Electronic Systems and TechnologyCompiled by: Aaron Agoot BSECE

CHAPTER 1: INTRODUCTION TO COMMUNICATION SYSTEM

1. In a communication system, noise is most likely to affect the signala. 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 signala. 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 ofa. fundamental and sub harmonic sine wavesb. a fundamental sine wave and an infinite number of harmonicsc. fundamental and harmonic sine waves whose amplitude decreases with the harmonic numberd. 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 ofa. fundamental and sub harmonic sine wavesb. a fundamental sine wave and an infinite number of harmonicsc. fundamental and harmonic sine waves whose amplitude decreases with the harmonic numberd. sinusoidal voltages, some of which are small enough to ignore in practice

3. Indicate the false statement. Modulation is used toa. 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 toa. 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 usuallya. 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 usuallya. unwanted energyb. predictable in characterc. present in the transmitterd. due to any cause

5. Indicate the true statement. Most receivers conforms to thea. amplitude-modulated groupb. frequency-modulated groupc. superheterodyne groupd. tuned radio frequency receiver group

5. Indicate the true statement. Most receivers conforms to thea. 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 longb. an antenna in the standard broadcast AM band is 16,000 ftc. all sound is concentrated from 20 Hz to 20 kHzd. 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 longb. an antenna in the standard broadcast AM band is 16,000 ftc. all sound is concentrated from 20 Hz to 20 kHzd. 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 asa. 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 asa. 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 ofa. superimposing a low frequency on a high frequencyb. superimposing a high frequency on a low frequencyc. carrier interruptiond. frequency shift and phase shift

10. Amplitude modulation is the process ofa. superimposing a low frequency on a high frequencyb. superimposing a high frequency on a low frequencyc. 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 thea. 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 thea. 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 thereforea. halvedb. quadrupledc. doubled. unchanged

3. The value of the resistor creating thermal noise is doubled. The noise power generated is thereforea. halvedb. quadrupledc. doubled. unchanged

4. One of the following is not useful quantity for comparing the noise performance of the receivera. 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 receivera. 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 toa. its resistanceb. its temperaturec. Boltzmanns 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 toa. its resistanceb. its temperaturec. Boltzmanns 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 occursa. 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 occursa. 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 thata. all calculations are based on peak to peak valuesb. calculations are based on peak valuesc. calculations are based on average valuesd. calculations are based on RMS values

9. When dealing with random noise calculations it must be remembered thata. all calculations are based on peak to peak valuesb. calculations are based on peak valuesc. calculations are based on average valuesd. 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 bandwidthb. Flicker is sometimes called demodulation noisec. Noise in mixers is caused by inadequate image frequency rejectiond. 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 bandwidthb. Flicker is sometimes called demodulation noisec. Noise in mixers is caused by inadequate image frequency rejectiond. 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 asa. 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 asa. 4Vb. 3Vc. 2Vd. V

2. In a low-level AM system, amplifiers following the modulated stage must bea. linear devicesb. harmonic devicesc. class C amplifiersd. non linear devices

2. In a low-level AM system, amplifiers following the modulated stage must bea. 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 bea. 50b. 150c. 100d. 66.66

3. If the carrier of a 100 percent modulated AM wave is suppressed, the percentage power saving will bea. 50b. 150c. 100d. 66.66

4. Leak type bias is used in a plate modulated class C amplifier toa. 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 toa. 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 aa. 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 aa. 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 isa. unchangedb. halvedc. doubledd. increase by 50percent

6. The modulation index of an AM is changed from 0 to 1. The transmitted power isa. unchangedb. halvedc. doubledd. increase by 50percent

7. One of the advantages of base modulation over collector modulation of a transistor class C amplifiera. the lower the modulating power requiredb. 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 amplifiera. the lower the modulating power requiredb. 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 indexa. 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 indexa. is 1b. cannot be calculated unless the phase relations are knownc. is 0.5d. is 0.7

9. Amplitude modulation is used for broadcasting becausea. it is more noise immune than other modulation systemb. compared with other system it requires less transmitting powerc. its use avoids receiver complexityd. no other modulation system can provide the necessary bandwidth for high fidelity

9. Amplitude modulation is used for broadcasting becausea. it is more noise immune than other modulation systemb. compared with other system it requires less transmitting powerc. its use avoids receiver complexityd. 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 isa. 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 isa. 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 simplerb. It is possible to generate SSB at any frequencyc. SSB with lower audio frequencies present can be generatedd. 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 simplerb. It is possible to generate SSB at any frequencyc. SSB with lower audio frequencies present can be generatedd. There are more balance modulator, therefore the carrier is suppressed better

