43. Which of the following pulse modulating system is analog?
A. PCM
B. PWM
C. Both (a) and (b) above
D. None of the above
44. For transmission of normal speech signal, the PCM channel needs a bandwidth of
A. 64 kHz
B. 8 kHz
C. 4 kHz
D. 2 kHz
45. Which of the following system is digital?
A. PPM
B.PCM
C. PFM
D. PWM
46. In sampling theorem the Nyquist interval is given by
A. T = ?fm
B. T = It
C. T =
D. T = ?Tcf
47. Which of the following statement is true?
A. Pulse modulation has low power efficiency and narrow bandwidth
B. The PAM system has the best signal to noise ratio
C. Blocked-grid keying is similar to frequency-shift keying
D. None of the above
48. Which one of the following communication system is digital?
A. FM
B. AM
C.PCM
D. PAM
49. Quantizing noise occurs in
A. time-division-multiplexing
B. PCM
C. PPM
D. frequency-division-multiplexing
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