave diodes
b. high noisec. inability to provide pulsed
operationd. lower ability handling ability
33. The magnetic field is used with a ruby maser to
a. provide sharp focusing for the electron beam
b. increase the population inversionc. allow room temperature
operationd. provide frequency adjustments
33. The magnetic field is used with a ruby maser to
a. provide sharp focusing for the electron beam
b. increase the population inversionc. allow room temperature
operationd. provide frequency adjustments
34. The ruby maser has been preferred to the ammonia maser for microwave amplification, because the former has
a. a much greater bandwidthb. a better frequency stabilityc. a low noise figured. no need for circulator
34. The ruby maser has been preferred to the ammonia maser for microwave amplification, because the former has
a. a much greater bandwidthb. a better frequency stabilityc. a low noise figured. no need for circulator
35. Parametric amplifiers and masers are similar to each other in that both (false)
a. must have pumpingb. are extremely low noise
amplifiersc. must be cooled down to a few
Kelvind. generally require circulators,
since they are one port devices
35. Parametric amplifiers and masers are similar to each other in that both (false)
a. must have pumpingb. are extremely low noise
amplifiersc. must be cooled down to a few
Kelvind. generally require circulators,
since they are one port devices
36. Maser RF amplifier is not really suitable for
a. radio astronomyb. satellite communicationsc. radard. troposcatter receivers
36. Maser RF amplifier is not really suitable for
a. radio astronomyb. satellite communicationsc. radard. troposcatter receivers
37. The ruby maser laser differs from the ruby maser in that the former
a. does not require pumpingb. needs no resonatorc. is an oscillatord. produces much lower powers
37. The ruby maser laser differs from the ruby maser in that the former
a. does not require pumpingb. needs no resonatorc. is an oscillatord. produces much lower powers
38. The output from a laser is monochromatic; this means that it is
a. infraredb. polarizedc. narrow beamd. single frequency
38. The output from a laser is monochromatic; this means that it is
a. infraredb. polarizedc. narrow beamd. single frequency
39. For a given average power, the peak output power of a ruby laser may be increased by
a. using coolingb. using Q spoilingc. increasing the magnetic fieldd. dispensing the Farby-Perot
resonator
39. For a given average power, the peak output power of a ruby laser may be increased by
a. using coolingb. using Q spoilingc. increasing the magnetic fieldd. dispensing the Farby-Perot
resonator
40. Communications laser are used with optical fiber, rather that in open links, to
a. ensure that the beams does not spread
b. prevent atmospheric interference
c. prevent interference by other lasers
d. ensure that people are not blinded by them
40. Communications laser are used with optical fiber, rather that in open links, to
a. ensure that the beams does not spread
b. prevent atmospheric interference
c. prevent interference by other lasers
d. ensure that people are not blinded by them
41. Indicate the false statement. The advantage of semiconductor lasers over LEDs include
a. monochromatic outputb. higher power outputc. lower costd. ability to be pulsed at higher
rates
41. Indicate the false statement. The advantage of semiconductor lasers over LEDs include
a. monochromatic outputb. higher power outputc. lower costd. ability to be pulsed at higher
rates
CHAPTER 13: PULSE COMMUNICATIONS
1. Indicate which of the following is not a binary code
a. morseb. baudotc. CCITT-2d. ARQ
1. Indicate which of the following is not a binary code
a. morseb. baudotc. CCITT-2d. ARQ
2. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is
a. 2b. Log1016c. 8d. 4
2. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is
a. 2b. Log1016c. 8d. 4
3. A signaling system in which each letter alphabet is represented by a different symbol is not because
a. it would be too difficult for an operator to memorize
b. it is redundantc. noise would introduce too many
errorsd. too many pulses per letter are
required
3. A signaling system in which each letter alphabet is represented by a different symbol is not because
a. it would be too difficult for an operator to memorize
b. it is redundantc. noise would introduce too many
errorsd. too many pulses per letter are
required
4. The Hartley law states thata. the maximum rate of information
transmission depends on the channel bandwidth
b. the maximum rate of information transmission depends on depth of modulation
c. redundancy is essentiald. only binary codes may be used
4. The Hartley law states thata. the maximum rate of information
transmission depends on the channel bandwidth
b. the maximum rate of information transmission depends on depth of modulation
c. redundancy is essentiald. only binary codes may be used
5. Indicate the false statement. In order to combat noise,
a. the channel bandwidth may be increased
b. redundancy may be usedc. the transmitted power may be
increasedd. the signalling rate may be
reduced
5. Indicate the false statement. In order to combat noise,
a. the channel bandwidth may be increased
b. redundancy may be usedc. the transmitted power may be