4. The most common used filters in SSB generation area. mechanicalb. RCc. LCd. low-pass

4. The most common used filters in SSB generation area. mechanicalb. RCc. LCd. low-pass

5. In an SSB transmitter, one is most likely to find aa. 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 aa. 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 thea. 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 thea. Filter systemb. Phase shift methodc. Third methodd. Balance modulator

8. R3E modulation is sometimes used toa. allow the receiver to have frequency synthesizerb. simplify the frequency stability problem receptionc. reduce the power that must be transmittedd. reduce the bandwidth required for transmission

8. R3E modulation is sometimes used toa. allow the receiver to have frequency synthesizerb. simplify the frequency stability problem receptionc. reduce the power that must be transmittedd. reduce the bandwidth required for transmission

9. To provide two or more voice circuits with the same carrier, it is necessary to usea. ISBb. Carrier reinsertionc. SSB with pilot carrierd. Lincompex

9. To provide two or more voice circuits with the same carrier, it is necessary to usea. ISBb. Carrier reinsertionc. SSB with pilot carrierd. Lincompex

10. Vestigial sideband modulation (C3F) is normally used fora. HF point to point communicationsb. Monoaural broadcastingc. TV broadcastingd. Stereo broadcasting

10. Vestigial sideband modulation (C3F) is normally used fora. HF point to point communicationsb. 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 demodulationb. the higher the discriminator frequency, the better the oscillator frequency stabilityc. the discriminator frequency must not be too low, or the system will faild. 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 demodulationb. the higher the discriminator frequency, the better the oscillator frequency stabilityc. the discriminator frequency must not be too low, or the system will faild. phase modulation is converted into FM by the equalizer circuit

2. In the spectrum of a frequency modulated wavea. the carrier frequency disappears when the modulation index is largeb. the amplitude of any sideband depends on the modulation indexc. the total number of sidebands depend on the modulation indexd. the carrier frequency cannot disappear

2. In the spectrum of a frequency modulated wavea. the carrier frequency disappears when the modulation index is largeb. the amplitude of any sideband depends on the modulation indexc. the total number of sidebands depend on the modulation indexd. the carrier frequency cannot disappear

3. The difference between the phase and frequency modulationa. is purely theoretical because they are the same in practiceb. is too great to make the two system compatiblec. lies in the poorer audio response of the phase modulationd. lies in the different definitions of the modulation index

3. The difference between the phase and frequency modulationa. is purely theoretical because they are the same in practiceb. is too great to make the two system compatiblec. lies in the poorer audio response of the phase modulationd. 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 usedd. 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 usedd. 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 ofa. 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 ofa. mf/3b. mfc. 3mfd. 9mf

6. An FM signal with a deviation () is passed through a mixer, and has its frequency reduced fivefold. The deviation in the output of the mixer isa. 5 b. Indeterminatec. / 5d.

6. An FM signal with a deviation () is passed through a mixer, and has its frequency reduced fivefold. The deviation in the output of the mixer isa. 5 b. Indeterminatec. / 5d.

7. A pre-emphasis circuit provides extra noise immunity bya. 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 bya. 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 amplitudea. 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 amplitudea. 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 isa. 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 isa. 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 providedb. 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 providedb. 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 thea. 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 thea. Reactance FET modulatorb. Varactor diodec. Armstrong modulatord. Reactance bipolar transistor modulator

12. In an FM stereo multiplex transmission, thea. sum signal modulates the 19KHz sub carrierb. difference signal modulates the 19KHz sub carrierc. difference signal modulates the 38KHz sub carrierd. difference signal modulates the 67KHz sub carrier

12. In an FM stereo multiplex transmission, thea. sum signal modulates the 19KHz sub carrierb. difference signal modulates the 19KHz sub carrierc. difference signal modulates the 38KHz sub carrierd. 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 biasb. when the input increases past the threshold of limiting, the gain decreases to keep the output constantc. 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 biasb. when the input increases past the threshold of limiting, the gain decreases to keep the output constantc. the output must be tunedd. leak type biased must be used

3. In a radio receiver with simple AGCa. an increase in signal strength produces more AGCb. the audio stage gain is normally controlled by the AGCc. the faster the AGC time constant, the more accurate the outputd. the highest AGC voltage is produced between stations

