Digital Communications

Digital Communication System

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Modulation channel does not accept an analog input signal.
True
False
Explanation:
Modulation channel accepts analog signal as input and delivers another version of modulated signal as analog waveform.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Which are the common transmission media used in digital communication system?
Coaxial cable
Twisted copper cable
Radio frequency bands
All of the mentioned
Explanation:
Some of the commonly used physical transmission media are twisted copper cable, good quality coaxial cable and radio frequency bands.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Which is practically realizable?
A train of pulses
Impulse train
All of the mentioned
None of the mentioned
Explanation:
A train of pulses with narrow bandwidth is realizable than the impulse train.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
In flat top sampling scheme, ______ is kept constant after sampling.
Amplitude
Phase
Frequency
Time period
Explanation:
In flat top sampling scheme, the amplitude is kept constant after sampling.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Modulation channel consists of
Amplifier
Signal processing units
Amplifier & Signal processing units
None of the mentioned
Explanation:
When information is transmitted through large distance it must be amplified. Modulation channel consists of an amplifier and other signal processing units.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
What are the main features of a receiver?
Synchronization
Multiple parallel receiver chain
Synchronization & Multiple parallel receiver chain
None of the mentioned
Explanation:
The main features of a receiver which increases its complexity are synchronization of carrier, phase, and timing and multiple parallel receiver chain.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
The equivalent temperature in a receiver design must be kept
Low
High
Does not affect the receiver
None of the mentioned
Explanation:
The equivalent temperature is the function of the receiver design and it must be always kept low.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
The basic transmission-reception system is a ______ system.
Two block system
Three block system
Four block system
None of the mentioned
Explanation:
The basic transmission-reception consists of three blocks – transmitter, transmission medium, receiver.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Sampling theorem is used for converting
Continuous time signal to discrete
Discrete to continuous time signal
Continuous time signal to discrete & vice versa
None of the mentioned
Explanation:
Sampling theorem is used for converting continuous time signal to discrete type signal and vice versa.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
A signal can be recovered from its sample by using
Low pass filter
High pass filter
Band pass filter
Band stop filter
Explanation:
A signal can be recovered from its sampled version by using an ideal low pass filter.