Digital Communication System MCQs

Question 1

The signal-to-noise (S/N) ratio appearing at the output of each channel in PAM is

Accepted Answer

twice the input S/N

Answer

three times the input S/N

Answer

one-and-half times the input S/N

Answer

None of the above

Question 2

A PWM signal can be generated by

Accepted Answer

differentiating the PPM signal

Answer

a monostable multi-vibrator

Answer

a astable multi-vibrator

Answer

integrating the PPM signal

Question 3

Pulse communication system that is inherently highly immune to noise is

Accepted Answer

PCM

Answer

PAM

Answer

PWM

Answer

PPM

Question 4

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

Accepted Answer

True

Answer

False

Question 5

In order to reduce quantizing noise, one must

Accepted Answer

increase the number of standard amplitudes level.s

Answer

send pulse whose sides are more nearly vergical

Answer

use an R.F. amplifier in the receiver

Answer

increase the number of samples per second

Question 6

In a DM system, the granular (idling) noise occurs when the modulating signal

Accepted Answer

remains constant

Answer

increase rapidly

Answer

decreases rapidly

Answer

the nature of the modulating signal has nothing to do with this noise

Question 7

The biggest disadvantage of PCM is

Accepted Answer

the large bandwidth that are required. for it

Answer

its inability to handle analog signals

Answer

the high error rate which its quantizing noise reduces

Answer

its incompatibility with TDM

Question 8

Quantization noise is produced in

Accepted Answer

PCM

Answer

all pulse modulation system

Answer

all modulation system

Answer

None of the above

Question 9

In PCM system, output S/N increases

Accepted Answer

exponentially with bandwidth

Answer

linearly with width

Answer

inversely with bandwidth

Answer

None of the above