Digital Communication System

Digital Communications Systems

This set of Digital Communications Multiple Choice Questions & Answers (MCQs) focuses on “Digital communication system”.

1. What are the main features of a receiver?
a) Synchronization
b) Multiple parallel receiver chain
c) Synchronization & Multiple parallel receiver chain
d) None of the mentioned

2. What conditions must be fulfilled in a good digital communication system?
a) High data rate
b) High fidelity
c) Low transmit power
d) All of the mentioned

3. Wired channels are
a) Lossy
b) Lossless
c) Lossy & Lossless
d) None of the mentioned

4. The equivalent temperature in a receiver design must be kept
a) Low
b) High
c) Does not affect the receiver
d) None of the mentioned

5. Which corrects the sampling time problem in a digital system?
a) Interpolator
b) Decimator
c) Equalizer
d) Filter

6. What are the main features of a transmitter?
a) Higher clock speed
b) Linear power amplifier
c) Directional antennas
d) All of the mentioned

7. Transmission media used in low frequency band are
a) Air
b) Water
c) Copper cable
d) All of the mentioned

8. Transmission media used for medium frequency band are
a) Coaxial cable
b) Copper cable
c) Optical fiber
d) All of the mentioned

9. Matched filter technique is used to
a) Increase SNR
b) Decrease SNR
c) SNR is not affected
d) None of the mentioned

10. Matched filter can also be used as least squares estimator.
a) True
b) False

11. Digital communication system can handle
a) Analog signals
b) 1D signals
c) 2D signals
d) All of the mentioned

12. The information source of a digital communication system can be
a) Packetized
b) Continuous
c) Packetized & Continuous
d) None of the mentioned

13. Which are the common transmission media used in digital communication system?
a) Coaxial cable
b) Twisted copper cable
c) Radio frequency bands
d) All of the mentioned

14. The basic transmission-reception system is a ______ system.
a) Two block system
b) Three block system
c) Four block system
d) None of the mentioned

15. Modulation channel consists of
a) Amplifier
b) Signal processing units
c) Amplifier & Signal processing units
d) None of the mentioned

16. Modulation channel does not accept an analog input signal.
a) True
b) False

17. If operating frequency bands are higher ______ is available.
a) Smaller bandwidth
b) Larger bandwidth
c) Smaller & Larger bandwidth
d) Cannot be determined

18. Ground wave communication occurs in
a) Low frequency band
b) Medium frequency band
c) Low & Medium frequency band
d) None of the mentioned

19. Sampling theorem is used for converting
a) Continuous time signal to discrete
b) Discrete to continuous time signal
c) Continuous time signal to discrete & vice versa
d) None of the mentioned

20. A signal can be recovered from its sample by using
a) Low pass filter
b) High pass filter
c) Band pass filter
d) Band stop filter

21. Which is practically realizable?
a) A train of pulses
b) Impulse train
c) All of the mentioned
d) None of the mentioned

22. In flat top sampling scheme, ______ is kept constant after sampling.
a) Amplitude
b) Phase
c) Frequency
d) Time period

23. Loop filter is a ______ used to reduce noise.
a) Low pass filter
b) High pass filter
c) Band pass filter
d) Band reject filter

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