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ECE Objective Questions { Analog Communication System }



36.  The power content of a sideband of an AM wave with 60% modulation is 720W. If modulation is increased to 80%,sideband power will become watt.
A.540
B.960
C.1280
D.405

37. The total power content of an AM wave is 600 W. If each sideband contains 100W, percentage modulation is
A.100
B.80
C.50
D.16.6

38. A single-sideband (SSB) signal contains 3 kW. The power content of the carrier is kW.
A.2
B.1
C.3
D.0

39. The difference between phase and frequency modulation
A. is purely theoretical because they are the same in practice
B. is too great to make the two systems compatible
C. lies in the poorer audio responses of phase modulation index
D. lies in the different definition of the modulation index

40. A 100 MHz carrier wave is frequency modulated by a 5-kHz sine wave. If resultant FM signal has a frequency deviation of 50 kHz, its carrier swing is kHz.
A.100
B.10
C.110
D.55

41. In frequency modulation
A. the frequency of carrier varies according to the amplitude of the modulating signal
B. the frequency of carrier varies according to the frequency of the modulating signal
C. the amplitude of the carrier varies according to the frequency of the modulating signal
D. all the above

42. An FM signal has a carrier swing of 100 kHz and a modulating signal of 10 kHz. Its modulation index is
A.10
B.5
C.20
D.0.1

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