Kennedy questions

1. Electronic Systems and Technology Compiled by: Aaron Agoot BSECE

2. CHAPTER 1: INTRODUCTION TO COMMUNICATION SYSTEM

3. 1. In a communication system, noise is most likely to affect the signal a. at the transmitter b. in the channel c. in the information source d. at the destination

4. 1. In a communication system, noise is most likely to affect the signal a. at the transmitter b. in the channel c. in the information source d. at the destination

5. 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

6. 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

7. 3. Indicate the false statement. Modulation is used to a. reduce the bandwidth used b. separate the differing transmissions c. ensure that intelligence may be transmitted over long distances d. allow the use of practicable antennas

8. 3. Indicate the false statement. Modulation is used to a. reduce the bandwidth used b. separate the differing transmissions c. ensure that intelligence may be transmitted over long distances d. allow the use of practicable antennas

9. 4. Indicate the false statement. From the transmitter the signal deterioration because of noise is usually a. unwanted energy b. predictable in character c. present in the transmitter d. due to any cause

10. 4. Indicate the false statement. From the transmitter the signal deterioration because of noise is usually a. unwanted energy b. predictable in character c. present in the transmitter d. due to any cause

11. 5. Indicate the true statement. Most receivers conforms to the a. amplitude-modulated group b. frequency-modulated group c. superheterodyne group d. tuned radio frequency receiver group

12. 5. Indicate the true statement. Most receivers conforms to the a. amplitude-modulated group b. frequency-modulated group c. superheterodyne group d. tuned radio frequency receiver group

13. 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

14. 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

15. 7. Indicate the true statement. The process of sending and receiving started as early as a. the middle 1930s b. 1850 c. the beginning of the twentieth century d. the 1840s

16. 7. Indicate the true statement. The process of sending and receiving started as early as a. the middle 1930s b. 1850 c. the beginning of the twentieth century d. the 1840s

17. 8. Which of the steps is not included in the process of reception? a. decoding b. encoding c. storage d. interpretation

18. 8. Which of the steps is not included in the process of reception? a. decoding b. encoding c. storage d. interpretation

19. 9. The acoustic channel is used for which of the following? a. UHF communications b. single-sideband communication c. television communications d. person-to-person voice communications.

20. 9. The acoustic channel is used for which of the following? a. UHF communications b. single-sideband communication c. television communications d. person-to-person voice communications.

21. 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 interruption d. frequency shift and phase shift

22. 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 interruption d. frequency shift and phase shift

23. CHAPTER 2: NOISE

24. 1. One of the following types of noise becomes a great importance at high frequencies. Is the a. shot noise b. random noise c. impulse noise d. transit-time noise

25. 1. One of the following types of noise becomes a great importance at high frequencies. Is the a. shot noise b. random noise c. impulse noise d. transit-time noise

26. 2. Indicate the false statement a. HF mixers are generally noisier than HF amplifiers b. Impulse noised voltage is independent of the bandwidth c. Thermal noise is independent of the frequency at which it is measured d. Industrial noise is usually of the impulse type

27. 2. Indicate the false statement a. HF mixers are generally noisier than HF amplifiers b. Impulse noised voltage is independent of the bandwidth c. Thermal noise is independent of the frequency at which it is measured d. Industrial noise is usually of the impulse type

28. 3. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore a. halved b. quadrupled c. double d. unchanged

29. 3. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore a. halved b. quadrupled c. double d. unchanged

30. 4. One of the following is not useful quantity for comparing the noise performance of the receiver a. Input noise voltage b. Equivalent noise resistance c. Noise temperature d. Noise figure

31. 4. One of the following is not useful quantity for comparing the noise performance of the receiver a. Input noise voltage b. Equivalent noise resistance c. Noise temperature d. Noise figure

32. 5. Indicate the noise whose source is in a category different from that of the other three. a. solar noise b. cosmic noise c. atmospheric noise d. galactic noise

33. 5. Indicate the noise whose source is in a category different from that of the other three. a. solar noise b. cosmic noise c. atmospheric noise d. galactic noise

34. 6. Indicate the false statement. The square of the thermal noise voltage generated by a resistor is proportional to a. its resistance b. its temperature c. Boltzmann’s Constant d. the bandwidth over which it is measured

35. 6. Indicate the false statement. The square of the thermal noise voltage generated by a resistor is proportional to a. its resistance b. its temperature c. Boltzmann’s Constant d. the bandwidth over which it is measured

36. 7. Which of the broad classifications of noise are most difficult to treat? a. noise generated in the receiver b. noise generated in the transmitter c. externally generated noise d. internally generated noise

37. 7. Which of the broad classifications of noise are most difficult to treat? a. noise generated in the receiver b. noise generated in the transmitter c. externally generated noise d. internally generated noise

38. 8. Space noise generally covers a wide frequency spectrum, but the strongest interference occurs a. between 8MHz and 1.43 GHz b. below 20 MHz c. between 20 to 120 MHz d. above 1.5 GHz

39. 8. Space noise generally covers a wide frequency spectrum, but the strongest interference occurs a. between 8MHz and 1.43 GHz b. below 20 MHz c. between 20 to 120 MHz d. above 1.5 GHz

40. 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

41. 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

42. 10. Which of the following is the most reliable measurement for comparing amplifier noise characteristics? a. signal-to-noise ratio b. noise factor c. shot noise d. thermal noise agitation

43. 10. Which of the following is the most reliable measurement for comparing amplifier noise characteristics? a. signal-to-noise ratio b. noise factor c. shot noise d. thermal noise agitation

44. 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

45. 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

46. CHAPTER 3: AMPLITUDE MODULATION

47. 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. 4V b. 3V c. 2V d. V

48. 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. 4V b. 3V c. 2V d. V

49. 2. In a low-level AM system, amplifiers following the modulated stage must be a. linear devices b. harmonic devices c. class C amplifiers d. non linear devices

50. 2. In a low-level AM system, amplifiers following the modulated stage must be a. linear devices b. harmonic devices c. class C amplifiers d. non linear devices

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

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

53. 4. Leak type bias is used in a plate modulated class C amplifier to a. prevent tuned circuit damping b. prevent excessive grid current c. prevent over modulation d. increase the bandwidth

54. 4. Leak type bias is used in a plate modulated class C amplifier to a. prevent tuned circuit damping b. prevent excessive grid current c. prevent over modulation d. increase the bandwidth

55. 5. The output stage of a television transmitter is most likely to be a a. plate modulated class C amplifier b. grid modulated class C amplifier c. screen modulated class C amplifier d. grid modulated class A amplifier

56. 5. The output stage of a television transmitter is most likely to be a a. plate modulated class C amplifier b. grid modulated class C amplifier c. screen modulated class C amplifier d. grid modulated class A amplifier

57. 6. The modulation index of an AM is changed from 0 to 1. The transmitted power is a. unchanged b. halved c. doubled d. increase by 50percent

58. 6. The modulation index of an AM is changed from 0 to 1. The transmitted power is a. unchanged b. halved c. doubled d. increase by 50percent

59. 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 transistor c. better efficiency d. better linearity

60. 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 transistor c. better efficiency d. better linearity

61. 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 1 b. cannot be calculated unless the phase relations are known c. is 0.5 d. is 0.7

62. 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 1 b. cannot be calculated unless the phase relations are known c. is 0.5 d. is 0.7

63. 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

64. 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

65. 10. What is the ratio of the modulating power to the total power at 100 percent modulation? a. 1:3 b. 1:2 c. 2:3 d. None of the above

66. 10. What is the ratio of the modulating power to the total power at 100 percent modulation? a. 1:3 b. 1:2 c. 2:3 d. None of the above

67. CHAPTER 4: SINGLE SIDE BAND TECHNIQUES

68. 1. Indicate the false statement regarding the advantages of SSB over double sideband, full carrier AM. a. More channel spaced available b. 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

69. 1. Indicate the false statement regarding the advantages of SSB over double sideband, full carrier AM. a. More channel spaced available b. 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

70. 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)

71. 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)

72. 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

73. 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

74. 4. The most common used filters in SSB generation are a. mechanical b. RC c. LC d. low-pass

75. 4. The most common used filters in SSB generation are a. mechanical b. RC c. LC d. low-pass

76. 5. In an SSB transmitter, one is most likely to find a a. class C audio amplifier b. tuned modulator c. class B RF amplifier d. class A RF output amplifier

77. 5. In an SSB transmitter, one is most likely to find a a. class C audio amplifier b. tuned modulator c. class B RF amplifier d. class A RF output amplifier

78. 6. Indicate in which of the following only one sideband is transmitted: a. H3E b. A3E c. B8E d. C3F

79. 6. Indicate in which of the following only one sideband is transmitted: a. H3E b. A3E c. B8E d. C3F

80. 7. One of the following cannot be used to remove unwanted sideband in SSB. This is the a. Filter system b. Phase shift method c. Third method d. Balance modulator

81. 7. One of the following cannot be used to remove unwanted sideband in SSB. This is the a. Filter system b. Phase shift method c. Third method d. Balance modulator

82. 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

83. 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

84. 9. To provide two or more voice circuits with the same carrier, it is necessary to use a. ISB b. Carrier reinsertion c. SSB with pilot carrier d. Lincompex

85. 9. To provide two or more voice circuits with the same carrier, it is necessary to use a. ISB b. Carrier reinsertion c. SSB with pilot carrier d. Lincompex

86. 10. Vestigial sideband modulation (C3F) is normally used for a. HF point to point communications b. Monoaural broadcasting c. TV broadcasting d. Stereo broadcasting

87. 10. Vestigial sideband modulation (C3F) is normally used for a. HF point to point communications b. Monoaural broadcasting c. TV broadcasting d. Stereo broadcasting

88. CHAPTER 5: FREQUENCY MODULATION

89. 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

90. 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

91. 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

92. 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

93. 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

94. 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

95. 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.