3. In a radio receiver with simple AGCa. an increase in signal strength produces more AGCb. the audio stage gain is normally controlled by the AGCc. the faster the AGC time constant, the more accurate the outputd. the highest AGC voltage is produced between stations

4. In broadcast super heterodyne receiver, thea. local oscillator operates below the signal frequencyb. mixer input must be tuned to the signal frequencyc. local oscillator frequency is normally double the IFd. RF amplifier normally works at 455KHz above the carrier frequency

4. In broadcast super heterodyne receiver, thea. local oscillator operates below the signal frequencyb. mixer input must be tuned to the signal frequencyc. local oscillator frequency is normally double the IFd. RF amplifier normally works at 455KHz above the carrier frequency

5. To prevent overloading of the last IF amplifier in the receiver, one should usea. squelchb. variable sensitivityc. variable selectivityd. double conversion

5. To prevent overloading of the last IF amplifier in the receiver, one should usea. 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 isa. 750KHzb. 900KHzc. 1650KHzd. 2100KHz

6. A super heterodyne receiver with an IF of 450KHz is tuned to a signal at 1200KHz. The image frequency isa. 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 discriminatord. 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 discriminatord. the circuit is the same as in a discriminator, except that the diodes are reversed

8. The typical squelch circuit cuts offa. an audio amplifier when the carrier is absentb. RF interference when the signal is weakc. an IF amplifier when the AGC is maximumd. an IF amplifier when the AGC is minimum

8. The typical squelch circuit cuts offa. an audio amplifier when the carrier is absentb. RF interference when the signal is weakc. an IF amplifier when the AGC is maximumd. 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 receivers output during a noise pulse.b. A product demodulator could be used for the reception of morse codec. Double conversion is used to improve image rejectiond. 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 receivers output during a noise pulse.b. A product demodulator could be used for the reception of morse codec. Double conversion is used to improve image rejectiond. Variable sensitivity is used to eliminate selective fading

10. The controlled oscillator synthesizer is sometimes preferred to the direct one becausea. 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 becausea. 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 becausea. 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 toa. reduce the spurious frequency problemb. increase the frequency stability of the synthesizerc. 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 toa. reduce the spurious frequency problemb. increase the frequency stability of the synthesizerc. 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 ofa. improving the effectiveness of the AGCb. reducing the effect of negative peak clippingc. reducing the effect of noise at low modulation depthsd. 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 ofa. improving the effectiveness of the AGCb. reducing the effect of negative peak clippingc. reducing the effect of noise at low modulation depthsd. improving the selectivity of the receiver

14. Indicate the false statement. The super heterodyne receiver replaced the TRF receiver because the latter suffered froma. gain variation over the frequency coverage rangeb. 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 froma. gain variation over the frequency coverage rangeb. insufficient gain and sensitivityc. inadequate selectivity at high frequenciesd. instability

15. The image frequency of a super heterodyne receivera. is created within the receiver itselfb. is due to insufficient adjacent channel rejectionc. is not rejected by the IF tuned circuitsd. is independent of the frequency to which the receiver is tuned

15. The image frequency of a super heterodyne receivera. is created within the receiver itselfb. is due to insufficient adjacent channel rejectionc. is not rejected by the IF tuned circuitsd. 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 toa. 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 toa. 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 poora. blockingb. double spottingc. diversity receptiond. sensitivity

17. A receiver has poor IF selectivity. It will therefore also have poora. blockingb. double spottingc. diversity receptiond. sensitivity

18. Three point tracking is achieved witha. variable selectivityb. the padder capacitorc. double spottingd. double conversion

18. Three point tracking is achieved witha. 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 frequencya. to help the image frequency rejectionb. to permit easier trackingc. because otherwise an intermediate frequency could not be producedd. to allow adequate frequency coverage without switching

19. The local oscillator of a broadcast receiver is tuned to a frequency higher that the incoming frequencya. to help the image frequency rejectionb. to permit easier trackingc. because otherwise an intermediate frequency could not be producedd. 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 goodb. the local oscillator need to be extremely stablec. 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 goodb. the local oscillator need to be extremely stablec. 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 ina. 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 ina. diagonal clippingb. poor AGC operationc. negative-peak clippingd. poor AF response

22. On of the following cannot be used to demodulate SSB.a. product detectorb. diode balance modulatorc. bipolar transistor balance modulatord. complete phase-shift generator

22. On 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. Nothing that no carrier is transmitted with J3E, we see thata. the receiver cannot use a phase comparator for AFCb. adjacent-channel rejection is more difficultc. production of AGC is rather complicated processd. the transmission is not compatible with A3E

