36. A PAM signal can be demodulated using
A. a low pass filter
B. a band pass filter
C. a high pass filter
D. none of the above

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37. In time-division-multiplexing, each multiplexed signal occupies
A. the entire transmission bandwidth
B. a fraction of the transmission bandwidth
C. a bandwidth equal to the bandwidth of each input signal
D. none of above

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38. The signal propagation time between two ground stations in a synchronous satellite link is about millisecond.
A.50
B.135
C.270
D.300

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39. Pulse modulation is used in
A. Radio navigation
B. Automatic landing equipments
C.Data communications
D. All of the above

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40. In pulse transmitter theratio of time on to time off is called
A. efficiency
B. duty cycle
C. base
D. bandwidth

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41. Quantization noise occurs in
A. PCM
B. TDM
C.FDM
D. PWD

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42. Which of the following modulating system is inherently most noise-resistant?
A. PCM
B. PPM
C. FM
D.DSB

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