increasedd. the signalling rate may be
reduced
6. The most common modulation system used for telegraphy is
a. frequency shift keyingb. two tone modulationc. pulse code modulationd. single tone modulation
6. The most common modulation system used for telegraphy is
a. frequency shift keyingb. two tone modulationc. pulse code modulationd. single tone modulation
7. Pulse width modulation may be generated
a. by differentiating pulse position modulation
b. with a mono stable multivibratorc. by integrating the signald. with free running multi vibrator
7. Pulse width modulation may be generated
a. by differentiating pulse position modulation
b. with a mono stable multivibratorc. by integrating the signald. with free running multi vibrator
8. Indicate which of the following system is digital
a. Pulse position modulationb. Pulse code modulationc. Pulse width modulationd. Pulse frequency modulation
8. Indicate which of the following system is digital
a. Pulse position modulationb. Pulse code modulationc. Pulse width modulationd. Pulse frequency modulation
9. Quantizing noise occurs ina. time division multiplexb. frequency division multiplexc. pulse code modulationd. pulse width modulation
9. Quantizing noise occurs ina. time division multiplexb. frequency division multiplexc. pulse code modulationd. pulse width modulation
10. The modulation system inherently most noise resistant is
a. SSB, suppressed carrierb. Frequency modulationc. Pulse position modulationd. Pulse code modulation
10. The modulation system inherently most noise resistant is
a. SSB, suppressed carrierb. Frequency modulationc. Pulse position modulationd. Pulse code modulation
11. In order to reduce quantizing noise, one must
a. increase the number of standard amplitudes
b. sends pulses whose sides are most nearly vertical
c. use an RF amplifier in the receiver
d. increase the number of samples per second
11. In order to reduce quantizing noise, one must
a. increase the number of standard amplitudes
b. sends pulses whose sides are most nearly vertical
c. use an RF amplifier in the receiver
d. increase the number of samples per second
12. The Hartley Shannon theorems sets a limit on the
a. highest frequency that may be sent over a given channel
b. maximum capacity of a channel with a given noise level
c. maximum number of coding levels in a channel with a given noise level
d. maximum number of quantizing levels in a channel of a given bandwidth
12. The Hartley Shannon theorems sets a limit on the
a. highest frequency that may be sent over a given channel
b. maximum capacity of a channel with a given noise level
c. maximum number of coding levels in a channel with a given noise level
d. maximum number of quantizing levels in a channel of a given bandwidth
13. Indicate which of the following pulse modulation system analog.
a. PCMb. Differential PCMc. PWMd. Delta
13. Indicate which of the following pulse modulation system analog.
a. PCMb. Differential PCMc. PWMd. Delta
14. Companding is useda. to overcome quantizing noise in
PCMb. in PCM transmitter, to allow
amplitude limiting in the receiversc. to protect small signals in PCM
from quantizing distortiond. in the PCM receivers to
overcome impulse noise
14. Companding is useda. to overcome quantizing noise in
PCMb. in PCM transmitter, to allow
amplitude limiting in the receiversc. to protect small signals in PCM
from quantizing distortiond. in the PCM receivers to
overcome impulse noise
15. The biggest disadvantage of PCM is
a. its inability to handle analog signals
b. the high error rate which its quantizing noise introduces
c. its incompatibility with TDMd. the large bandwidths that are
required for it
15. The biggest disadvantage of PCM is
a. its inability to handle analog signals
b. the high error rate which its quantizing noise introduces
c. its incompatibility with TDMd. the large bandwidths that are
required for it
CHAPTER 14: DIGITAL COMMUNICATIONS
1. Digital signalsa. do not provide a continuous set
of valuesb. present values as discrete stepsc. can utilized decimal or binary
systemsd. all of the above
1. Digital signalsa. do not provide a continuous set
of valuesb. present values as discrete stepsc. can utilized decimal or binary
systemsd. all of the above
2. The event which marked the start of the modern computer age was
a. design of the ENIAC computerb. development of the Hollerith
codec. development of the transistord. development of the disk drives
for data storage
2. The event which marked the start of the modern computer age was
a. design of the ENIAC computerb. development of the Hollerith
codec. development of the transistord. development of the disk drives
for data storage
3. The baud ratea. is always equal to the bit transfer
rateb. is equal to twice the bandwidth
of an ideal channelc. is not equal to the signaling rated. is equal to one half the
bandwidth of an ideal channel
3. The baud ratea. is always equal to the bit transfer
rateb. is equal to twice the bandwidth
of an ideal channelc. is not equal to the signaling rated. is equal to one half the
bandwidth of an ideal channel
4. The Shannon Hartley Lawa. refers to distortionb. defines bandwidthc. describes signalling ratesd. refers to noise