23. Indicate the false statement. Nothing that no carrier is transmitted with J3E, we see thata. the receiver cannot use a phase comparator for AFCb. adjacent-channel rejection is more difficultc. production of AGC is rather complicated processd. the transmission is not compatible with A3E

24. When the receiver has good blocking performance, this means thata. it does not suffer from double spottingb. its image frequency rejection is poorc. it is unaffected by AGC derived from nearby transmissiond. its detector suffers from burnout

24. When the receiver has good blocking performance, this means thata. it does not suffer from double spottingb. its image frequency rejection is poorc. it is unaffected by AGC derived from nearby transmissiond. its detector suffers from burnout

25. An AM receiver uses a diode detector to demodulation. This enables it satisfactorily to receivea. single sideband, suppressed carrierb. single sideband, reduced carrierc. ISBd. Single sideband, full carrier

25. An AM receiver uses a diode detector to demodulation. This enables it satisfactorily to receivea. single sideband, suppressed carrierb. 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 ina. 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 ina. 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 connectinga. 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 connectinga. 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 linea. depends on the dielectric constant of the material usedb. increase the velocity along the transmission linec. is governed by the skin effectd. is higher for a solid dielectric than for air

3. The velocity factor of a transmission linea. depends on the dielectric constant of the material usedb. increase the velocity along the transmission linec. is governed by the skin effectd. is higher for a solid dielectric than for air

4. Impedance inversion may be obtained witha. a short circuited stubb. an open circuited stubc. a quarter wave lined. a half wave line

4. Impedance inversion may be obtained witha. 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 area. more difficult to make and connectb. made of transmission line with a different characteristic impedancec. liable to radiated. incapable of giving a full range of reactance

5. Short-circuited stubs are preferred to open circuited stub because the latter area. more difficult to make and connectb. made of transmission line with a different characteristic impedancec. 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 aa. 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 aa. balunb. broadband directional couplerc. double stubd. single stud of adjustable position

7. The main disadvantage of the two hole directional couple isa. low directional couplingb. poor directivityc. high SWRd. narrow bandwidth

7. The main disadvantage of the two hole directional couple isa. low directional couplingb. poor directivityc. high SWRd. narrow bandwidth

8. To couple a coaxial line to a parallel wire, it is best to use aa. slotted lineb. balunc. directional couplerd. quarter wave transformer

8. To couple a coaxial line to a parallel wire, it is best to use aa. slotted lineb. balunc. directional couplerd. quarter wave transformer

9. Indicate the three types of transmission line energy lossesa. (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 lossesa. (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 isa. A device used to connect a transmitter to a directional antennab. A coupling device for matching impedancec. A device used to measure transmission line powerd. An SWR measuring instrument

10. Indicate the true statement below. The directional coupler isa. A device used to connect a transmitter to a directional antennab. A coupling device for matching impedancec. A device used to measure transmission line powerd. 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 becausea. 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 becausea. 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 repeatersa. 20KHzb. 15MHzc. 900MHzd. 12GHz

3. Indicate which of the following frequencies cannot be used for reliable beyond the horizon terrestrial communication without repeatersa. 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 propagationa. 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 propagationa. 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 ofa. 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 ofa. 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 aa. 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 aa. windowb. critical frequencyc. gyro frequency ranged. Resonance in the atmosphere

8. Frequencies in the UHF range normally propagate by means ofa. ground wavesb. sky wavesc. surface wavesd. space waves

8. Frequencies in the UHF range normally propagate by means ofa. ground wavesb. sky wavesc. surface wavesd. space waves

9. Tropospheric scatter is used with frequencies in the following rangea. HFb. VHFc. UHFd. VLF

9. Tropospheric scatter is used with frequencies in the following rangea. HFb. VHFc. UHFd. VLF

10. The ground wave eventually disappears, as one moves away from the transmitter, because ofa. 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 ofa. interference from the sky waveb. loss of line of sight conditionsc. maximum single hop distance limitationsd. tilting

11. In electromagnetic waves, polarizationa. 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, polarizationa. 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 ona. 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 ona. their frequencyb. their distance from the transmitterc. the polarization of the wavesd. the polarization of the atmosphere

14. Electromagnetic waves are refracted when theya. pass into a medium of different dielectric constantb. are polarized at right angles to the direction of propagationc. encounter a perfectly conducting surfaced. pass through small slot in a conducting plane