96. 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.

97. 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/3 b. mf c. 3mf d. 9mf

98. 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/3 b. mf c. 3mf d. 9mf

99. 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 δ b. Indeterminate c. δ / 5 d. δ

100. 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 δ b. Indeterminate c. δ / 5 d. δ

101. 7. A pre-emphasis circuit provides extra noise immunity by a. boosting the bass frequency b. amplifying the high audio frequencies c. preamplifying the whole audio band d. converting the phase modulation to FM

102. 7. A pre-emphasis circuit provides extra noise immunity by a. boosting the bass frequency b. amplifying the high audio frequencies c. preamplifying the whole audio band d. converting the phase modulation to FM

103. 8. Since noise phase modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude a. remains constant b. is decreased c. is increased d. is equalized

104. 8. Since noise phase modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude a. remains constant b. is decreased c. is increased d. is equalized

105. 9. When the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. The modulation system is a. amplitude modulation b. phase modulation c. frequency modulation d. any one of the three

106. 9. When the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. The modulation system is a. amplitude modulation b. phase modulation c. frequency modulation d. any one of the three

107. 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 required c. The transmitted power is more useful d. Less modulating power is required

108. 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 required c. The transmitted power is more useful d. Less modulating power is required

109. 11. One of the following is an in direct way of generating FM. This is the a. Reactance FET modulator b. Varactor diode c. Armstrong modulator d. Reactance bipolar transistor modulator

110. 11. One of the following is an in direct way of generating FM. This is the a. Reactance FET modulator b. Varactor diode c. Armstrong modulator d. Reactance bipolar transistor modulator

111. 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

112. 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

113. CHAPTER 6: RADIO RECEIVERS

114. 1. Indicate which of the following statement about the advantages of the phase discriminator over the slope detector is false: a. much easier alignment b. better linearity c. great limiting d. fewer tuned circuits

115. 1. Indicate which of the following statement about the advantages of the phase discriminator over the slope detector is false: a. much easier alignment b. better linearity c. great limiting d. fewer tuned circuits

116. 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 tuned d. leak type biased must be used

117. 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 tuned d. leak type biased must be used

118. 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

119. 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

120. 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

121. 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

122. 5. To prevent overloading of the last IF amplifier in the receiver, one should use a. squelch b. variable sensitivity c. variable selectivity d. double conversion

123. 5. To prevent overloading of the last IF amplifier in the receiver, one should use a. squelch b. variable sensitivity c. variable selectivity d. double conversion

124. 6. A super heterodyne receiver with an IF of 450KHz is tuned to a signal at 1200KHz. The image frequency is a. 750KHz b. 900KHz c. 1650KHz d. 2100KHz

125. 6. A super heterodyne receiver with an IF of 450KHz is tuned to a signal at 1200KHz. The image frequency is a. 750KHz b. 900KHz c. 1650KHz d. 2100KHz

126. 7. In a radio detector a. the linearity is worse than in phase discriminator b. stabilization against signal strength variations is provided c. 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

127. 7. In a radio detector a. the linearity is worse than in phase discriminator b. stabilization against signal strength variations is provided c. 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

128. 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

129. 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

130. 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

131. 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

132. 10. The controlled oscillator synthesizer is sometimes preferred to the direct one because a. it is simpler piece of equipment b. its frequency stability is better c. it does not require crystal oscillators d. it is relatively free of spurious frequencies

135. 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 decades d. reduce the number of crystal required

136. 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 decades d. reduce the number of crystal required

137. 12. Indicated which of the following circuits could not demodulate SSB. a. Balance modulator b. Product detector c. BFO d. Phase discriminator

138. 12. Indicated which of the following circuits could not demodulate SSB. a. Balance modulator b. Product detector c. BFO d. Phase discriminator

139. 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

140. 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

141. 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 sensitivity c. inadequate selectivity at high frequencies d. instability

142. 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 sensitivity c. inadequate selectivity at high frequencies d. instability

143. 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

144. 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

145. 16. One of the main functions of the RF amplifier in a super heterodyne receiver is to a. provide improved tracking b. permit better adjacent-channel rejection c. increase the tuning range of the receiver d. improve the rejection of the image frequency

146. 16. One of the main functions of the RF amplifier in a super heterodyne receiver is to a. provide improved tracking b. permit better adjacent-channel rejection c. increase the tuning range of the receiver d. improve the rejection of the image frequency

147. 17. A receiver has poor IF selectivity. It will therefore also have poor a. blocking b. double spotting c. diversity reception d. sensitivity

148. 17. A receiver has poor IF selectivity. It will therefore also have poor a. blocking b. double spotting c. diversity reception d. sensitivity

149. 18. Three point tracking is achieved with a. variable selectivity b. the padder capacitor c. double spotting d. double conversion

150. 18. Three point tracking is achieved with a. variable selectivity b. the padder capacitor c. double spotting d. double conversion

151. 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 tracking c. because otherwise an intermediate frequency could not be produced d. to allow adequate frequency coverage without switching

152. 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 tracking c. because otherwise an intermediate frequency could not be produced d. to allow adequate frequency coverage without switching

153. 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 poor d. tracking will be improved

154. 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 poor d. tracking will be improved

155. 21. A low ratio of the AC to the DC load impedance of a diode detector results in a. diagonal clipping b. poor AGC operation c. negative-peak clipping d. poor AF response

156. 21. A low ratio of the AC to the DC load impedance of a diode detector results in a. diagonal clipping b. poor AGC operation c. negative-peak clipping d. poor AF response

157. 22. On of the following cannot be used to demodulate SSB. a. product detector b. diode balance modulator c. bipolar transistor balance modulator d. complete phase-shift generator

158. 22. On of the following cannot be used to demodulate SSB. a. product detector b. diode balance modulator c. bipolar transistor balance modulator d. complete phase-shift generator

159. 23. Indicate the false statement. Nothing 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

160. 23. Indicate the false statement. Nothing 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

161. 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

162. 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

163. 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 carrier c. ISB d. Single sideband, full carrier

164. 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 carrier c. ISB d. Single sideband, full carrier

165. CHAPTER 7: TRANSMISSION LINES

166. 1. Indicate the false statement. The SWR on a transmission line infinity; the line is terminated in a. a short circuit b. a complex impedance c. an open circuit d. a pure resistance

167. 1. Indicate the false statement. The SWR on a transmission line infinity; the line is terminated in a. a short circuit b. a complex impedance c. an open circuit d. a pure resistance

168. 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 load b. an inductance at the load c. a capacitance at some specific distance from the load d. a short circuited stub at some specific distance from the load

169. 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 load b. an inductance at the load c. a capacitance at some specific distance from the load d. a short circuited stub at some specific distance from the load

170. 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 effect d. is higher for a solid dielectric than for air

171. 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 effect d. is higher for a solid dielectric than for air

172. 4. Impedance inversion may be obtained with a. a short circuited stub b. an open circuited stub c. a quarter wave line d. a half wave line

173. 4. Impedance inversion may be obtained with a. a short circuited stub b. an open circuited stub c. a quarter wave line d. a half wave line

174. 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 radiate d. incapable of giving a full range of reactance

175. 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 radiate d. incapable of giving a full range of reactance

176. 6. For a transmission line load matching over a range of frequencies, it is best to use a a. balun b. broadband directional coupler c. double stub d. single stud of adjustable position

177. 6. For a transmission line load matching over a range of frequencies, it is best to use a a. balun b. broadband directional coupler c. double stub d. single stud of adjustable position

178. 7. The main disadvantage of the two hole directional couple is a. low directional coupling b. poor directivity c. high SWR d. narrow bandwidth

179. 7. The main disadvantage of the two hole directional couple is a. low directional coupling b. poor directivity c. high SWR d. narrow bandwidth

180. 8. To couple a coaxial line to a parallel wire, it is best to use a a. slotted line b. balun c. directional coupler d. quarter wave transformer

181. 8. To couple a coaxial line to a parallel wire, it is best to use a a. slotted line b. balun c. directional coupler d. quarter wave transformer

182. 9. Indicate the three types of transmission line energy losses a. (I^2)R, RL, and temperature b. Radiation, (I^2)R, and dielectric heating c. Dielectric separation, insulation breakdown, and radiation d. Conductor heating, dielectric heating, and radiation resistance

183. 9. Indicate the three types of transmission line energy losses a. (I^2)R, RL, and temperature b. Radiation, (I^2)R, and dielectric heating c. Dielectric separation, insulation breakdown, and radiation d. Conductor heating, dielectric heating, and radiation resistance

184. 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

185. 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

186. CHAPTER 8: RADIATION AND PROPAGATION OF WAVES

187. 1. Indicated which one of the following terms applies to troposcatter propagation: a. SIDs b. Fading c. Atmospheric storms d. Faraday Rotation

188. 1. Indicated which one of the following terms applies to troposcatter propagation: a. SIDs b. Fading c. Atmospheric storms d. Faraday Rotation

189. 2. VLF waves are used for some types of services because a. of the low powers required b. the transmitting antennas are of convenient size c. they are very reliable d. they penetrate the ionosphere easily

190. 2. VLF waves are used for some types of services because a. of the low powers required b. the transmitting antennas are of convenient size c. they are very reliable d. they penetrate the ionosphere easily

191. 3. Indicate which of the following frequencies cannot be used for reliable beyond the horizon terrestrial communication without repeaters a. 20KHz b. 15MHz c. 900MHz d. 12GHz

192. 3. Indicate which of the following frequencies cannot be used for reliable beyond the horizon terrestrial communication without repeaters a. 20KHz b. 15MHz c. 900MHz d. 12GHz

