| 1. | If the radiated power of AM transmitter is 10 KW, the power in the carrier for modulation index of 0.6 is nearly ? | |
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8.24 KW
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9.26 KW
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8.47 KW
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9.6 KW
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Report Question| 2. | If modulation index is increased to root 2 times, what would be the effective e transmitted power ? | |
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Equal to carrier power
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Half of carrier power
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2 times of carrier power
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root 2 times of carrier power
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| 3. | If a single-tone amplitude modulated signal at a modulation depth of 100% transmits a total power of 15 W. the power in the carrier component is ? | |
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5 W
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10 W
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12 W
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15 W
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| 4. | For a short wave radio link between two stations via the ionosphere, the ratio of the maximum usable frequency to the critical frequency ? | |
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Is always less than
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May be 1depending on the distance between the two stations
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Is always greater than 1
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Does not depend on the distance between the two stations
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| 5. | Radio frequency noise is valid for all of the following except ? | |
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Mixer stage
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If stage/IF
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Baseband recording system
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Preamplifier of radio receiver
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| 6. | Find the modulation index given : a. single tone modulation. b. positive RF peaks of an AM voltage rise to a maximum value of 8 V and drop to a minimum value of 4V ? | |
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1/3
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3
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1/2
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1/4
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| 7. | An AM wave is given by s(t) = 20(1+0.5 Cos cos cos 106t), the modulation index of the envelope is ? | |
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0.5
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0.58
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0.3
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0.8
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| 8. | For identical total transmitted power, the ratio of S/N for wide band FM to S/N of DSB-AM (with ) is : (given fm =15 KHz & frequency deviation = ) ? | |
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112.5
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300
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75
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450
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| 9. | A message signals given by m (t) = (1/2) Cos ( )-(1/2) sin ( ) amplitude modulated with a carrier of frequency to generate s (t) = [1+m (t)] Cos ( ). What is the power efficiency achieved by this modulation scheme ? | |
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8.33%
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11.11%
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20%
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25%
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| 10. | In which modulation system, when modulating frequency is doubled, the modulation index also becomes double ? | |
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AM
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FM
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PM
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None of the above
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