Digital Communication System MCQs

Question 1

In sampling theorem the Nyquist interval is given by

Accepted Answer

T = It

Answer

T = ?fm

Answer

T =

Answer

T = ?Tcf

Question 2

Which of the following statement is true?

Accepted Answer

Blocked-grid keying is similar to frequency-shift keying

Answer

Pulse modulation has low power efficiency and narrow bandwidth

Answer

The PAM system has the best signal to noise ratio

Answer

None of the above

Question 3

Which one of the following communication system is digital?

Accepted Answer

PCM

Answer

FM

Answer

AM

Answer

PAM

Question 4

Quantizing noise occurs in

Accepted Answer

PCM

Answer

time-division-multiplexing

Answer

PPM

Answer

frequency-division-multiplexing

Question 5

The use of non-uniform quantization leads to

Accepted Answer

increase in maximum SNR

Answer

reduction in transmission bandwidth

Answer

increase in SNR for signal levels

Answer

simplification of quantization process.

Question 6

In pulse modulation, the number of samples required to ensure no loss of information is given by

Accepted Answer

Nyquist theorem

Answer

Parsevals theorem

Answer

Fourier transform

Answer

None of the above

Question 7

Pulse amplitude modulation is a process whereby

Accepted Answer

the height of a pulse is made proportional to the sampled value

Answer

the position ofthe pulse is changed as a function of the sampled value

Answer

the width of the pulse is varied as a function of time

Answer

None of the above

Question 8

Which of the following is restriction imposed on the reconstruction of a sampled signal?

Accepted Answer

The sampling rate must be in the form of impulses

Answer

Impulses must be passed through a high pass filter

Answer

Impulses must be passed through a band pass filter

Answer

None of the above

Question 9

Pulse width of modulation is a process whereby

Accepted Answer

the width of a pulse is varicd as a function of the sampled value

Answer

the position of a pulse is changed as a function of the sampled value

Answer

the sampled value is first coded and then transmitted

Answer

None of the above