4. The Shannon Hartley Lawa. refers to distortionb. defines bandwidthc. describes signalling ratesd. refers to noise
5. The code which provides parity check is
a. Baudotb. ASCIIc. EBCDICd. CCITT-2
5. The code which provides parity check is
a. Baudotb. ASCIIc. EBCDICd. CCITT-2
6. Forward error correcting code corrects errors by
a. requiring partial retransmission of the signal
b. requiring retransmission of the entire signal
c. requiring no part of the signal to be retransmitted
d. using parity to correct the errors in all cases
6. Forward error correcting code corrects errors by
a. requiring partial retransmission of the signal
b. requiring retransmission of the entire signal
c. requiring no part of the signal to be retransmitted
d. using parity to correct the errors in all cases
7. Full duplex operationa. requires two pairs of cablesb. can transfer data in both
directions at oncec. requires modems at both ends of
the circuitd. all of the above
7. Full duplex operationa. requires two pairs of cablesb. can transfer data in both
directions at oncec. requires modems at both ends of
the circuitd. all of the above
8. The RS-232 interfacea. interconnects data sets and
transmission circuitsb. uses several different connectorsc. permits custom wiring of signal
lines to the connector pins as desired
d. all of the above
8. The RS-232 interfacea. interconnects data sets and
transmission circuitsb. uses several different connectorsc. permits custom wiring of signal
lines to the connector pins as desired
d. all of the above
9. Switching systemsa. improve the efficiency of the
data transferb. are not used in data systemc. require additional linesd. are limited to small data
networks
9. Switching systemsa. improve the efficiency of the
data transferb. are not used in data systemc. require additional linesd. are limited to small data
networks
10. The data transmission rate of a modem is measured in
a. Bytes per secondb. Baud ratec. Bits per secondd. Megahertz
10. The data transmission rate of a modem is measured in
a. Bytes per secondb. Baud ratec. Bits per secondd. Megahertz
CHAPTER 15: BROADBAND COMMUNICATIONS SYSTEM
1. Broadband long distance communications are originally made possible by the advent of
a. telegraph cablesb. repeater amplifiersc. HF radiod. Geostationary satellites
1. Broadband long distance communications are originally made possible by the advent of
a. telegraph cablesb. repeater amplifiersc. HF radiod. Geostationary satellites
2. Scheme in which several channels are interleaved and then transmitted together is known as
a. Frequency division multiplexb. Time division multiplexc. A groupd. A super group
2. Scheme in which several channels are interleaved and then transmitted together is known as
a. Frequency division multiplexb. Time division multiplexc. A groupd. A super group
3. Basic group Ba. occupies the frequency range
from 60 to 108 KHzb. consist of erect channels onlyc. is formed at the group
translating equipmentd. consist of five super group
3. Basic group Ba. occupies the frequency range
from 60 to 108 KHzb. consist of erect channels onlyc. is formed at the group
translating equipmentd. consist of five super group
4. Time division multiplexa. can be used with PCM onlyb. combines five groups into a
super groupc. stacks 24 channels in adjacent
frequency slotsd. interleaves pulses belonging to
different transmissions
4. Time division multiplexa. can be used with PCM onlyb. combines five groups into a
super groupc. stacks 24 channels in adjacent
frequency slotsd. interleaves pulses belonging to
different transmissions
5. The number of repeaters along a coaxial cable link depends on
a. whether separate tubes are used for the two directions of transmission
b. the bandwidth of the systemc. the number of coaxial cables in
the tubed. the separation of the equalizers
5. The number of repeaters along a coaxial cable link depends on
a. whether separate tubes are used for the two directions of transmission
b. the bandwidth of the systemc. the number of coaxial cables in
the tubed. the separation of the equalizers
6. Super group pilot isa. applied at each multiplexing bayb. used to regulate the gain of
individual repeatersc. applied at each adjustable
equalizerd. fed in at a GTE
6. Super group pilot isa. applied at each multiplexing bayb. used to regulate the gain of
individual repeatersc. applied at each adjustable
equalizerd. fed in at a GTE
7. Microwave link repeaters are typically 50km apart
a. because of atmospheric attenuation
b. because of output power limitations
c. because of earths curvatured. to ensure that the applied dc
voltage is not excessive
7. Microwave link repeaters are typically 50km apart
a. because of atmospheric attenuation
b. because of output power limitations
c. because of earths curvatured. to ensure that the applied dc
voltage is not excessive
8. Microwave links are generally preferred to coaxial cable for television transmission because
a. they have less overall phase distortion
b. they are cheaperc. of their greater bandwidthsd. of their relatively immunity to
impulse noise
8. Microwave links are generally preferred to coaxial cable for television transmission because
a. they have less overall phase distortion
b. they are cheaperc. of their greater bandwidthsd. of their relatively immunity to