14. Electromagnetic waves are refracted when theya. pass into a medium of different dielectric constantb. are polarized at right angles to the direction of propagationc. encounter a perfectly conducting surfaced. pass through small slot in a conducting plane

15. Diffraction of electromagnetic wavea. is caused by reflections from the groundb. arises only with the spherical wave frontsc. will occur when the waves pass through a large slotd. may occur around the edge of a sharp obstacle

15. Diffraction of electromagnetic wavea. is caused by reflections from the groundb. arises only with the spherical wave frontsc. will occur when the waves pass through a large slotd. may occur around the edge of a sharp obstacle

16. When microwave signals follow the curvature of the earth, this is known asa. the Faraday effectb. ductingc. troposheric scatterd. ionospheric reflections

16. When microwave signals follow the curvature of the earth, this is known asa. the Faraday effectb. ductingc. troposheric scatterd. ionospheric reflections

17. Helical antennas are often used for satellite tracking at VHF because ofa. troposcatterb. superrefractionc. ionospheric refractiond. the Faraday effect

17. Helical antennas are often used for satellite tracking at VHF because ofa. troposcatterb. superrefractionc. ionospheric refractiond. the Faraday effect

CHAPTER 9: ANTENNAS

1. An ungrounded antenna near the grounda. acts a single antenna of twice the heightb. is unlikely need an earth matc. acts as an antenna arrayd. must be horizontally polarized

1. An ungrounded antenna near the grounda. acts a single antenna of twice the heightb. is unlikely need an earth matc. acts as an antenna arrayd. must be horizontally polarized

2. One of the following consist of non resonant antennaa. rhombic antennab. folded dipolec. end fire arrayd. broadside array

2. One of the following consist of non resonant antennaa. 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 thea. conical hornb. folded dipolec. log-periodicd. square loop

3. One of the following is very useful as a multiband HF receiving antenna. This is thea. 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 falsea. impossibility of a good ground connectionb. protection of personnel working undergroundc. provision of an earth for the antennad. rockiness of the ground itself

5. Indicate which of the following reasons for using a counter poise with antenna is falsea. impossibility of a good ground connectionb. protection of personnel working undergroundc. provision of an earth for the antennad. 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 resistiveb. to provide the output amplifier with the correct load impedancec. to discriminate against harmonicsd. to prevent reradation 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 resistiveb. to provide the output amplifier with the correct load impedancec. to discriminate against harmonicsd. to prevent reradation 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 connectionb. 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 connectionb. 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 thea. helicalb. small circular loopc. parabolic reflectord. yagiuda

10. An antenna that is circularly polarized is thea. helicalb. small circular loopc. parabolic reflectord. yagiuda

11. The standard reference antenna for the directive gain is thea. infinitesimal dipoleb. isotropic antennac. elementary doubletd. half wave dipole

11. The standard reference antenna for the directive gain is thea. infinitesimal dipoleb. isotropic antennac. elementary doubletd. half wave dipole

12. Top loading is sometimes used with an antenna in order to increase itsa. effective heightb. bandwidthc. beam widthd. input capacitance

12. Top loading is sometimes used with an antenna in order to increase itsa. effective heightb. bandwidthc. beam widthd. input capacitance

13. Cassegrain feed is used with a parabolic reflector toa. 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 toa. 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 toa. 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 toa. 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 itsa. circular polarizationb. maneuverabilityc. broad bandwidthd. good front to back ratio

15. Helical antenna is used for satellite tracking because of itsa. 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 antennaa. Half wave dipoleb. Log periodicc. Disconed. Marconi

17. One of the following is not an omni directional antennaa. Half wave dipoleb. Log periodicc. Disconed. Marconi

CHAPTER 10: WAVEGUIDES, RESONATORS and COMPONENTS

1. When electromagnetic waves are propagated in a wave guidea. they travel along the broader walls of the guideb. they are reflected from the walls but do not travel along themc. they travel through the dielectric without touching the wallsd. they travel along all four walls of the waveguide

1. When electromagnetic waves are propagated in a wave guidea. they travel along the broader walls of the guideb. they are reflected from the walls but do not travel along themc. they travel through the dielectric without touching the wallsd. they travel along all four walls of the waveguide

2. Waveguides are used mainly for microwave signals becausea. the depend on the straight line propagation which applies to microwaves onlyb. losses would be to heavy at lower frequenciesc. there are no generators powerful enough to excite them at lower frequenciesd. they would be too bulky at lower frequencies