193. 4. High frequency waves are a. absorbed by the F2 layer b. reflected by the D layer c. capable of use for long distance communication on the moon d. affected by the solar cycle

194. 4. High frequency waves are a. absorbed by the F2 layer b. reflected by the D layer c. capable of use for long distance communication on the moon d. affected by the solar cycle

195. 5. Distances near the skip distance should be used for the sky-wave propagation a. to avoid tilting b. to prevent sky-wave and upper ray interference c. to avoid the Faraday effect d. so as not to exceed the critical frequency

196. 5. Distances near the skip distance should be used for the sky-wave propagation a. to avoid tilting b. to prevent sky-wave and upper ray interference c. to avoid the Faraday effect d. so as not to exceed the critical frequency

197. 6. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of a. a more directional antennas b. broadband antennas c. frequency diversity d. space diversity

198. 6. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of a. a more directional antennas b. broadband antennas c. frequency diversity d. space diversity

199. 7. A range of microwave frequency more easily passed by the atmosphere than the other is called a a. window b. critical frequency c. gyro frequency range d. Resonance in the atmosphere

200. 7. A range of microwave frequency more easily passed by the atmosphere than the other is called a a. window b. critical frequency c. gyro frequency range d. Resonance in the atmosphere

201. 8. Frequencies in the UHF range normally propagate by means of a. ground waves b. sky waves c. surface waves d. space waves

202. 8. Frequencies in the UHF range normally propagate by means of a. ground waves b. sky waves c. surface waves d. space waves

203. 9. Tropospheric scatter is used with frequencies in the following range a. HF b. VHF c. UHF d. VLF

204. 9. Tropospheric scatter is used with frequencies in the following range a. HF b. VHF c. UHF d. VLF

205. 10. The ground wave eventually disappears, as one moves away from the transmitter, because of a. interference from the sky wave b. loss of line of sight conditions c. maximum single hop distance limitations d. tilting

206. 10. The ground wave eventually disappears, as one moves away from the transmitter, because of a. interference from the sky wave b. loss of line of sight conditions c. maximum single hop distance limitations d. tilting

207. 11. In electromagnetic waves, polarization a. is caused by reflection b. is due to the transverse nature of the waves c. results from the longitudinal nature of waves d. is always vertical in an isotropic antenna

208. 11. In electromagnetic waves, polarization a. is caused by reflection b. is due to the transverse nature of the waves c. results from the longitudinal nature of waves d. is always vertical in an isotropic antenna

209. 12. As electromagnetic waves travel in free space, one the following can happen to them: a. absorption b. attenuation c. refraction d. reflection

210. 12. As electromagnetic waves travel in free space, one the following can happen to them: a. absorption b. attenuation c. refraction d. reflection

211. 13. The absorption of radio waves by the atmosphere depends on a. their frequency b. their distance from the transmitter c. the polarization of the waves d. the polarization of the atmosphere

212. 13. The absorption of radio waves by the atmosphere depends on a. their frequency b. their distance from the transmitter c. the polarization of the waves d. the polarization of the atmosphere

213. 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

214. 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

215. 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

216. 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

217. 16. When microwave signals follow the curvature of the earth, this is known as a. the Faraday effect b. ducting c. troposheric scatter d. ionospheric reflections

218. 16. When microwave signals follow the curvature of the earth, this is known as a. the Faraday effect b. ducting c. troposheric scatter d. ionospheric reflections

219. 17. Helical antennas are often used for satellite tracking at VHF because of a. troposcatter b. superrefraction c. ionospheric refraction d. the Faraday effect

220. 17. Helical antennas are often used for satellite tracking at VHF because of a. troposcatter b. superrefraction c. ionospheric refraction d. the Faraday effect

221. CHAPTER 9: ANTENNAS

222. 1. An ungrounded antenna near the ground a. acts a single antenna of twice the height b. is unlikely need an earth mat c. acts as an antenna array d. must be horizontally polarized

223. 1. An ungrounded antenna near the ground a. acts a single antenna of twice the height b. is unlikely need an earth mat c. acts as an antenna array d. must be horizontally polarized

224. 2. One of the following consist of non resonant antenna a. rhombic antenna b. folded dipole c. end fire array d. broadside array

225. 2. One of the following consist of non resonant antenna a. rhombic antenna b. folded dipole c. end fire array d. broadside array

226. 3. One of the following is very useful as a multiband HF receiving antenna. This is the a. conical horn b. folded dipole c. log-periodic d. square loop

227. 3. One of the following is very useful as a multiband HF receiving antenna. This is the a. conical horn b. folded dipole c. log-periodic d. square loop

228. 4. Which of the following antenna is best excited from a waveguide? a. biconical b. horn c. helical d. discone

229. 4. Which of the following antenna is best excited from a waveguide? a. biconical b. horn c. helical d. discone

230. 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

231. 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

232. 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 reradation of the local oscillator

233. 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 reradation of the local oscillator

234. 7. Indicate the antenna that is not wideband: a. Discone b. Folded dipole c. Helical d. Marconi

235. 7. Indicate the antenna that is not wideband: a. Discone b. Folded dipole c. Helical d. Marconi

236. 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 antenna c. protection of personnel working underneath d. improvement of radiation pattern of the antenna

237. 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 antenna c. protection of personnel working underneath d. improvement of radiation pattern of the antenna

238. 9. Which one of the following terms does not apply the yagi-uda array? a. good bandwidth b. parasitic elements c. folded dipole d. high gain

239. 9. Which one of the following terms does not apply the yagi-uda array? a. good bandwidth b. parasitic elements c. folded dipole d. high gain

240. 10. An antenna that is circularly polarized is the a. helical b. small circular loop c. parabolic reflector d. yagi–uda

241. 10. An antenna that is circularly polarized is the a. helical b. small circular loop c. parabolic reflector d. yagi–uda

242. 11. The standard reference antenna for the directive gain is the a. infinitesimal dipole b. isotropic antenna c. elementary doublet d. half wave dipole

243. 11. The standard reference antenna for the directive gain is the a. infinitesimal dipole b. isotropic antenna c. elementary doublet d. half wave dipole

244. 12. Top loading is sometimes used with an antenna in order to increase its a. effective height b. bandwidth c. beam width d. input capacitance

245. 12. Top loading is sometimes used with an antenna in order to increase its a. effective height b. bandwidth c. beam width d. input capacitance

246. 13. Cassegrain feed is used with a parabolic reflector to a. increase the gain of the system b. increase the beam width of the system c. reduce the size of the main reflector d. allow the feed to be placed at a convenient point

247. 13. Cassegrain feed is used with a parabolic reflector to a. increase the gain of the system b. increase the beam width of the system c. reduce the size of the main reflector d. allow the feed to be placed at a convenient point

248. 14. Zoning is used with a dielectric antenna in order to a. reduce the bulk of the lens b. increase the bandwidth of the lens c. permit pin point focusing d. correct the curvature of the wave front from a horn that is too short

249. 14. Zoning is used with a dielectric antenna in order to a. reduce the bulk of the lens b. increase the bandwidth of the lens c. permit pin point focusing d. correct the curvature of the wave front from a horn that is too short

250. 15. Helical antenna is used for satellite tracking because of its a. circular polarization b. maneuverability c. broad bandwidth d. good front to back ratio

251. 15. Helical antenna is used for satellite tracking because of its a. circular polarization b. maneuverability c. broad bandwidth d. good front to back ratio

252. 16. The discone antenna is a. a useful direction finding antenna b. used as a radar receiving antenna c. circularly polarized like other circular antennas d. useful as a UHF receiving antenna

253. 16. The discone antenna is a. a useful direction finding antenna b. used as a radar receiving antenna c. circularly polarized like other circular antennas d. useful as a UHF receiving antenna

254. 17. One of the following is not an omni directional antenna a. Half wave dipole b. Log periodic c. Discone d. Marconi

255. 17. One of the following is not an omni directional antenna a. Half wave dipole b. Log periodic c. Discone d. Marconi

256. CHAPTER 10: WAVEGUIDES, RESONATORS and COMPONENTS

257. 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

258. 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

259. 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

260. 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

261. 3. The wavelength of a wave in a waveguide a. is greater than in free space b. 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

262. 3. The wavelength of a wave in a waveguide a. is greater than in free space b. 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

263. 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

264. 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

265. 5. Compared with the equivalent transmission line, 3GHz waveguides (indicate the false statement) a. are less lossy b. can carry high powers c. are less bulky d. have lower attenuation

266. 5. Compared with the equivalent transmission line, 3GHz waveguides (indicate the false statement) a. are less lossy b. can carry high powers c. are less bulky d. have lower attenuation

267. 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-electric b. transverse-magnetic c. longitudinal d. transverse-electromagnetic

268. 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-electric b. transverse-magnetic c. longitudinal d. transverse-electromagnetic

269. 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 space b. the same as the wavelength perpendicular to the wall c. shortened because of the Doppler effect d. greater than in the actual direction of propagation

270. 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 space b. the same as the wavelength perpendicular to the wall c. shortened because of the Doppler effect d. greater than in the actual direction of propagation

271. 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 propagation b. normal velocity c. group velocity d. phase velocity

272. 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 propagation b. normal velocity c. group velocity d. phase velocity

273. 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

274. 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

275. 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 1,1 b. TE 1,0 c. TM 2,2 d. TE 2,0

276. 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 1,1 b. TE 1,0 c. TM 2,2 d. TE 2,0

277. 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

278. 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

279. 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

280. 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

281. 13. In order to couple two generators to a waveguide system without coupling them to each other, one could not use a a. rat race b. E – plane T c. Hybrid ring d. Magic T

282. 13. In order to couple two generators to a waveguide system without coupling them to each other, one could not use a a. rat race b. E – plane T c. Hybrid ring d. Magic T