impulse noise
9. Armored submarine cable is useda. to protect the cable at great
depthsb. to prevent inadvertent ploughing
in of the cablec. for the shallow shore ends of the
cabled. to prevent insulation breakdown
from the high feeds voltages
9. Armored submarine cable is useda. to protect the cable at great
depthsb. to prevent inadvertent ploughing
in of the cablec. for the shallow shore ends of the
cabled. to prevent insulation breakdown
from the high feeds voltages
10. Submarine cable repeater contains among other equipments
a. a dc power supply and regulatorb. filters for two directions of
transmissionc. multiplexing and demultiplexing
equipmentd. pilot inject and pilot extract
equipment
10. Submarine cable repeater contains among other equipments
a. a dc power supply and regulatorb. filters for two directions of
transmissionc. multiplexing and demultiplexing
equipmentd. pilot inject and pilot extract
equipment
11. Geostationary satellitea. is motionless in space (except for
its spins)b. is not really stationary at all but
its orbits the earth within a 24hr period
c. appears stationary above the Earth’s magnetic poles
d. is located at height of 35,800km to ensure global coverage
11. Geostationary satellitea. is motionless in space (except for
its spins)b. is not really stationary at all but
its orbits the earth within a 24hr period
c. appears stationary above the Earth’s magnetic poles
d. is located at height of 35,800km to ensure global coverage
12. Indicate the correct statement regarding satellite communications.
a. if two earth stations do not face a common satellite they should be communicate via double satellite hop
b. satellite are allocated so that it is impossible for two earth station not to face the same satellite
c. collocated earth station are used for frequency diversity
d. a satellite earth station must have as many receiver chains as there are carriers transmitted to it.
12. Indicate the correct statement regarding satellite communications.
a. if two earth stations do not face a common satellite they should be communicate via double satellite hop
b. satellite are allocated so that it is impossible for two earth station not to face the same satellite
c. collocated earth station are used for frequency diversity
d. a satellite earth station must have as many receiver chains as there are carriers transmitted to it.
13. Satellite used for inter continental communications are known as
a. Comsatb. Domsatc. Marisatd. Intelsat
13. Satellite used for inter continental communications are known as
a. Comsatb. Domsatc. Marisatd. Intelsat
14. Identical telephone number in different parts of a country are distinguished by their
a. language digitsb. access digitsc. area codesd. central office codes
14. Identical telephone number in different parts of a country are distinguished by their
a. language digitsb. access digitsc. area codesd. central office codes
15. Telephone traffic is measureda. with echo cancellersb. by their relative congestionsc. in terms of the grade of servicesd. in erlangs
15. Telephone traffic is measureda. with echo cancellersb. by their relative congestionsc. in terms of the grade of servicesd. in erlangs
16. In order to separate channels in a TDM receiver, it is necessary to use
a. AND gatesb. Bandpass filterc. Differentiationd. Integration
16. In order to separate channels in a TDM receiver, it is necessary to use
a. AND gatesb. Bandpass filterc. Differentiationd. Integration
17. To separate channels in a FDM receiver, it is necessary to use
a. AND gatesb. Bandpass filterc. Differentiationd. Integration
17. To separate channels in a FDM receiver, it is necessary to use
a. AND gatesb. Bandpass filterc. Differentiationd. Integration
18. Higher order TDM levels are obtained by
a. dividing pulse widthsb. using the a-lawc. using the u-lawd. forming supermastergroups
18. Higher order TDM levels are obtained by
a. dividing pulse widthsb. using the a-lawc. using the u-lawd. forming supermastergroups
19. Losses in optical fiber can be caused by (false)
a. impuritiesb. microbendingc. attenuation in the glassd. stepped index operation
19. Losses in optical fiber can be caused by (false)
a. impuritiesb. microbendingc. attenuation in the glassd. stepped index operation
20. The 1.55um “window” is not yet in used with fiber optic system because
a. the attenuation is higher than at 0.85um
b. the attenuation is higher than at 1.3um
c. suitable laser devices have not yet been developed
d. it does not lend itself to wavelength multiplexing
20. The 1.55um “window” is not yet in used with fiber optic system because
a. the attenuation is higher than at 0.85um
b. the attenuation is higher than at 1.3um
c. suitable laser devices have not yet been developed
d. it does not lend itself to wavelength multiplexing
21. Indicate which of the following is not a submarine cable
a. TAT-7b. INTELSAT Vc. ATLANTISd. CANTAT 2
21. Indicate which of the following is not a submarine cable
a. TAT-7b. INTELSAT Vc. ATLANTISd. CANTAT 2