2. Waveguides are used mainly for microwave signals becausea. the depend on the straight line propagation which applies to microwaves onlyb. losses would be to heavy at lower frequenciesc. there are no generators powerful enough to excite them at lower frequenciesd. they would be too bulky at lower frequencies

3. The wavelength of a wave in a waveguidea. is greater than in free spaceb. depends only on the wave guide dimensions and the free space wavelengthc. is inversely proportional to the phase velocityd. is directly proportional to the group velocity

3. The wavelength of a wave in a waveguidea. is greater than in free spaceb. depends only on the wave guide dimensions and the free space wavelengthc. is inversely proportional to the phase velocityd. is directly proportional to the group velocity

4. The main difference between the operation of transmission lines and wave guides is thata. the latter are not distributed, like transmission linesb. the former can use stubs and quarter wave transformers, unlike the latterc. transmission lines use the principal mode of propagation, and therefore do not suffer from low frequency cut offd. 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 thata. the latter are not distributed, like transmission linesb. the former can use stubs and quarter wave transformers, unlike the latterc. transmission lines use the principal mode of propagation, and therefore do not suffer from low frequency cut offd. 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 isa. 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 isa. 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 isa. 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 isa. 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 calleda. 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 calleda. 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 guidea. the group velocity of the signal becomes zerob. the phase velocity of the signal becomes infinitec. the characteristic impedance of the guide becomes infinited. 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 guidea. the group velocity of the signal becomes zerob. the phase velocity of the signal becomes infinitec. the characteristic impedance of the guide becomes infinited. 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 isa. 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 isa. 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 dimensionsb. the resulting impedance can be matched directly to coaxial linesc. its is easier to excite than the other modesd. 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 dimensionsb. the resulting impedance can be matched directly to coaxial linesc. its is easier to excite than the other modesd. propagation of it without any spurious generation can be ensured

12. A choke flange may be used to couple two waveguidesa. to help in alignment of the waveguidesb. because it is simplier than any other joinc. to compensate for discontinuities at the joind. to increase the bandwidth of the system

12. A choke flange may be used to couple two waveguidesa. to help in alignment of the waveguidesb. because it is simplier than any other joinc. to compensate for discontinuities at the joind. 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 aa. 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 aa. 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 havea. a Q that is too lowb. a shape whose resonant frequency is too difficult to calculatec. harmonically related resonant frequenciesd. too heavy losses

16. Cylindrical cavity resonators are not used with klystrons because they havea. a Q that is too lowb. a shape whose resonant frequency is too difficult to calculatec. harmonically related resonant frequenciesd. too heavy losses

17. A directional coupler with three or more holes is sometimes used in preference to the two hole couplera. 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 couplera. 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 thea. curie temperatureb. saturation magnetizationc. line widthd. gyromagnetic resonance

20. The maximum power that may be handled by a ferrite component is limited by thea. 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 interferenceb. to allow the one antenna to be used for reception or transmission without mutual interferencec. To prevent interference between two antennas when they are connected to a receiverd. 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 interferenceb. to allow the one antenna to be used for reception or transmission without mutual interferencec. To prevent interference between two antennas when they are connected to a receiverd. to increase the speed of the pulses in pulsed radar

23. For some applications, circular waveguides may be preferred to rectangular ones because ofa. smaller cross section needed at any frequencyb. lower attenuationc. freedom from spurious modesd. rotation of polarization

23. For some applications, circular waveguides may be preferred to rectangular ones because ofa. smaller cross section needed at any frequencyb. 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 isa. circularb. ridgedc. rectangulard. flexible

25. In order to reduce cross sectional dimensions, the waveguide to use isa. circularb. ridgedc. rectangulard. flexible

26. For low attenuation, the best transmission medium isa. flexible waveguideb. ridged waveguidec. rectangular waveguided. coaxial line

26. For low attenuation, the best transmission medium isa. 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 thea. 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 thea. 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 thea. multicavityb. BWOc. CFAd. TWT

2. One of the following is unlikely to be used as a pulsed device. It is thea. multicavityb. BWOc. CFAd. TWT

3. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that theira. 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 theira. 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 ifa. the electrodes are brought closer togetherb. 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 ifa. the electrodes are brought closer togetherb. 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 toa. prevent the oscillations that occur in two cavity klystronb. increase the bandwidth of the devicec. improve the power gaind. increase the efficiency of the klystron

6. Indicate the false statement. Klystron may use intermediate cavities toa. prevent the oscillations that occur in two cavity klystronb. increase the bandwidth of the devicec. improve the power gaind. increase the efficiency of the klystron