283. 14. Which of the following waveguide tuning components is not easily adjustable? a. screw b. stub c. iris d. plunger

284. 14. Which of the following waveguide tuning components is not easily adjustable? a. screw b. stub c. iris d. plunger

285. 15. A piston attenuator is a a. vane attenuator b. waveguide below cutoff c. mode filter d. flap attenuator

286. 15. A piston attenuator is a a. vane attenuator b. waveguide below cutoff c. mode filter d. flap attenuator

287. 16. Cylindrical cavity resonators are not used with klystrons because they have a. a Q that is too low b. a shape whose resonant frequency is too difficult to calculate c. harmonically related resonant frequencies d. too heavy losses

288. 16. Cylindrical cavity resonators are not used with klystrons because they have a. a Q that is too low b. a shape whose resonant frequency is too difficult to calculate c. harmonically related resonant frequencies d. too heavy losses

289. 17. A directional coupler with three or more holes is sometimes used in preference to the two hole coupler a. because it is more efficient b. to increase coupling of the signal c. to reduce spurious mode generation d. to increase the bandwidth of the system

290. 17. A directional coupler with three or more holes is sometimes used in preference to the two hole coupler a. because it is more efficient b. to increase coupling of the signal c. to reduce spurious mode generation d. to increase the bandwidth of the system

291. 18. A ferrite is a. a non conductor with magnetic properties b. an intermetallic compound with particularly good conductivity c. an insulator which heavily attenuates magnetic fields d. a microwave semiconductor invented by faraday

292. 18. A ferrite is a. a non conductor with magnetic properties b. an intermetallic compound with particularly good conductivity c. an insulator which heavily attenuates magnetic fields d. a microwave semiconductor invented by faraday

293. 19. Manganese ferrite may be used as a (false) a. circulator b. isolator c. garnet d. phase shifter

294. 19. Manganese ferrite may be used as a (false) a. circulator b. isolator c. garnet d. phase shifter

295. 20. The maximum power that may be handled by a ferrite component is limited by the a. curie temperature b. saturation magnetization c. line width d. gyromagnetic resonance

296. 20. The maximum power that may be handled by a ferrite component is limited by the a. curie temperature b. saturation magnetization c. line width d. gyromagnetic resonance

297. 21. A PIN diode is a. a metal semiconductor point contact diode b. a microwave mixer diode c. often used as a microwave detector d. suitable for the use as a microwave switch

298. 21. A PIN diode is a. a metal semiconductor point contact diode b. a microwave mixer diode c. often used as a microwave detector d. suitable for the use as a microwave switch

299. 22. A duplexer is used a. 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

300. 22. A duplexer is used a. 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

301. 23. For some applications, circular waveguides may be preferred to rectangular ones because of a. smaller cross section needed at any frequency b. lower attenuation c. freedom from spurious modes d. rotation of polarization

302. 23. For some applications, circular waveguides may be preferred to rectangular ones because of a. smaller cross section needed at any frequency b. lower attenuation c. freedom from spurious modes d. rotation of polarization

303. 24. Indicate which of the following cannot be followed by the word “waveguide”: a. Elliptical b. Flexible c. Coaxial d. Ridged

304. 24. Indicate which of the following cannot be followed by the word “waveguide”: a. Elliptical b. Flexible c. Coaxial d. Ridged

305. 25. In order to reduce cross sectional dimensions, the waveguide to use is a. circular b. ridged c. rectangular d. flexible

306. 25. In order to reduce cross sectional dimensions, the waveguide to use is a. circular b. ridged c. rectangular d. flexible

307. 26. For low attenuation, the best transmission medium is a. flexible waveguide b. ridged waveguide c. rectangular waveguide d. coaxial line

308. 26. For low attenuation, the best transmission medium is a. flexible waveguide b. ridged waveguide c. rectangular waveguide d. coaxial line

309. CHAPTER 11: MICROWAVE TUBES AND CIRCUITS

310. 1. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the a. reflex klystron b. coaxial magnetron c. traveling wave tube magnetron d. CFA

311. 1. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the a. reflex klystron b. coaxial magnetron c. traveling wave tube magnetron d. CFA

312. 2. One of the following is unlikely to be used as a pulsed device. It is the a. multicavity b. BWO c. CFA d. TWT

313. 2. One of the following is unlikely to be used as a pulsed device. It is the a. multicavity b. BWO c. CFA d. TWT

314. 3. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their a. noise figure increases b. transit time becomes to short c. shunt capacitive reactance becomes too large d. series inductive reactance becomes too small

315. 3. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their a. noise figure increases b. transit time becomes to short c. shunt capacitive reactance becomes too large d. series inductive reactance becomes too small

316. 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 used c. multiple or coaxial leads are used d. the anode voltage is made larger

317. 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 used c. multiple or coaxial leads are used d. the anode voltage is made larger

318. 5. The Multicavity klystron a. is not a good low level amplifier because of noise b. has a high repeller voltage to ensure a rapid transit time c. is not suitable for pulsed operation d. needs a long transit time through the buncher cavity to ensure current modulation

319. 5. The Multicavity klystron a. is not a good low level amplifier because of noise b. has a high repeller voltage to ensure a rapid transit time c. is not suitable for pulsed operation d. needs a long transit time through the buncher cavity to ensure current modulation

320. 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 gain d. increase the efficiency of the klystron

321. 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 gain d. increase the efficiency of the klystron

322. 7. The TWT is sometimes preferred to the multicavity klystron amplifier, because the former a. is more efficient b. has a greater bandwidth c. has a higher number of modes d. produces a higher output power

323. 7. The TWT is sometimes preferred to the multicavity klystron amplifier, because the former a. is more efficient b. has a greater bandwidth c. has a higher number of modes d. produces a higher output power

324. 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

325. 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

326. 9. The cavity magnetron uses strapping to a. prevent mode jumping b. prevent cathode back heating c. ensure bunching d. improve the phase focusing effect

327. 9. The cavity magnetron uses strapping to a. prevent mode jumping b. prevent cathode back heating c. ensure bunching d. improve the phase focusing effect

328. 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

329. 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

330. 11. To avoid difficulties with strapping at high frequencies, the type of cavity structure used in the magnetron is the a. hole and slot b. slot c. vane d. rising sun

331. 11. To avoid difficulties with strapping at high frequencies, the type of cavity structure used in the magnetron is the a. hole and slot b. slot c. vane d. rising sun

332. 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 operation d. reduce noise figure

333. 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 operation d. reduce noise figure

334. 13. The attenuator is used in the traveling wave tube to a. help bunching b. prevent oscillations c. prevent saturations d. increase gain

335. 13. The attenuator is used in the traveling wave tube to a. help bunching b. prevent oscillations c. prevent saturations d. increase gain

336. 14. Periodic permanent magnet focusing is used with TWTs to a. allow pulsed operation b. improve electron bunching c. avoid the bulk of an electromagnet d. allow coupled cavity operation at highest frequencies

337. 14. Periodic permanent magnet focusing is used with TWTs to a. allow pulsed operation b. improve electron bunching c. avoid the bulk of an electromagnet d. allow coupled cavity operation at highest frequencies

338. 15. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is a. capable of longer duty cycle b. more efficient amplifier c. more broadband d. less noisy

339. 15. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is a. capable of longer duty cycle b. more efficient amplifier c. more broadband d. less noisy

340. 16. Magnetron whose oscillating frequency is electronically adjustable over a wide range is called a a. coaxial magnetron b. dither-tuned amplifier c. frequency- agile magnetron d. VTM

341. 16. Magnetron whose oscillating frequency is electronically adjustable over a wide range is called a a. coaxial magnetron b. dither-tuned amplifier c. frequency- agile magnetron d. VTM

342. 17. Indicate which of the following is not TWT slow rate structure: a. periodic permanent magnet b. coupled cavity c. helix d. ring bar

343. 17. Indicate which of the following is not TWT slow rate structure: a. periodic permanent magnet b. coupled cavity c. helix d. ring bar

344. 18. The glass tube of a TWT may be coated with aquadag to a. help focusing b. provide attenuation c. improve bunching d. increase gain

345. 18. The glass tube of a TWT may be coated with aquadag to a. help focusing b. provide attenuation c. improve bunching d. increase gain

346. 19. Back ward wave oscillator is based on the a. rising sun magnetron b. crossed field amplifier c. coaxial magnetron d. traveling wave tube

347. 19. Back ward wave oscillator is based on the a. rising sun magnetron b. crossed field amplifier c. coaxial magnetron d. traveling wave tube

348. CHAPTER 12: SEMICONDUCTOR MICROWAVE DEVICES AND CIRCUITS

349. 1. Parametric amplifier must be cooled a. because parametric amplification generates a lot of heat b. to increase bandwidth c. because it cannot operate at room temperature d. to improve the noise performance

350. 1. Parametric amplifier must be cooled a. because parametric amplification generates a lot of heat b. to increase bandwidth c. because it cannot operate at room temperature d. to improve the noise performance

351. 2. Ruby maser amplifier must be cooled a. because maser amplification generates a lot of heat b. to increase bandwidth c. because it cannot operate at room temperature d. to improve the noise performance

352. 2. Ruby maser amplifier must be cooled a. because maser amplification generates a lot of heat b. to increase bandwidth c. because it cannot operate at room temperature d. to improve the noise performance

353. 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 radiate c. is bulkier d. is more expensive and complex to manufacture

354. 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 radiate c. is bulkier d. is more expensive and complex to manufacture

355. 4. The transmission system using two ground planes is a. microstrip b. elliptical waveguide c. parallel wire line d. stripline

356. 4. The transmission system using two ground planes is a. microstrip b. elliptical waveguide c. parallel wire line d. stripline