22. Indicate which of the following is an American Domsat system
a. INTELSATb. COMSATc. TELSATd. INMARSAT
22. Indicate which of the following is an American Domsat system
a. INTELSATb. COMSATc. TELSATd. INMARSAT
CHAPTER 16: RADAR SYSTEM
1. If the peak transmitted power in a radar system is increased by factor of 16, the maximum range will be increased by factor of
a. 2b. 4c. 8d. 16
1. If the peak transmitted power in a radar system is increased by factor of 16, the maximum range will be increased by factor of
a. 2b. 4c. 8d. 16
2. If the antenna diameter in a radar system is increased by factor of 4, the maximum range will be increased by factor of
a. (2)^1/2b. 2c. 4d. 8
2. If the antenna diameter in a radar system is increased by factor of 4, the maximum range will be increased by factor of
a. (2)^1/2b. 2c. 4d. 8
3. If the ratio of the antenna diameter to the wavelength in a radar system is high this will result in (false)
a. large maximum rangeb. good target discriminationc. difficult target acquisitiond. increased capture area
3. If the ratio of the antenna diameter to the wavelength in a radar system is high this will result in (false)
a. large maximum rangeb. good target discriminationc. difficult target acquisitiond. increased capture area
4. The radar cross section to a target (false)
a. depends on the frequency usedb. may be reduced by special
coating of the targetc. depends on the aspect of a
target, if this is nonsphericald. is equal to the actual cross
sectional area for small targets
4. The radar cross section to a target (false)
a. depends on the frequency usedb. may be reduced by special
coating of the targetc. depends on the aspect of a
target, if this is nonsphericald. is equal to the actual cross
sectional area for small targets
5. Flat topped rectangular pulses must be transmitted in radar to (false)
a. allow good minimum rangeb. make the returned echoes easier
to distinguish from noisec. prevent frequency changes in
the magnetrond. allow accurate range
measurements
5. Flat topped rectangular pulses must be transmitted in radar to (false)
a. allow good minimum rangeb. make the returned echoes easier
to distinguish from noisec. prevent frequency changes in
the magnetrond. allow accurate range
measurements
6. High PRF will (false)a. make the returned echoes easier
to distinguish from noiseb. make target tracing easier with
conical scanningc. increase maximum ranged. have no effect on the range
resolution
6. High PRF will (false)a. make the returned echoes easier
to distinguish from noiseb. make target tracing easier with
conical scanningc. increase maximum ranged. have no effect on the range
resolution
7. The IF bandwidth of a radar receiver is inversely proportional to the
a. pulse widthb. pulse repetition frequencyc. pulse intervald. square root of the peak
transmitted power
7. The IF bandwidth of a radar receiver is inversely proportional to the
a. pulse widthb. pulse repetition frequencyc. pulse intervald. square root of the peak
transmitted power
8. If a return echo arrives after the allocated pulse interval,
a. it will interfere with the operation of the transmitter
b. the receiver might be overloadedc. it will not be receivedd. the target will appear closer than
it really is
8. If a return echo arrives after the allocated pulse interval,
a. it will interfere with the operation of the transmitter
b. the receiver might be overloadedc. it will not be receivedd. the target will appear closer than
it really is
9. After a target has been acquired, the best scanning system for tracking is
a. noddingb. spiralc. conicald. helical
9. After a target has been acquired, the best scanning system for tracking is
a. noddingb. spiralc. conicald. helical
10. If the target cross section is changing, the best system for accurate tracking is
a. lobe switchingb. sequential lobbingc. conical scanningd. mono pulse
10. If the target cross section is changing, the best system for accurate tracking is
a. lobe switchingb. sequential lobbingc. conical scanningd. mono pulse
11. The biggest disadvantage of CW Doppler radar is that
a. it does not give the target velocity
b. it does not give the target rangec. a transponder is required at the
targetd. it does not give the target
position
11. The biggest disadvantage of CW Doppler radar is that
a. it does not give the target velocity
b. it does not give the target rangec. a transponder is required at the
targetd. it does not give the target
position
12. A scope displaysa. the target position and rangeb. the target range, but not positionc. the target position, but not the
ranged. neither range nor position, but
only velocity
12. A scope displaysa. the target position and rangeb. the target range, but not positionc. the target position, but not the
ranged. neither range nor position, but
only velocity
13. The Doppler effect is used in (false)
a. moving target plotting on the PPIb. the MTI systemc. FM radard. CW radar
13. The Doppler effect is used in (false)