7. The TWT is sometimes preferred to the multicavity klystron amplifier, because the formera. 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 formera. 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 + cycles to ensure thata. electrons are accelerated by the gap voltages on their returnb. returning electron give energy to gap oscillationsc. it is equal to the period of the cavity oscillationsd. the repeller is not damaged by the striking electrons

8. The transit time in the repeller space of a reflex klystron must be n + cycles to ensure thata. electrons are accelerated by the gap voltages on their returnb. returning electron give energy to gap oscillationsc. it is equal to the period of the cavity oscillationsd. the repeller is not damaged by the striking electrons

9. The cavity magnetron uses strapping toa. prevent mode jumpingb. prevent cathode back heatingc. ensure bunchingd. improve the phase focusing effect

9. The cavity magnetron uses strapping toa. prevent mode jumpingb. prevent cathode back heatingc. ensure bunchingd. improve the phase focusing effect

10. Magnetic field is used in the cavity magnetron toa. prevent anode current in absence of oscillationsb. ensure that the oscillations are pulsedc. help in focusing the electron beam, thus preventing spreadingd. ensure electrons will orbit around the cathode

10. Magnetic field is used in the cavity magnetron toa. prevent anode current in absence of oscillationsb. ensure that the oscillations are pulsedc. help in focusing the electron beam, thus preventing spreadingd. 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 thea. 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 thea. hole and slotb. slotc. vaned. rising sun

12. The primary purpose of the helix in a traveling wave tube is toa. prevent the electron beam from spreading in the long tubeb. reduce the axial velocity of the RF fieldc. ensure broadband operationd. reduce noise figure

12. The primary purpose of the helix in a traveling wave tube is toa. prevent the electron beam from spreading in the long tubeb. reduce the axial velocity of the RF fieldc. ensure broadband operationd. reduce noise figure

13. The attenuator is used in the traveling wave tube toa. help bunchingb. prevent oscillationsc. prevent saturationsd. increase gain

13. The attenuator is used in the traveling wave tube toa. help bunchingb. prevent oscillationsc. prevent saturationsd. increase gain

14. Periodic permanent magnet focusing is used with TWTs toa. 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 toa. 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 isa. 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 isa. 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 aa. coaxial magnetronb. dither-tuned amplifierc. frequency- agile magnetrond. VTM

16. Magnetron whose oscillating frequency is electronically adjustable over a wide range is called aa. 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 toa. help focusingb. provide attenuationc. improve bunchingd. increase gain

18. The glass tube of a TWT may be coated with aquadag toa. help focusingb. provide attenuationc. improve bunchingd. increase gain

19. Back ward wave oscillator is based on thea. rising sun magnetronb. crossed field amplifierc. coaxial magnetrond. traveling wave tube

19. Back ward wave oscillator is based on thea. rising sun magnetronb. crossed field amplifierc. coaxial magnetrond. traveling wave tube

CHAPTER 12: SEMICONDUCTOR MICROWAVE DEVICES ANDCIRCUITS

1. Parametric amplifier must be cooleda. because parametric amplification generates a lot of heatb. to increase bandwidthc. because it cannot operate at room temperatured. to improve the noise performance

1. Parametric amplifier must be cooleda. because parametric amplification generates a lot of heatb. to increase bandwidthc. because it cannot operate at room temperatured. to improve the noise performance

2. Ruby maser amplifier must be cooleda. because maser amplification generates a lot of heatb. to increase bandwidthc. because it cannot operate at room temperatured. to improve the noise performance

2. Ruby maser amplifier must be cooleda. because maser amplification generates a lot of heatb. to increase bandwidthc. because it cannot operate at room temperatured. to improve the noise performance

3. Disadvantage of microstrip compared with stripline is that microstripa. does not readily lend itself to printed circuit techniquesb. is more likely to radiatec. is bulkierd. is more expensive and complex to manufacture

3. Disadvantage of microstrip compared with stripline is that microstripa. does not readily lend itself to printed circuit techniquesb. is more likely to radiatec. is bulkierd. is more expensive and complex to manufacture

4. The transmission system using two ground planes isa. microstripb. elliptical waveguidec. parallel wire lined. stripline

4. The transmission system using two ground planes isa. microstripb. elliptical waveguidec. parallel wire lined. stripline

