57. Pulse communication system that is inherently highly immune to noise is
A. PAM
B. PWM
C. PPM
D. PCM

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58. If a time function contains no frequency components higher than W Hz, then the time functions can be completely determined by specifying its ordinates at1 a series of points spaced every sec.2W or less
A. True
B. False
C.
D.

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59. In order to reduce quantizing noise, one must
A. increase the number of standard amplitudes level.s
B. send pulse whose sides are more nearly vergical
C. use an R.F. amplifier in the receiver
D. increase the number of samples per second

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60. In a DM system, the granular (idling) noise occurs when the modulating signal
A. increase rapidly
B. remains constant
C. decreases rapidly
D. the nature of the modulating signal has nothing to do with this noise

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61. The biggest disadvantage of PCM is
A. its inability to handle analog signals
B. the high error rate which its quantizing noise reduces
C. its incompatibility with TDM
D. the large bandwidth that are required. for it

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62. Quantization noise is produced in
A. all pulse modulation system
B. PCM
C. all modulation system
D. None of the above

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63. In PCM system, output S/N increases
A. linearly with width
B. exponentially with bandwidth
C. inversely with bandwidth
D. None of the above

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