modulation and demodulation MCQs – Page 2

Practise focused modulation and demodulation questions with marked answers for exam preparation and subject revision.

modulation and demodulation Mcqs

21. A 100 V carrier is made to vary between 160 V and 40 V by the signal. What is the modulation factor ?
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A. 3

B. None of the above

C. 6

D. 5

22. A 50 kW carrier is to be amplitude modulated to a level of 85%. What is the carrier power after modulation ?
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A. 5 kW

B. 8 kW

C. 25 kW

D. 50 kW

23. Most of the amplification in a superhetrodyne receiver occurs at ______________stage?
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A. Detector

B. IF

C. Audio amplifier

D. RF amplifier

24. In a radio receiver, noise is generally developed at _______________?
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A. Audio stage

B. IF stage

C. RF stage

D. Receiving antenna

25. The letters AVC stand for ________________?
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A. Audio voltage control

B. Abrupt voltage control

C. Automatic volume control

D. Automatic voltage control

26. In a TRF radio receiver, the RF and detection stages are tuned to______________?
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A. None of the above

B. IF

C. Audio frequency

D. Radio frequency

27. The function of ferrite antenna is to_________________?
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A. Reduce noise

B. Increase the Q of tuned circuit

C. Stabilise d.c. bias

D. Reduce stray capacitance

28. In an AM wave, the majority of the power is in _____________?
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A. Lower sideband

B. Upper sideband

C. None of the above

D. Carrier

29. When the modulating signal controls the frequency of the carrier, we get______________?
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A. Frequency modulation

B. Phase modulation

C. Amplitude modulation

D. May be any one of the above

30. In a transmitter ____________oscillator is used?
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A. Wien-bridge

B. Hartley

C. RC phase-shift

D. Crystal

31. In a superhetrodyne receiver, the difference frequency is chosen as the IF rather than the sum frequency because _________________?
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A. None of the above

B. Only the difference frequency can be modulated

C. The difference frequency is closer to oscillator frequency

D. Lower frequencies are easier to amplify

32. A high Q tuned circuit will permit an amplifier to have high __________________?
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A. Fidelity

B. Sensitivity

C. Frequency range

D. Selectivity

33. Demodulation is done in ________________?
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A. Transmitting antenna

B. Transmitter

C. Radio receiver

D. Receiving antenna

34. The IF is 455 kHz. If the radio receiver is tuned to 855 kHz, the local oscillator frequency is _______________?
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A. 1310 kHz

B. 455 kHz

C. 1520 kHz

D. 1500 kHz

35. In amplitude modulation, the _____________of carrier is varied according to the strength of the signal?
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A. None of the above

B. Amplitude

C. Frequency

D. Phase

36. Over modulation results in ______________?
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A. None of the above

B. Weakening of the signal

C. Distortion

D. Excessive carrier power

37. At 100% modulation, the power in each sideband is _____________ of that of carrier?
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A. 50%

B. 40%

C. 60%

D. 25%

38. In amplitude modulation, bandwidth is ____________ the audio signal frequency?
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A. Four times

B. Thrice

C. Twice

D. None of the above

39. If modulation is 100% then signal amplitude is ____________arrier amplitude?
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A. None of the above

B. Greater than

C. Less than

D. Equal to

40. In pakistan, ______________ modulation is used for radio transmission?
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A. Phase

B. Amplitude

C. Frequency

D. None of the above

Showing 21 to 40 of 42 mcqs