a. moving target plotting on the PPIb. the MTI systemc. FM radard. CW radar
14. The coho in MTI radar operates at the
a. intermediate frequencyb. transmitted frequencyc. received frequencyd. pulse repetition frequency
14. The coho in MTI radar operates at the
a. intermediate frequencyb. transmitted frequencyc. received frequencyd. pulse repetition frequency
15. The function of the quartz delay line in an MTI radar is to
a. help subtracting a complete scan from the previous scan
b. match the phase of the coho and the stalo
c. match the phase of the coho and the output oscillator
d. delay a sweep so that the next sweep can be subtracted from it
15. The function of the quartz delay line in an MTI radar is to
a. help subtracting a complete scan from the previous scan
b. match the phase of the coho and the stalo
c. match the phase of the coho and the output oscillator
d. delay a sweep so that the next sweep can be subtracted from it
16. A solution to the “blind speed” problem is to
a. change the Doppler frequencyb. Vary the PRFc. Use monopulsed. Use MTI
16. A solution to the “blind speed” problem is to
a. change the Doppler frequencyb. Vary the PRFc. Use monopulsed. Use MTI
17. Indicate which one of the following applications are advantages of radar beacons is false:
a. target identificationb. navigationc. very significant extension of the
maximum ranged. more accurate tracking of enemy
targets
17. Indicate which one of the following applications are advantages of radar beacons is false:
a. target identificationb. navigationc. very significant extension of the
maximum ranged. more accurate tracking of enemy
targets
18. Compared with other types of radar, phased array radar has the following advantages (false)
a. very fast scanningb. ability to tract and scan
simultaneouslyc. circuit simplicityd. ability to track may targets
simultaneously
18. Compared with other types of radar, phased array radar has the following advantages (false)
a. very fast scanningb. ability to tract and scan
simultaneouslyc. circuit simplicityd. ability to track may targets
simultaneously
CHAPTER 17: TELEVISION FUNDAMENTALS
1. The number of lines per field in the United State TV system is
a. 262 ½b. 525c. 30d. 60
1. The number of lines per field in the United State TV system is
a. 262 ½b. 525c. 30d. 60
2. The number of frames per second in the US TV system is
a. 60b. 262 ½c. 4.5d. 30
2. The number of frames per second in the US TV system is
a. 60b. 262 ½c. 4.5d. 30
3. The number of lines per second in the US TV system is
a. 31500b. 15750c. 262 ½d. 525
3. The number of lines per second in the US TV system is
a. 31500b. 15750c. 262 ½d. 525
4. The channel width in the US TV system, in MHz is
a. 41.25b. 6c. 4.5d. 3.58
4. The channel width in the US TV system, in MHz is
a. 41.25b. 6c. 4.5d. 3.58
5. Interlacing is used in television to
a. produce the illusion of motionb. ensure that all the lines on the
screen are scanned, not merely the alternate ones
c. simplify the vertical sync pulse train
d. avoid flicker
5. Interlacing is used in television to
a. produce the illusion of motionb. ensure that all the lines on the
screen are scanned, not merely the alternate ones
c. simplify the vertical sync pulse train
d. avoid flicker
6. The signals sent by the TV transmitter to ensure correct scanning in the receiver are called
a. syncb. chromac. luminanced. video
6. The signals sent by the TV transmitter to ensure correct scanning in the receiver are called
a. syncb. chromac. luminanced. video
7. In the US color television system, the intercarrier frequency, in MHz
a. 3.58b. 3.579545c. 4.5d. 45.75
7. In the US color television system, the intercarrier frequency, in MHz
a. 3.58b. 3.579545c. 4.5d. 45.75
8. Indicate which voltages are not found in the output of a normal monochrome receiver video detector
a. syncb. videoc. sweepd. sound
8. Indicate which voltages are not found in the output of a normal monochrome receiver video detector
a. syncb. videoc. sweepd. sound
9. The carrier transmitted 1.25MHz above the bottom frequency in a US TV system channel is the
a. sound carrierb. chroma carrierc. intercarrierd. picture carrier
9. The carrier transmitted 1.25MHz above the bottom frequency in a US TV system channel is the
a. sound carrierb. chroma carrierc. intercarrierd. picture carrier
10. In television 4:3 represents thea. interlace ratiob. maximum horizontal deflectionc. aspect ratiod. ratio of the two diagonals
10. In television 4:3 represents thea. interlace ratiob. maximum horizontal deflectionc. aspect ratiod. ratio of the two diagonals
11. Equalizing pulses in TV are sent during
a. horizontal blankingb. vertical blankingc. the serrationsd. the horizontal retrace
11. Equalizing pulses in TV are sent during
a. horizontal blankingb. vertical blankingc. the serrationsd. the horizontal retrace
12. An odd number of lines per frame forms part of every one of the world’s TV system. This is
a. done to assist interlaceb. purely an accidentc. to ensure that line and frame