357. 5. Indicate the false statement. An advantage of stripline over waveguides is its a. smaller bulk b. greater bandwidth c. higher power handling capability d. greater compatibility with solid state devices

358. 5. Indicate the false statement. An advantage of stripline over waveguides is its a. smaller bulk b. greater bandwidth c. higher power handling capability d. greater compatibility with solid state devices

359. 6. Indicate the false statement. An advantage of stripline over microstrip is its a. easier integration with semiconductor devices b. lower tendency to radiate c. higher isolation between adjacent circuits d. higher Q

360. 6. Indicate the false statement. An advantage of stripline over microstrip is its a. easier integration with semiconductor devices b. lower tendency to radiate c. higher isolation between adjacent circuits d. higher Q

361. 7. Surface acoustic waves propagate in a. gallium arsenide b. indium phosphide c. stripline d. quartz crystal

362. 7. Surface acoustic waves propagate in a. gallium arsenide b. indium phosphide c. stripline d. quartz crystal

363. 8. SAW devices may be used as a. transmission media like stripline b. filters c. UHF amplifiers d. Oscillators at millimeter frequencies

364. 8. SAW devices may be used as a. transmission media like stripline b. filters c. UHF amplifiers d. Oscillators at millimeter frequencies

365. 9. Indicate the false statement. FETs are preferred to bipolar transistor at the high frequencies because they a. are less noisy b. lend themselves more readily to integration c. are capable of higher efficiencies d. can provide higher gains

366. 9. Indicate the false statement. FETs are preferred to bipolar transistor at the high frequencies because they a. are less noisy b. lend themselves more readily to integration c. are capable of higher efficiencies d. can provide higher gains

367. 10. For best low level noise performance in the X-band, an amplifier should use a. a bipolar transistor b. a Gunn diode c. a step-recovery diode d. an IMPATT diode

368. 10. For best low level noise performance in the X-band, an amplifier should use a. a bipolar transistor b. a Gunn diode c. a step-recovery diode d. an IMPATT diode

369. 11. The biggest advantage of the TRAPATT diode over the IMPATT diode is its a. low noise b. higher efficiency c. ability to operate at higher frequencies d. lesser sensitivity to harmonics

370. 11. The biggest advantage of the TRAPATT diode over the IMPATT diode is its a. low noise b. higher efficiency c. ability to operate at higher frequencies d. lesser sensitivity to harmonics

371. 12. Indicate which of the following diodes will produce the highest pulsed power output a. Varactor b. Gunn c. Schottky barrier d. RIMPATT

372. 12. Indicate which of the following diodes will produce the highest pulsed power output a. Varactor b. Gunn c. Schottky barrier d. RIMPATT

373. 13. Indicate which of the following diodes does not use negative resistance in its operation: a. Backward b. Gunn c. IMPATT d. Tunnel

374. 13. Indicate which of the following diodes does not use negative resistance in its operation: a. Backward b. Gunn c. IMPATT d. Tunnel

375. 14. One of the following is not used as a microwave mixer or detector. a. crystal diode b. schottky barrier diode c. backward diode d. PIN diode

376. 14. One of the following is not used as a microwave mixer or detector. a. crystal diode b. schottky barrier diode c. backward diode d. PIN diode

377. 15. One of the following microwave diodes is suitable for very low power oscillations only: a. tunnel b. avalanche c. Gunn d. IMPATT

378. 15. One of the following microwave diodes is suitable for very low power oscillations only: a. tunnel b. avalanche c. Gunn d. IMPATT

379. 16. The transferred electron bulk effect occurs in a. germanium b. gallium arsenide c. silicon d. metal semiconductor, junctions

380. 16. The transferred electron bulk effect occurs in a. germanium b. gallium arsenide c. silicon d. metal semiconductor, junctions

381. 17. The gain bandwidth frequency of a microwave transistor, f T , is the frequency at which the a. alpha of the transistor falls by 3dB b. beta of the transistor falls by 3dB c. power gain of the transistor falls to unity d. beta of the transistor falls to unity

382. 17. The gain bandwidth frequency of a microwave transistor, f T , is the frequency at which the a. alpha of the transistor falls by 3dB b. beta of the transistor falls by 3dB c. power gain of the transistor falls to unity d. beta of the transistor falls to unity

383. 18. For microwave transistor to operate at the high frequencies, the (false) a. collector voltage must be large b. collector current must be high c. base should be thin d. emitter area must be large

384. 18. For microwave transistor to operate at the high frequencies, the (false) a. collector voltage must be large b. collector current must be high c. base should be thin d. emitter area must be large

385. 19. Varactor diode may be useful at microwave frequencies (false) a. for electronic tuning b. for frequency multiplication c. as an oscillator d. as a parametric amplifier

386. 19. Varactor diode may be useful at microwave frequencies (false) a. for electronic tuning b. for frequency multiplication c. as an oscillator d. as a parametric amplifier

387. 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

388. 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

389. 21. Parametric amplifier has an input and output frequency of 2.25GHz and is pumped at 4.5GHz. It is a a. traveling wave amplifier b. degenerative amplifier c. lower sideband up converter d. upper sideband up converter

390. 21. Parametric amplifier has an input and output frequency of 2.25GHz and is pumped at 4.5GHz. It is a a. traveling wave amplifier b. degenerative amplifier c. lower sideband up converter d. upper sideband up converter

391. 22. Non degenerate parametric amplifier has an input frequency Fi and a pump frequency Fp. The idler frequency is a. Fi b. 2Fi c. Fi – Fp d. Fp – Fi

392. 22. Non degenerate parametric amplifier has an input frequency Fi and a pump frequency Fp. The idler frequency is a. Fi b. 2Fi c. Fi – Fp d. Fp – Fi

393. 23. Traveling wave parametric amplifiers are used to a. provide a greater gain b. reduce the number of varactor diodes required c. avoid the need for cooling d. provide a greater bandwidth

394. 23. Traveling wave parametric amplifiers are used to a. provide a greater gain b. reduce the number of varactor diodes required c. avoid the need for cooling d. provide a greater bandwidth

395. 24. A parametric amplifier sometimes uses a circulator to a. prevent noise feedback b. allow the antenna to be used simultaneously for transmission and reception c. separate the signal and idler frequencies d. permit more efficient pumping

396. 24. A parametric amplifier sometimes uses a circulator to a. prevent noise feedback b. allow the antenna to be used simultaneously for transmission and reception c. separate the signal and idler frequencies d. permit more efficient pumping

397. 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 figure c. reduces the pump power required d. permits satisfactory low frequency operation

398. 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 figure c. reduces the pump power required d. permits satisfactory low frequency operation

399. 26. Tunnel diode a. has a tiny hole through its center to facilitate tunneling b. is a point contact diode with a very high reverse resistance c. uses a high doping level to provide a narrow junction d. works by quantum tunneling exhibited by gallium arsenide only

400. 26. Tunnel diode a. has a tiny hole through its center to facilitate tunneling b. is a point contact diode with a very high reverse resistance c. uses a high doping level to provide a narrow junction d. works by quantum tunneling exhibited by gallium arsenide only

401. 27. A tunnel diode is loosely coupled to its cavity in order to a. increase the frequency stability b. increase the availability negative resistance c. facilitate tunning d. allow operation at the highest frequencies

402. 27. A tunnel diode is loosely coupled to its cavity in order to a. increase the frequency stability b. increase the availability negative resistance c. facilitate tunning d. allow operation at the highest frequencies

403. 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 point d. may be improved by the use of reverse bias

404. 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 point d. may be improved by the use of reverse bias

405. 29. The biggest advantage of gallium antimonide over germanium for tunnel diode use is that the former has a a. lower noise b. higher ion mobility c. larger voltage swing d. simpler fabrication process

406. 29. The biggest advantage of gallium antimonide over germanium for tunnel diode use is that the former has a a. lower noise b. higher ion mobility c. larger voltage swing d. simpler fabrication process

407. 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 junction d. electron domains forming at the junction

408. 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 junction d. electron domains forming at the junction

409. 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 mobility c. has lower noise at the highest frequencies d. is capable of handling higher power densities

410. 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 mobility c. has lower noise at the highest frequencies d. is capable of handling higher power densities

411. 32. The biggest disadvantage of IMPATT diode is its a. lower efficiency than that of the other microwave diodes b. high noise c. inability to provide pulsed operation d. lower ability handling ability

412. 32. The biggest disadvantage of IMPATT diode is its a. lower efficiency than that of the other microwave diodes b. high noise c. inability to provide pulsed operation d. lower ability handling ability

413. 33. The magnetic field is used with a ruby maser to a. provide sharp focusing for the electron beam b. increase the population inversion c. allow room temperature operation d. provide frequency adjustments

414. 33. The magnetic field is used with a ruby maser to a. provide sharp focusing for the electron beam b. increase the population inversion c. allow room temperature operation d. provide frequency adjustments

415. 34. The ruby maser has been preferred to the ammonia maser for microwave amplification, because the former has a. a much greater bandwidth b. a better frequency stability c. a low noise figure d. no need for circulator

416. 34. The ruby maser has been preferred to the ammonia maser for microwave amplification, because the former has a. a much greater bandwidth b. a better frequency stability c. a low noise figure d. no need for circulator

417. 35. Parametric amplifiers and masers a re similar to each other in that both (false) a. must have pumping b. are extremely low noise amplifiers c. must be cooled down to a few Kelvin d. generally require circulators, since the are one port devices

418. 35. Parametric amplifiers and masers a re similar to each other in that both (false) a. must have pumping b. are extremely low noise amplifiers c. must be cooled down to a few Kelvin d. generally require circulators, since the are one port devices

419. 36. Maser RF amplifier is not really suitable for a. radio astronomy b. satellite communications c. radar d. troposcatter receivers

