Digital Communications Questions and Answers – Digital Communication System – 1

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
View Answer

Answer: c
Explanation: The main features of a receiver which increases its complexity are synchronization of carrier, phase, and timing and multiple parallel receiver chain.

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
View Answer

Answer: d
Explanation: Some of the conditions which must be satisfied in a digital communication system are high data rate, high fidelity, low bandwidth, low transmit power and low transmitter and receiver complexity.

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

Answer: a
Explanation: Wired channels are lossy channels.
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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
View Answer

Answer: a
Explanation: The equivalent temperature is the function of the receiver design and it must be always kept low.

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

Answer: a
Explanation: Interpolator corrects the sampling time problem using discrete time processing.
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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
View Answer

Answer: d
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.

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

Answer: d
Explanation: Air, water and copper cable can be used as transmission media in low frequency band communication.
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8. Transmission media used for medium frequency band are
a) Coaxial cable
b) Copper cable
c) Optical fiber
d) All of the mentioned
View Answer

Answer: b
Explanation: For medium frequency band communication air and copper cable can only be used as a transmission medium.

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

Answer: a
Explanation: Matched filter technique is a demodulation process used to increase SNR.
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10. Matched filter can also be used as least squares estimator.
a) True
b) False
View Answer

Answer: a
Explanation: A matched filter can also be used as a least squares estimator.

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

Answer: d
Explanation: Digital communication system can handle signals that are analog or those that are already digital. It can also handle 1D and 2D signals.

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

Answer: c
Explanation: Information source comes from a higher networking layer. It can be continuous or packetized.

Sanfoundry Global Education & Learning Series – Digital Communications.

To practice all areas of Digital Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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