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Digital Communications MCQs set-2
50 questions · Test your knowledge
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Digital Communications MCQs set-2
1
Find the 8-ary waveform for the word ‘HAPPY’.
A
4040020246
B
0440020246
C
6420200440
D
None of the mentioned
2
Find the 32-ary waveform for the word ‘HAPPY’.
A
280856
B
658082
C
288056
D
None of the mentioned
3
What are the characteristics of an ideal transmission line?
A
Different amplitude
B
No distortion
C
Time delay
D
All of the mentioned
4
The point at which the output signal power has fallen to 0.707 of its peak value is called as _____
A
3db point
B
Half power point
C
3db & Half power point
D
None of the mentioned
5
The ratio of the filter bandwidth at -60db and -6db amplitude response point is called as _____
A
Half point factor
B
Normalized factor
C
Shape factor
D
None of the mentioned
6
As the order of the filter increases, the cost ______ and complexity ______
A
Increases, increases
B
Increases, decreases
C
Decreases, increases
D
Decreases, decreases
7
Which filter has maximum flatness?
A
Chebyshev filter
B
Butter-worth filter
C
High pass filter
D
Normalized filter
8
The measure of the width of the main lobe is called as ________
A
Null to null bandwidth
B
Half power bandwidth
C
Normalized bandwidth
D
Absolute bandwidth
9
SQNR can be improved by _______ sampling rate.
A
Increasing
B
Decreasing
C
Does not depend
D
None of the mentioned
10
Which offers better SQNR?
A
Delta modulation
B
PCM
C
Delta modulation & PCM
D
None of the mentioned
11
Two functions are called as orthogonal if on integrating the product we get
A
One
B
Zero
C
Infinity
D
None of the mentioned
12
Eigen functions are not orthogonal.
A
True
B
False
C
D
13
Shot noise is produced by
A
Electrons
B
Photons
C
Electrons & Photons
D
None of the mentioned
14
Shot noise is avoidable when current is
A
Zero
B
One
C
Infinity
D
None of the mentioned
15
Which occurs due to equilibrium fluctuations?
A
Thermal noise
B
Johnson noise
C
Thermal & Johnson noise
D
None of the mentioned
16
Flicker noise is called as
A
White noise
B
Pink noise
C
Brown noise
D
None of the mentioned
17
Which has the same power spectral density?
A
White noise
B
Brown noise
C
White & Brown noise
D
None of the mentioned
18
Which noise is useful for dithering?
A
White noise
B
Pink noise
C
Brown noise
D
None of the mentioned
19
Capacity of a channel can be increased by
A
Increasing channel bandwidth
B
Increasing signal power
C
Increasing channel bandwidth &signal power
D
None of the mentioned
20
Capacity of the channel can be increased by reducing in band noise power.
A
True
B
False
C
D
21
Thermal noise is a wide sense stationary process.
A
True
B
False
C
D
22
The maximum likelihood function is
A
Positive
B
Negative
C
Any of the mentioned
D
None of the mentioned
23
Matched filtering operation includes
A
Spectral phase matching
B
Spectral amplitude matching
C
Spectral phase & amplitude matching
D
None of the mentioned
24
Matched filter is
A
Linear
B
Non linear
C
Linear & Non linear
D
None of the mentioned
25
Which consists of less ISI?
A
Nyquist filter
B
Raised cosine filter
C
Nyquist & Raised cosine filter
D
None of the mentioned
26
Digital communication is _______ to environmental changes?
A
Less sensitive
B
More sensitive
C
Does not depend
D
None of the mentioned
27
Advantages of digital communication are
A
Easy multiplexing
B
Easy processing
C
Reliable
D
All of the mentioned
28
What is necessary for digital communication?
A
Precision timing
B
Frame synchronization
C
Character synchronization
D
All of the mentioned
29
What are the disadvantages of digital communication?
A
Needs more bandwidth
B
Is more complex
C
Needs more bandwidth & Is more complex
D
None of the mentioned
30
Examples of digital communication are
A
ISDN
B
Modems
C
Classical telephony
D
All of the mentioned
31
Which system uses digital transmission?
A
ISDN
B
LANs
C
ISDN & LANs
D
None of the mentioned
32
The interval of frequencies outside which the spectrum is zero is called as ________
A
null to null bandwidth
B
normalized bandwidth
C
absolute bandwidth
D
none of the mentioned
33
The attenuation level in bounded power spectral density is
A
35
B
50
C
35 & 50
D
none of the mentioned
34
Synchronization available in digital communication are
A
Symbol synchronization
B
Frame synchronization
C
Carrier synchronization
D
All of the mentioned
35
Digital system includes
A
Better encryption algorithm
B
Difficult data multiplexing
C
All of the mentioned
D
None of the mentioned
36
Analog to digital conversion includes
A
Sampling
B
Quantization
C
Sampling & Quantization
D
None of the mentioned
37
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
38
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
39
Wired channels are
A
Lossy
B
Lossless
C
Lossy & Lossless
D
None of the mentioned
40
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
41
Which corrects the sampling time problem in a digital system?
A
Interpolator
B
Decimator
C
Equalizer
D
Filter
42
What are the main features of a transmitter?
A
Higher clock speed
B
Linear power amplifier
C
Directional antennas
D
All of the mentioned
43
Transmission media used in low frequency band are
A
Air
B
Water
C
Copper cable
D
All of the mentioned
44
Transmission media used for medium frequency band are
A
Coaxial cable
B
Copper cable
C
Optical fiber
D
All of the mentioned
45
Matched filter technique is used to
A
Increase SNR
B
Decrease SNR
C
SNR is not affected
D
None of the mentioned
46
Matched filter can also be used as least squares estimator.
A
True
B
False
C
D
47
Digital communication system can handle
A
Analog signals
B
1D signals
C
2D signals
D
All of the mentioned
48
The information source of a digital communication system can be
A
Packetized
B
Continuous
C
Packetized & Continuous
D
None of the mentioned
49
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
50
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
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