frequencies can be obtained from the same original source
d. done to minimize interference with the chroma subcarriers
12. An odd number of lines per frame forms part of every one of the world’s TV system. This is
a. done to assist interlaceb. purely an accidentc. to ensure that line and frame
frequencies can be obtained from the same original source
d. done to minimize interference with the chroma subcarriers
13. The function of the serrations in the composite video waveform is to
a. equalized the charge in the integrator before the start of vertical retrace
b. help vertical synchronizationc. help horizontal synchronizationd. simplify the generation of
vertical sync pulse
13. The function of the serrations in the composite video waveform is to
a. equalized the charge in the integrator before the start of vertical retrace
b. help vertical synchronizationc. help horizontal synchronizationd. simplify the generation of
vertical sync pulse
14. The width of the vertical pulse in US TV system is
a. 21Hb. 3Hc. Hd. 0.5H
14. The width of the vertical pulse in US TV system is
a. 21Hb. 3Hc. Hd. 0.5H
15. Indicate which of the following frequencies will not be found in the output of a normal TV receiver tuner:
a. 4.5 MHzb. 41.25 MHzc. 45.75 MHzd. 42.17 MHz
15. Indicate which of the following frequencies will not be found in the output of a normal TV receiver tuner:
a. 4.5 MHzb. 41.25 MHzc. 45.75 MHzd. 42.17 MHz
16. The video voltage applied to the picture tube of a television receiver is fed in
a. between grid and groundb. to the yokec. to the anoded. between the grid and cathode
16. The video voltage applied to the picture tube of a television receiver is fed in
a. between grid and groundb. to the yokec. to the anoded. between the grid and cathode
17. The circuit that separates the sync pulse from the composite video waveform is
a. the keyed AGC amplifierb. a clipperc. an integratord. a differentiator
17. The circuit that separates the sync pulse from the composite video waveform is
a. the keyed AGC amplifierb. a clipperc. an integratord. a differentiator
18. The output of the vertical amplifier, applied to the yoke in the TV receiver, consist of
a. direct currentb. amplified vertical sync pulsesc. saw tooth voltaged. a saw tooth current
18. The output of the vertical amplifier, applied to the yoke in the TV receiver, consist of
a. direct currentb. amplified vertical sync pulsesc. saw tooth voltaged. a saw tooth current
19. The HV anode supply for the picture tube for a TV receiver is generated in the
a. main transformerb. vertical output stagec. horizontal output staged. horizontal deflection stage
19. The HV anode supply for the picture tube for a TV receiver is generated in the
a. main transformerb. vertical output stagec. horizontal output staged. horizontal deflection stage
20. Another name for the horizontal retrace in a TV receiver is the
a. ringinb. burstc. damperd. flyback
20. Another name for the horizontal retrace in a TV receiver is the
a. ringinb. burstc. damperd. flyback
21. Indicate which of the following signal is not transmitted in color TV:
a. Yb. Qc. Rd. I
21. Indicate which of the following signal is not transmitted in color TV:
a. Yb. Qc. Rd. I
22. The Shadow mask in a color picture tube is used to
a. reduce x-ray emissionb. ensure that each beam hits only
its own dotsc. increase screen brightnessd. provide degaussing for the
screen
22. The Shadow mask in a color picture tube is used to
a. reduce x-ray emissionb. ensure that each beam hits only
its own dotsc. increase screen brightnessd. provide degaussing for the
screen
23. In a TV receiver the color killera. cuts off the chroma stages
during monochrome receptionb. ensure that no color is
transmitted to monochrome receiver
c. prevents color over loadingd. makes sure that the color burst
is not mistaken for sync pulse, by cutting off reception during the back porch
23. In a TV receiver the color killera. cuts off the chroma stages
during monochrome receptionb. ensure that no color is
transmitted to monochrome receiver
c. prevents color over loadingd. makes sure that the color burst
is not mistaken for sync pulse, by cutting off reception during the back porch
CHAPTER 18: INTRODUCTION TO FIBER OPTIC TECHNOLOGY
1. What is the frequency limit of copper wire?
a. Approximately 0.5 MHzb. Approximately 1.0 MHzc. Approximately 40 GHzd. None of the above
1. What is the frequency limit of copper wire?
a. Approximately 0.5 MHzb. Approximately 1.0 MHzc. Approximately 40 GHzd. None of the above
2. Approximately what is the frequency limit of the optical fiber?
a. 20 GHzb. 1 MHzc. 100 MHzd. 40 MHz
2. Approximately what is the frequency limit of the optical fiber?
a. 20 GHz (no given answer)b. 1 MHzc. 100 MHzd. 40 MHz
3. A single fiber can handle as many voice channels as
a. A pair of copper conductorsb. A 1500-pair cablec. A 500-pair cabled. A 1000- pair cable
3. A single fiber can handle as many voice channels as
a. A pair of copper conductorsb. A 1500-pair cablec. A 500-pair cabled. A 1000- pair cable
