Digital Communications Multiple Choice Questions 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
Answer: C
Clarification: 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
Answer: D
Clarification: 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
Answer: A
Clarification: Wired channels are lossy channels.
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
Answer: A
Clarification: 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
Answer: A
Clarification: Interpolator corrects the sampling time problem using discrete time processing.
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
Answer: D
Clarification: 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
Answer: D
Clarification: Air, water and copper cable can be used as transmission media in low frequency band communication.
8. Transmission media used for medium frequency band are
A. Coaxial cable
B. Copper cable
C. Optical fiber
D. All of the mentioned
Answer: B
Clarification: 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
Answer: A
Clarification: Matched filter technique is a demodulation process used to increase SNR.
10. Matched filter can also be used as least squares estimator.
A. True
B. False
Answer: A
Clarification: 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
Answer: D
Clarification: 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