420. 36. Maser RF amplifier is not really suitable for a. radio astronomy b. satellite communications c. radar d. troposcatter receivers

421. 37. The ruby maser laser differs from the ruby maser in that the former a. does not require pumping b. needs no resonator c. is an oscillator d. produces much lower powers

422. 37. The ruby maser laser differs from the ruby maser in that the former a. does not require pumping b. needs no resonator c. is an oscillator d. produces much lower powers

423. 38. The output from a laser is monochromatic; this means that it is a. infrared b. polarized c. narrow beam d. single frequency

424. 38. The output from a laser is monochromatic; this means that it is a. infrared b. polarized c. narrow beam d. single frequency

425. 39. For a given average power, the peak output power of a ruby laser may be increased by a. using cooling b. using Q spoiling c. increasing the magnetic field d. dispensing the Farby-Perot resonator

426. 39. For a given average power, the peak output power of a ruby laser may be increased by a. using cooling b. using Q spoiling c. increasing the magnetic field d. dispensing the Farby-Perot resonator

427. 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

428. 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

429. 41. Indicate the false statement. The advantage of semiconductor lasers over LEDs include a. monochromatic output b. higher power output c. lower cost d. ability to be pulsed at higher rates

430. 41. Indicate the false statement. The advantage of semiconductor lasers over LEDs include a. monochromatic output b. higher power output c. lower cost d. ability to be pulsed at higher rates

431. CHAPTER 13: PULSE COMMUNICATIONS

432. 1. Indicate which of the following is not a binary code a. morse b. baudot c. CCITT-2 d. ARQ

433. 1. Indicate which of the following is not a binary code a. morse b. baudot c. CCITT-2 d. ARQ

434. 2. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is a. 2 b. Log 10 16 c. 8 d. 4

435. 2. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is a. 2 b. Log 10 16 c. 8 d. 4

436. 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 redundant c. noise would introduce too many errors d. too many pulses per letter are required

437. 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 redundant c. noise would introduce too many errors d. too many pulses per letter are required

438. 4. The Hartley law states that a. 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 essential d. only binary codes may be used

439. 4. The Hartley law states that a. 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 essential d. only binary codes may be used

440. 5. Indicate the false statement. In order to combat noise, a. the channel bandwidth may be increased b. redundancy may be used c. the transmitted power may be increased d. the signalling rate may be reduced

441. 5. Indicate the false statement. In order to combat noise, a. the channel bandwidth may be increased b. redundancy may be used c. the transmitted power may be increased d. the signalling rate may be reduced

442. 6. The most common modulation system used for telegraphy is a. frequency shift keying b. two tone modulation c. pulse code modulation d. single tone modulation

443. 6. The most common modulation system used for telegraphy is a. frequency shift keying b. two tone modulation c. pulse code modulation d. single tone modulation

444. 7. Pulse width modulation may be generated a. by differentiating pulse position modulation b. with a mono stable multivibrator c. by integrating the signal d. with free running multi vibrator

445. 7. Pulse width modulation may be generated a. by differentiating pulse position modulation b. with a mono stable multivibrator c. by integrating the signal d. with free running multi vibrator

446. 8. Indicate which of the following system is digital a. Pulse position modulation b. Pulse code modulation c. Pulse width modulation d. Pulse frequency modulation

447. 8. Indicate which of the following system is digital a. Pulse position modulation b. Pulse code modulation c. Pulse width modulation d. Pulse frequency modulation

448. 9. Quantizing noise occurs in a. time division multiplex b. frequency division multiplex c. pulse code modulation d. pulse width modulation

449. 9. Quantizing noise occurs in a. time division multiplex b. frequency division multiplex c. pulse code modulation d. pulse width modulation

450. 10. The modulation system inherently most noise resistant is a. SSB, suppressed carrier b. Frequency modulation c. Pulse position modulation d. Pulse code modulation

451. 10. The modulation system inherently most noise resistant is a. SSB, suppressed carrier b. Frequency modulation c. Pulse position modulation d. Pulse code modulation

452. 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

453. 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

454. 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

455. 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

456. 13. Indicate which of the following pulse modulation system analog. a. PCM b. Differential PCM c. PWM d. Delta

457. 13. Indicate which of the following pulse modulation system analog. a. PCM b. Differential PCM c. PWM d. Delta

458. 14. Companding is used a. to overcome quantizing noise in PCM b. in PCM transmitter, to allow amplitude limiting in the receivers c. to protect small signals in PCM from quantizing distortion d. in the PCM receivers to overcome impulse noise

459. 14. Companding is used a. to overcome quantizing noise in PCM b. in PCM transmitter, to allow amplitude limiting in the receivers c. to protect small signals in PCM from quantizing distortion d. in the PCM receivers to overcome impulse noise

460. 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 TDM d. the large bandwidths that are required for it

461. 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 TDM d. the large bandwidths that are required for it

462. CHAPTER 14: DIGITAL COMMUNICATIONS

463. 1. Digital signals a. do not provide a continuous set of values b. present values as discrete steps c. can utilized decimal or binary systems d. all of the above

464. 1. Digital signals a. do not provide a continuous set of values b. present values as discrete steps c. can utilized decimal or binary systems d. all of the above

465. 2. The event which marked the start of the modern computer age was a. design of the ENIAC computer b. development of the Hollerith code c. development of the transistor d. development of the disk drives for data storage

466. 2. The event which marked the start of the modern computer age was a. design of the ENIAC computer b. development of the Hollerith code c. development of the transistor d. development of the disk drives for data storage

467. 3. The baud rate a. is always equal to the bit transfer rate b. is equal to twice the bandwidth of an ideal channel c. is not equal to the signaling rate d. is equal to one half the bandwidth of an ideal channel

468. 3. The baud rate a. is always equal to the bit transfer rate b. is equal to twice the bandwidth of an ideal channel c. is not equal to the signaling rate d. is equal to one half the bandwidth of an ideal channel

469. 4. The Shannon Hartley Law a. refers to distortion b. defines bandwidth c. describes signalling rates d. refers to noise

470. 4. The Shannon Hartley Law a. refers to distortion b. defines bandwidth c. describes signalling rates d. refers to noise

471. 5. The code which provides parity check is a. Baudot b. ASCII c. EBCDIC d. CCITT-2

472. 5. The code which provides parity check is a. Baudot b. ASCII c. EBCDIC d. CCITT-2

473. 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 pf the signal to be retransmitted d. using parity to correct the errors in all cases

474. 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 pf the signal to be retransmitted d. using parity to correct the errors in all cases

475. 7. Full duplex operation a. requires two pairs of cables b. can transfer data in both directions at once c. requires modems at both ends of the circuit d. all of the above

476. 7. Full duplex operation a. requires two pairs of cables b. can transfer data in both directions at once c. requires modems at both ends of the circuit d. all of the above

477. 8. The RS-232 interface a. interconnects data sets and transmission circuits b. uses several different connectors c. permits custom wiring of signal lines to the connector pins as desired d. all of the above

478. 8. The RS-232 interface a. interconnects data sets and transmission circuits b. uses several different connectors c. permits custom wiring of signal lines to the connector pins as desired d. all of the above

479. 9. Switching systems a. improve the efficiency of the data transfer b. are not used in data system c. require additional lines d. are limited to small data networks

480. 9. Switching systems a. improve the efficiency of the data transfer b. are not used in data system c. require additional lines d. are limited to small data networks

481. 10. The data transmission rate of a modem is measured in a. Bytes per second b. Baud rate c. Bits per second d. Megahertz

482. 10. The data transmission rate of a modem is measured in a. Bytes per second b. Baud rate c. Bits per second d. Megahertz

483. CHAPTER 15: BROADBAND COMMUNICATIONS SYSTEM

484. 1. Broadband long distance communications are originally made possible by the advent of a. telegraph cables b. repeater amplifiers c. HF radio d. Geostationary satellites

485. 1. Broadband long distance communications are originally made possible by the advent of a. telegraph cables b. repeater amplifiers c. HF radio d. Geostationary satellites

486. 2. Scheme in which several channels are interleaved and then transmitted together is known as a. Frequency division multiplex b. Time division multiplex c. A group d. A super group

487. 2. Scheme in which several channels are interleaved and then transmitted together is known as a. Frequency division multiplex b. Time division multiplex c. A group d. A super group

488. 3. Basic group B a. occupies the frequency range from 60 to 108 KHz b. consist of erect channels only c. is formed at the group translating equipment d. consist of five super group

489. 3. Basic group B a. occupies the frequency range from 60 to 108 KHz b. consist of erect channels only c. is formed at the group translating equipment d. consist of five super group

490. 4. Time division multiplex a. can be used with PCM only b. combines five groups into a super group c. stacks 24 channels in adjacent frequency slots d. interleaves pulses belonging to different transmissions

491. 4. Time division multiplex a. can be used with PCM only b. combines five groups into a super group c. stacks 24 channels in adjacent frequency slots d. interleaves pulses belonging to different transmissions

492. 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 system c. the number of coaxial cables in the tube d. the separation of the equalizers

493. 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 system c. the number of coaxial cables in the tube d. the separation of the equalizers

494. 6. Super group pilot is a. applied at each multiplexing bay b. used to regulate the gain of individual repeaters c. applied at each adjustable equalizer d. fed in at a GTE

495. 6. Super group pilot is a. applied at each multiplexing bay b. used to regulate the gain of individual repeaters c. applied at each adjustable equalizer d. fed in at a GTE

496. 7. Microwave link repeaters are typically 50km apart a. because of atmospheric attenuation b. because of output power limitations c. because of earths curvature d. to ensure that the applied dc voltage is not excessive

497. 7. Microwave link repeaters are typically 50km apart a. because of atmospheric attenuation b. because of output power limitations c. because of earths curvature d. to ensure that the applied dc voltage is not excessive

