kennedy questions.ppt

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