5. Indicate the false statement. An advantage of stripline over waveguides is itsa. 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 itsa. 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 itsa. easier integration with semiconductor devicesb. lower tendency to radiatec. higher isolation between adjacent circuitsd. higher Q

6. Indicate the false statement. An advantage of stripline over microstrip is itsa. easier integration with semiconductor devicesb. lower tendency to radiatec. higher isolation between adjacent circuitsd. higher Q

7. Surface acoustic waves propagate ina. gallium arsenideb. indium phosphidec. striplined. quartz crystal

7. Surface acoustic waves propagate ina. 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 theya. 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 theya. 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 usea. 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 usea. 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 itsa. 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 itsa. 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 outputa. Varactorb. Gunnc. Schottky barrierd. RIMPATT

12. Indicate which of the following diodes will produce the highest pulsed power outputa. 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 ina. germaniumb. gallium arsenidec. silicond. metal semiconductor, junctions

16. The transferred electron bulk effect occurs ina. germaniumb. gallium arsenidec. silicond. metal semiconductor, junctions

17. The gain bandwidth frequency of a microwave transistor, fT, is the frequency at which thea. alpha of the transistor falls by 3dBb. 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 thea. alpha of the transistor falls by 3dBb. 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 highb. a small value of base resistance is requiredc. a step recovery diode must be usedd. 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 highb. a small value of base resistance is requiredc. a step recovery diode must be usedd. 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 aa. 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 aa. 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 isa. Fib. 2Fic. Fi Fpd. Fp Fi

22. Non degenerate parametric amplifier has an input frequency Fi and a pump frequency Fp. The idler frequency isa. Fib. 2Fic. Fi Fpd. Fp Fi

23. Traveling wave parametric amplifiers are used toa. 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 toa. 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 toa. prevent noise feedbackb. allow the antenna to be used simultaneously for transmission and receptionc. separate the signal and idler frequenciesd. permit more efficient pumping

24. A parametric amplifier sometimes uses a circulator toa. prevent noise feedbackb. allow the antenna to be used simultaneously for transmission and receptionc. separate the signal and idler frequenciesd. permit more efficient pumping

25. The non degenerate one port parametric amplifier should have a high ratio of pump to signal frequency because thisa. permits satisfactory high frequency operationb. 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 thisa. permits satisfactory high frequency operationb. 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 toa. 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 toa. increase the frequency stabilityb. increase the availability negative resistancec. facilitate tunningd. allow operation at the highest frequencies

28. The negative resistance in a tunnel diodea. is maximum at the peak point of the characteristicb. is available between the peak and valley pointsc. is maximum at the valley pointd. may be improved by the use of reverse bias

28. The negative resistance in a tunnel diodea. is maximum at the peak point of the characteristicb. is available between the peak and valley pointsc. 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 aa. 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 aa. lower noiseb. higher ion mobilityc. larger voltage swingd. simpler fabrication process

30. Negative resistance is obtained with a Gunn diode because ofa. electron transfer to less mobile energy levelb. avalanche breakdown with the high voltage currentc. tunneling across the junctiond. electron domains forming at the junction

30. Negative resistance is obtained with a Gunn diode because ofa. electron transfer to less mobile energy levelb. avalanche breakdown with the high voltage currentc. tunneling across the junctiond. electron domains forming at the junction

31. For Gunn diodes, gallium arsenide is preferred to silicon because the formera. has suitable empty energy band, which silicon does not haveb. 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 formera. has suitable empty energy band, which silicon does not haveb. 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 itsa. lower efficiency than that of the other microwave diodesb. high noisec. inability to provide pulsed operationd. lower ability handling ability

32. The biggest disadvantage of IMPATT diode is itsa. lower efficiency than that of the other microwave diodesb. high noisec. inability to provide pulsed operationd. lower ability handling ability

33. The magnetic field is used with a ruby maser toa. provide sharp focusing for the electron beamb. increase the population inversionc. allow room temperature operationd. provide frequency adjustments

33. The magnetic field is used with a ruby maser toa. provide sharp focusing for the electron beamb. 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 hasa. 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 hasa. a much greater bandwidthb. a better frequency stabilityc. a low noise figured. no need for circulator

35. Parametric amplifiers and masers a re 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 the are one port devices

35. Parametric amplifiers and masers a re 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 the are one port devices

36. Maser RF amplifier is not really suitable fora. radio astronomyb. satellite communicationsc. radard. troposcatter receivers

36. Maser RF amplifier is not really suitable fora. radio astronomyb. satellite communicationsc. radard. troposcatter receivers

37. Th