498. 8. Microwave links are generally preferred to coaxial cable for television transmission because a. the have less overall phase distortion b. they are cheaper c. of their greater bandwidths d. of their relatively immunity to impulse noise

499. 8. Microwave links are generally preferred to coaxial cable for television transmission because a. the have less overall phase distortion b. they are cheaper c. of their greater bandwidths d. of their relatively immunity to impulse noise

500. 9. Armored submarine cable is used a. to protect the cable at great depths b. to prevent inadvertent ploughing in of the cable c. for the shallow shore ends of the cable d. to prevent insulation breakdown from the high feeds voltages

501. 9. Armored submarine cable is used a. to protect the cable at great depths b. to prevent inadvertent ploughing in of the cable c. for the shallow shore ends of the cable d. to prevent insulation breakdown from the high feeds voltages

502. 10. Submarine cable repeater contains among other equipments a. a dc power supply and regulator b. filters for two directions of transmission c. multiplexing and demultiplexing equipment d. pilot inject and pilot extract equipment

503. 10. Submarine cable repeater contains among other equipments a. a dc power supply and regulator b. filters for two directions of transmission c. multiplexing and demultiplexing equipment d. pilot inject and pilot extract equipment

504. 11. Geostationary satellite a. 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

505. 11. Geostationary satellite a. 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

506. 12. Indicate the correct statement regarding satellite communications. a. if two earth stations do not face a common satellite the should be communicate via double satellite hop b. satellite are allocated so that it is impossible for to earths 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.

507. 12. Indicate the correct statement regarding satellite communications. a. if two earth stations do not face a common satellite the should be communicate via double satellite hop b. satellite are allocated so that it is impossible for to earths 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.

508. 13. Satellite used for inter continental communications are known as a. Comsat b. Domsat c. Marisat d. Intelsat

509. 13. Satellite used for inter continental communications are known as a. Comsat b. Domsat c. Marisat d. Intelsat

510. 14. Identical telephone number in different parts of a country are distinguished by their a. language digits b. access digits c. area codes d. central office codes

511. 14. Identical telephone number in different parts of a country are distinguished by their a. language digits b. access digits c. area codes d. central office codes

512. 15. Telephone traffic is measured a. with echo cancellers b. by their relative congestions c. in terms of the grade of services d. in erlangs

513. 15. Telephone traffic is measured a. with echo cancellers b. by their relative congestions c. in terms of the grade of services d. in erlangs

514. 16. In order to separate channels in a TDM receiver, it is necessary to use a. AND gates b. Bandpass filter c. Differentiation d. Integration

515. 16. In order to separate channels in a TDM receiver, it is necessary to use a. AND gates b. Bandpass filter c. Differentiation d. Integration

516. 17. To separate channels in a FDM receiver, it is necessary to use a. AND gates b. Bandpass filter c. Differentiation d. Integration

517. 17. To separate channels in a FDM receiver, it is necessary to use a. AND gates b. Bandpass filter c. Differentiation d. Integration

518. 18. Higher order TDM levels are obtained by a. dividing pulse widths b. using the a-law c. using the u-law d. forming supermastergroups

519. 18. Higher order TDM levels are obtained by a. dividing pulse widths b. using the a-law c. using the u-law d. forming supermastergroups

520. 19. Losses in optical fiber can be caused by (false) a. impurities b. microbending c. attenuation in the glass d. stepped index operation

521. 19. Losses in optical fiber can be caused by (false) a. impurities b. microbending c. attenuation in the glass d. stepped index operation

522. 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

523. 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

524. 21. Indicate which of the following is not a submarine cable a. TAT-7 b. INTELSAT V c. ATLANTIS d. CANTAT 2

525. 21. Indicate which of the following is not a submarine cable a. TAT-7 b. INTELSAT V c. ATLANTIS d. CANTAT 2

526. 22. Indicate which of the following is an American Domsat system a. INTELSAT b. COMSAT c. TELSAT d. INMARSAT

527. 22. Indicate which of the following is an American Domsat system a. INTELSAT b. COMSAT c. TELSAT d. INMARSAT

528. CHAPTER 16: RADAR SYSTEM

529. 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. 2 b. 4 c. 8 d. 16

530. 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. 2 b. 4 c. 8 d. 16

531. 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)^1/2 b. 2 c. 4 d. 8

532. 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)^1/2 b. 2 c. 4 d. 8

533. 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 range b. good target discrimination c. difficult target acquisition d. increased capture area

534. 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 range b. good target discrimination c. difficult target acquisition d. increased capture area

535. 4. The radar cross section to a target (false) a. depends on the frequency used b. may be reduced by special coating of the target c. depends on the aspect of a target, if this is nonspherical d. is equal to the actual cross sectional area for small targets

536. 4. The radar cross section to a target (false) a. depends on the frequency used b. may be reduced by special coating of the target c. depends on the aspect of a target, if this is nonspherical d. is equal to the actual cross sectional area for small targets

537. 5. Flat topped rectangular pulses must be transmitted in radar to (false) a. allow good minimum range b. make the returned echoes easier to distinguish from noise c. prevent frequency changes in the magnetron d. allow accurate range measurements

538. 5. Flat topped rectangular pulses must be transmitted in radar to (false) a. allow good minimum range b. make the returned echoes easier to distinguish from noise c. prevent frequency changes in the magnetron d. allow accurate range measurements

539. 6. High PRF will (false) a. make the returned echoes easier to distinguish from noise b. make target tracing easier with conical scanning c. increase maximum range d. have no effect on the range resolution

540. 6. High PRF will (false) a. make the returned echoes easier to distinguish from noise b. make target tracing easier with conical scanning c. increase maximum range d. have no effect on the range resolution

541. 7. The IF bandwidth of a radar receiver is inversely proportional to the a. pulse width b. pulse repetition frequency c. pulse interval d. square root of the peak transmitted power

542. 7. The IF bandwidth of a radar receiver is inversely proportional to the a. pulse width b. pulse repetition frequency c. pulse interval d. square root of the peak transmitted power

543. 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 overloaded c. it will not be received d. the target will appear closer than it really is

544. 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 overloaded c. it will not be received d. the target will appear closer than it really is

545. 9. After a target has been acquired, the best scanning system for tracking is a. nodding b. spiral c. conical d. helical

546. 9. After a target has been acquired, the best scanning system for tracking is a. nodding b. spiral c. conical d. helical

547. 10. If the target cross section is changing, the best system for accurate tracking is a. lobe switching b. sequential lobbing c. conical scanning d. mono pulse

548. 10. If the target cross section is changing, the best system for accurate tracking is a. lobe switching b. sequential lobbing c. conical scanning d. mono pulse

549. 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 range c. a transponder is required at the target d. it does not give the target position

550. 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 range c. a transponder is required at the target d. it does not give the target position

551. 12. A scope displays a. the target position and range b. the target range, but not position c. the target position, but not the range d. neither range nor position, but only velocity

552. 12. A scope displays a. the target position and range b. the target range, but not position c. the target position, but not the range d. neither range nor position, but only velocity

553. 13. The Doppler effect is used in (false) a. moving target plotting on the PPI b. the MTI system c. FM radar d. CW radar

554. 13. The Doppler effect is used in (false) a. moving target plotting on the PPI b. the MTI system c. FM radar d. CW radar

555. 14. The coho in MTI radar operates at the a. intermediate frequency b. transmitted frequency c. received frequency d. pulse repetition frequency

556. 14. The coho in MTI radar operates at the a. intermediate frequency b. transmitted frequency c. received frequency d. pulse repetition frequency

557. 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

558. 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

559. 16. A solution to the “blind speed” problem is to a. change the Doppler frequency b. Vary the PRF c. Use monopulse d. Use MTI

560. 16. A solution to the “blind speed” problem is to a. change the Doppler frequency b. Vary the PRF c. Use monopulse d. Use MTI

561. 17. Indicate which one of the following applications are advantages of radar beacons is false: a. target identification b. navigation c. very significant extension of the maximum range d. more accurate tracking of enemy targets

562. 17. Indicate which one of the following applications are advantages of radar beacons is false: a. target identification b. navigation c. very significant extension of the maximum range d. more accurate tracking of enemy targets

563. 18. Compared with other types of radar, phased array radar has the following advantages (false) a. very fast scanning b. ability to tract and scan simultaneously c. circuit simplicity d. ability to track may targets simultaneously

564. 18. Compared with other types of radar, phased array radar has the following advantages (false) a. very fast scanning b. ability to tract and scan simultaneously c. circuit simplicity d. ability to track may targets simultaneously

565. CHAPTER 17: TELEVISION FUNDAMENTALS

566. 1. The number of lines per field in the United State TV system is a. 262 ½ b. 525 c. 30 d. 60

567. 1. The number of lines per field in the United State TV system is a. 262 ½ b. 525 c. 30 d. 60

568. 2. The number of frames per second in the US TV system is a. 60 b. 262 ½ c. 4.5 d. 30

569. 2. The number of frames per second in the US TV system is a. 60 b. 262 ½ c. 4.5 d. 30

570. 3. The number of lines per second in the US TV system is a. 31500 b. 15750 c. 262 ½ d. 525

571. 3. The number of lines per second in the US TV system is a. 31500 b. 15750 c. 262 ½ d. 525

572. 4. The channel width in the US TV system, in MHz is a. 41.25 b. 6 c. 4.5 d. 3.58

573. 4. The channel width in the US TV system, in MHz is a. 41.25 b. 6 c. 4.5 d. 3.58

574. 5. Interlacing is used in television to a. produce the illusion of motion b. 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

575. 5. Interlacing is used in television to a. produce the illusion of motion b. 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