4. An incident ray can be defined asa. A light ray reflected from a flat
surfaceb. A light ray directed towards a
surfacec. A diffused light rayd. A light ray that happens
periodically
4. An incident ray can be defined asa. A light ray reflected from a flat
surfaceb. A light ray directed towards a
surfacec. A diffused light rayd. A light ray that happens
periodically
5. The term dispersion describes the process of
a. Separating light into its component frequencies
b. Reflecting light from a smooth surface
c. The process by which light is absorbed by an uneven rough surface
d. Light scattering
5. The term dispersion describes the process of
a. Separating light into its component frequencies
b. Reflecting light from a smooth surface
c. The process by which light is absorbed by an uneven rough surface
d. Light scattering
6. Which of the following terms describes the reason that light is refracted at different angles?
a. Photon energy changes with wavelength
b. Light is refracted as a function of surface smoothness
c. The angle is determined partly by a and b
d. The angle is determined by the index of the materials
6. Which of the following terms describes the reason that light is refracted at different angles?
a. Photon energy changes with wavelength
b. Light is refracted as a function of surface smoothness
c. The angle is determined partly by a and b
d. The angle is determined by the index of the materials
7. The term critical angle describesa. The point at which light is refractedb. The point at which light becomes
invisiblec. The point at which light has gone
from the refractive mode to the reflective mode
d. The point at which light has crossed the boundary layers from one index to another
7. The term critical angle describesa. The point at which light is refractedb. The point at which light becomes
invisiblec. The point at which light has gone
from the refractive mode to the reflective mode
d. The point at which light has crossed the boundary layers from one index to another
8. The cladding which surrounds the fiber core
a. Is used to reduce optical interference
b. Is used to protect the fiberc. Acts to help guide the light in the
cored. Ensures that the refractive index
remains constant
8. The cladding which surrounds the fiber core
a. Is used to reduce optical interference
b. Is used to protect the fiberc. Acts to help guide the light in the
cored. Ensures that the refractive index
remains constant
9. The reflective index number isa. A number which compares the
transparency of a material with that of air
b. A number assigned by the manufacturer to the fiber in question
c. A number which determines the core diameter
d. A term for describing core elasticity
9. The reflective index number isa. A number which compares the
transparency of a material with that of air
b. A number assigned by the manufacturer to the fiber in question
c. A number which determines the core diameter
d. A term for describing core elasticity
10. The terms single mode and multimode are best described as
a. The number of fibers placed into a fiber-optic cable
b. The number of voice channels each fiber can support
c. The number of wavelengths each fiber can support
d. The index number
10. The terms single mode and multimode are best described as
a. The number of fibers placed into a fiber-optic cable
b. The number of voice channels each fiber can support
c. The number of wavelengths each fiber can support
d. The index number
11. The higher the index numbera. The higher the speed of lightb. The lower the speed of lightc. Has no effect on the speed of
lightd. The shorter the wavelength
propagation
11. The higher the index numbera. The higher the speed of lightb. The lower the speed of lightc. Has no effect on the speed of
lightd. The shorter the wavelength
propagation
12. The three major groups in the optical system are
a. The components, the data rate, and the response time
b. The source, the link, and the receiver
c. The transmitter, the cable, and the receiver
d. The source, the link, and the detector
12. The three major groups in the optical system are
a. The components, the data rate, and the response time
b. The source, the link, and the receiver
c. The transmitter, the cable, and the receiver
d. The source, the link, and the detector
13. As light is coupled in a multipoint reflective device, the power is reduce by
a. 1.5 dBb. 0.1 dBc. 0.5 dBd. 0.001 dB
13. As light is coupled in a multipoint reflective device, the power is reduce by
a. 1.5 dBb. 0.1 dBc. 0.5 dBd. 0.001 dB
14. When connector losses, splice losses, and coupler losses are added, what is the final limiting factor?
a. Source powerb. Fiber attenuationc. Connector and splice lossesd. Detector sensitivity
14. When connector losses, splice losses, and coupler losses are added, what is the final limiting factor?
a. Source powerb. Fiber attenuationc. Connector and splice lossesd. Detector sensitivity
15. The term responsivity as it applies to a light detector is best described as
a. The time required for the signal to go from 10 to 90 percent of maximum amplitude
b. The ratio of the diode output current to optical input power
c. The ratio of output current to output power
d. The ratio of output current to input current
15. The term responsivity as it applies to a light detector is best described as
a. The time required for the signal to go from 10 to 90 percent of maximum amplitude
b. The ratio of the diode output current to optical input power
c. The ratio of output current to output power
d. The ratio of output current to input current
16. Loss comparisons between fusion splices and mechanical splices are
a. 1:10b. 10:1c. 20:1d. 1:20
16. Loss comparisons between fusion splices and mechanical splices are
a. 1:10b. 10:1c. 20:1d. 1:20
17. The mechanical splice is best suited for
a. Quicker installation under ideal conditions
b. Minimum attenuation lossesc. Field service conditionsd. Situations in which cost of
equipment is not a factor
17. The mechanical splice is best suited for
a. Quicker installation under ideal conditions
b. Minimum attenuation lossesc. Field service conditionsd. Situations in which cost of
equipment is not a factor
18. EMD is best described by which statement?
a. 70 percent of the core diameter and 70 percent of the fiber NA should be filled with light
b. 70 percent of the fiber diameter and 70 percent of the cone of acceptance should be filled with light
c. 70 percent of input light should be measured at the output
d. 70 percent of the unwanted wavelengths should be attenuated by the fiber
18. EMD is best described by which statement?
a. 70 percent of the core diameter and 70 percent of the fiber NA should be filled with light
b. 70 percent of the fiber diameter and 70 percent of the cone of acceptance should be filled with light
c. 70 percent of input light should be measured at the output
d. 70 percent of the unwanted wavelengths should be attenuated by the fiber
19. Which of the following cables will have the highest launch power capability
a. 50/125/0.2b. 85/125/0.275c. 62.5/125/0.275d. 100/140/0.3
19. Which of the following cables will have the highest launch power capability
a. 50/125/0.2b. 85/125/0.275c. 62.5/125/0.275d. 100/140/0.3
20. The term power budgeting refers toa. The cost of cables, connectors,
equipment, and installationb. The loss of power due to defective
componentsc. The total power available minus the
attenuation lossesd. The comparative costs of fiber and
copper installations
20. The term power budgeting refers toa. The cost of cables, connectors,
equipment, and installationb. The loss of power due to defective
componentsc. The total power available minus the
attenuation lossesd. The comparative costs of fiber and
copper installations
End