Digital Communications

Digital Communication System

Question 1
Marks : +2 | -2
Pass Ratio : 100%
If operating frequency bands are higher ______ is available.
Smaller bandwidth
Larger bandwidth
Smaller & Larger bandwidth
Cannot be determined
Explanation:
Larger bandwidth is available when operating frequency bands are higher.
Question 2
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 3
Marks : +2 | -2
Pass Ratio : 100%
Which corrects the sampling time problem in a digital system?
Interpolator
Decimator
Equalizer
Filter
Explanation:
Interpolator corrects the sampling time problem using discrete time processing.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What are the main features of a transmitter?
Higher clock speed
Linear power amplifier
Directional antennas
All of the mentioned
Explanation:
Some of the main features which make the transmitter complex are higher clock speed, higher transmit power, directional antennas and need for a linear amplifier.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Matched filter technique is used to
Increase SNR
Decrease SNR
SNR is not affected
None of the mentioned
Explanation:
Matched filter technique is a demodulation process used to increase SNR.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Matched filter can also be used as least squares estimator.
True
False
Explanation:
A matched filter can also be used as a least squares estimator.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Ground wave communication occurs in
Low frequency band
Medium frequency band
Low & Medium frequency band
None of the mentioned
Explanation:
Ground wave communication can take place in both low frequency and medium frequency bands.
Question 8
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 9
Marks : +2 | -2
Pass Ratio : 100%
Transmission media used for medium frequency band are
Coaxial cable
Copper cable
Optical fiber
All of the mentioned
Explanation:
For medium frequency band communication air and copper cable can only be used as a transmission medium.
Question 10
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.