576. 6. The signals sent by the TV transmitter to ensure correct scanning in the receiver are called a. sync b. chroma c. luminance d. video

577. 6. The signals sent by the TV transmitter to ensure correct scanning in the receiver are called a. sync b. chroma c. luminance d. video

578. 7. In the US color television system, the intercarrier frequency, in MHz a. 3.58 b. 3.579545 c. 4.5 d. 45.75

579. 7. In the US color television system, the intercarrier frequency, in MHz a. 3.58 b. 3.579545 c. 4.5 d. 45.75

580. 8. Indicate which voltages are not found in the output of a normal monochrome receiver video detector a. sync b. video c. sweep d. sound

581. 8. Indicate which voltages are not found in the output of a normal monochrome receiver video detector a. sync b. video c. sweep d. sound

582. 9. The carrier transmitted 1.25MHz above the bottom frequency in a US TV system channel is the a. sound carrier b. chroma carrier c. intercarrier d. picture carrier

583. 9. The carrier transmitted 1.25MHz above the bottom frequency in a US TV system channel is the a. sound carrier b. chroma carrier c. intercarrier d. picture carrier

584. 10. In television 4:3 represents the a. interlace ratio b. maximum horizontal deflection c. aspect ratio d. ratio of the two diagonals

585. 10. In television 4:3 represents the a. interlace ratio b. maximum horizontal deflection c. aspect ratio d. ratio of the two diagonals

586. 11. Equalizing pulses in TV are sent during a. horizontal blanking b. vertical blanking c. the serrations d. the horizontal retrace

587. 11. Equalizing pulses in TV are sent during a. horizontal blanking b. vertical blanking c. the serrations d. the horizontal retrace

588. 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 interlace b. purely an accident c. to ensure that line and frame frequencies can be obtained from the same original source d. done to minimize interference with the chroma subcarriers

589. 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 interlace b. purely an accident c. to ensure that line and frame frequencies can be obtained from the same original source d. done to minimize interference with the chroma subcarriers

590. 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 synchronization c. help horizontal synchronization d. simplify the generation of vertical sync pulse

591. 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 synchronization c. help horizontal synchronization d. simplify the generation of vertical sync pulse

592. 14. The width of the vertical pulse in US TV system is a. 21H b. 3H c. H d. 0.5H

593. 14. The width of the vertical pulse in US TV system is a. 21H b. 3H c. H d. 0.5H

594. 15. Indicate which of the following frequencies will not be found in the output of a normal TV receiver tuner: a. 4.5 MHz b. 41.25 MHz c. 45.75 MHz d. 42.17 MHz

595. 15. Indicate which of the following frequencies will not be found in the output of a normal TV receiver tuner: a. 4.5 MHz b. 41.25 MHz c. 45.75 MHz d. 42.17 MHz

596. 16. The video voltage applied to the picture tube of a television receiver is fed in a. between grid and ground b. to the yoke c. to the anode d. between the grid and cathode

597. 16. The video voltage applied to the picture tube of a television receiver is fed in a. between grid and ground b. to the yoke c. to the anode d. between the grid and cathode

598. 17. The circuit that separates the sync pulse from the composite video waveform is a. the keyed AGC amplifier b. a clipper c. an integrator d. a differentiator

599. 17. The circuit that separates the sync pulse from the composite video waveform is a. the keyed AGC amplifier b. a clipper c. an integrator d. a differentiator

600. 18. The output of the vertical amplifier, applied to the yoke in the TV receiver, consist of a. direct current b. amplified vertical sync pulses c. saw tooth voltage d. a saw tooth current

601. 18. The output of the vertical amplifier, applied to the yoke in the TV receiver, consist of a. direct current b. amplified vertical sync pulses c. saw tooth voltage d. a saw tooth current

602. 19. The HV anode supply for the picture tube for a TV receiver is generated in the a. main transformer b. vertical output stage c. horizontal output stage d. horizontal deflection stage

603. 19. The HV anode supply for the picture tube for a TV receiver is generated in the a. main transformer b. vertical output stage c. horizontal output stage d. horizontal deflection stage

604. 20. Another name for the horizontal retrace in a TV receiver is the a. ringin b. burst c. damper d. flyback

605. 20. Another name for the horizontal retrace in a TV receiver is the a. ringin b. burst c. damper d. flyback

606. 21. Indicate which of the following signal is not transmitted in color TV: a. Y b. Q c. R d. I

607. 21. Indicate which of the following signal is not transmitted in color TV: a. Y b. Q c. R d. I

608. 22. The Shadow mask in a color picture tube is used to a. reduce x-ray emission b. ensure that each beam hits only its own dots c. increase screen brightness d. provide degaussing for the screen

609. 22. The Shadow mask in a color picture tube is used to a. reduce x-ray emission b. ensure that each beam hits only its own dots c. increase screen brightness d. provide degaussing for the screen

610. 23. In a TV receiver the color killer a. cuts off the chroma stages during monochrome reception b. ensure that no color is transmitted to monochrome receiver c. prevents color over loading d. makes sure that the color burst is not mistaken for sync pulse, by cutting off reception during the back porch

611. 23. In a TV receiver the color killer a. cuts off the chroma stages during monochrome reception b. ensure that no color is transmitted to monochrome receiver c. prevents color over loading d. makes sure that the color burst is not mistaken for sync pulse, by cutting off reception during the back porch

612. CHAPTER 18: INTRODUCTION TO FIBER OPTIC TECHNOLOGY

613. 1. What is the frequency limit of copper wire? a. Approximately 0.5 MHz b. Approximately 1.0 MHz c. Approximately 40 GHz d. None of the above

614. 1. What is the frequency limit of copper wire? a. Approximately 0.5 MHz b. Approximately 1.0 MHz c. Approximately 40 GHz d. None of the above

615. 2. Approximately what is the frequency limit of the optical fiber? a. 20 GHz b. 1 MHz c. 100 MHz d. 40 MHz

616. 2. Approximately what is the frequency limit of the optical fiber? a. 20 GHz (no given answer) b. 1 MHz c. 100 MHz d. 40 MHz

617. 3. A single fiber can handle as many voice channels as a. A pair of copper conductors b. A 1500-pair cable c. A 500-pair cable d. A 1000- pair cable

618. 3. A single fiber can handle as many voice channels as a. A pair of copper conductors b. A 1500-pair cable c. A 500-pair cable d. A 1000- pair cable

619. 4. An incident ray can be defined as a. A light ray reflected from a flat surface b. A light ray directed towards a surface c. A diffused light ray d. A light ray that happens periodically

620. 4. An incident ray can be defined as a. A light ray reflected from a flat surface b. A light ray directed towards a surface c. A diffused light ray d. A light ray that happens periodically

621. 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

622. 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

623. 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

624. 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

625. 7. The term critical angle describes a. The point at which light is refracted b. The point at which light becomes invisible c. 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

626. 7. The term critical angle describes a. The point at which light is refracted b. The point at which light becomes invisible c. 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

627. 8. The cladding which surrounds the fiber core a. Is used to reduce optical interference b. Is used to protect the fiber c. Acts to help guide the light in the core d. Ensures that the refractive index remains constant

628. 8. The cladding which surrounds the fiber core a. Is used to reduce optical interference b. Is used to protect the fiber c. Acts to help guide the light in the core d. Ensures that the refractive index remains constant

629. 9. The reflective index number is a. 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

630. 9. The reflective index number is a. 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

631. 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

632. 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

633. 11. The higher the index number a. The higher the speed of light b. The lower the speed of light c. Has no effect on the speed of light d. The shorter the wavelength propagation

634. 11. The higher the index number a. The higher the speed of light b. The lower the speed of light c. Has no effect on the speed of light d. The shorter the wavelength propagation

635. 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

636. 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

637. 13. As light is coupled in a multipoint reflective device, the power is reduce by a. 1.5 dB b. 0.1 dB c. 0.5 dB d. 0.001 dB

638. 13. As light is coupled in a multipoint reflective device, the power is reduce by a. 1.5 dB b. 0.1 dB c. 0.5 dB d. 0.001 dB

639. 14. When connector losses, splice losses, and coupler losses are added, what is the final limiting factor? a. Source power b. Fiber attenuation c. Connector and splice losses d. Detector sensitivity

640. 14. When connector losses, splice losses, and coupler losses are added, what is the final limiting factor? a. Source power b. Fiber attenuation c. Connector and splice losses d. Detector sensitivity

641. 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

642. 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

643. 16. Loss comparisons between fusion splices and mechanical splices are a. 1:10 b. 10:1 c. 20:1 d. 1:20

644. 16. Loss comparisons between fusion splices and mechanical splices are a. 1:10 b. 10:1 c. 20:1 d. 1:20

645. 17. The mechanical splice is best suited for a. Quicker installation under ideal conditions b. Minimum attenuation losses c. Field service conditions d. Situations in which cost of equipment is not a factor

646. 17. The mechanical splice is best suited for a. Quicker installation under ideal conditions b. Minimum attenuation losses c. Field service conditions d. Situations in which cost of equipment is not a factor

647. 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

648. 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

649. 19. Which of the following cables will have the highest launch power capability a. 50/125/0.2 b. 85/125/0.275 c. 62.5/125/0.275 d. 100/140/0.3

650. 19. Which of the following cables will have the highest launch power capability a. 50/125/0.2 b. 85/125/0.275 c. 62.5/125/0.275 d. 100/140/0.3

651. 20. The term power budgeting refers to a. The cost of cables, connectors, equipment, and installation b. The loss of power due to defective components c. The total power available minus the attenuation losses d. The comparative costs of fiber and copper installations

652. 20. The term power budgeting refers to a. The cost of cables, connectors, equipment, and installation b. The loss of power due to defective components c. The total power available minus the attenuation losses d. The comparative costs of fiber and copper installations

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