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Digital Communications MCQs set-3

Review each question and reveal answers to strengthen your understanding

1 Modulation channel consists of
✅ Correct Answer: 3
2 Modulation channel does not accept an analog input signal.
✅ Correct Answer: 2
3 If operating frequency bands are higher ______ is available.
✅ Correct Answer: 2
4 Ground wave communication occurs in
✅ Correct Answer: 3
5 Sampling theorem is used for converting
✅ Correct Answer: 3
6 A signal can be recovered from its sample by using
✅ Correct Answer: 1
7 Which is practically realizable?
✅ Correct Answer: 1
8 In flat top sampling scheme, ______ is kept constant after sampling.
✅ Correct Answer: 1
9 Loop filter is a ______ used to reduce noise.
✅ Correct Answer: 1
10 A stationary stochastic process has
✅ Correct Answer: 2
11 The power spectral density function of the stochastic process is
✅ Correct Answer: 1
12 For a periodic function, the spectral density and auto correlation functions form
✅ Correct Answer: 1
13 The capacity of a channel is given by
✅ Correct Answer: 3
14 In a communication system, a process in which statistical averages and time averages are equal is called as
✅ Correct Answer: 2
15 A rectangular pulse of duration T is applied to a matched filter. The output of the filter is a
✅ Correct Answer: 3
16 The line code has a zero dc component for pulse transmission of random binary data is
✅ Correct Answer: 3
17 The auto-correlation of white noise is
✅ Correct Answer: 1
18 Ionospheric communication can take place in
✅ Correct Answer: 1
19 Satellite communication takes place in
✅ Correct Answer: 3
20 The weighing matrix is
✅ Correct Answer: 3
21 Non uniform tree _____ bit rate.
✅ Correct Answer: 1
22 Two clock with rates T1 and T2 are incommensurate if its ratio is
✅ Correct Answer: 2
23 Possible timing error detection methods are
✅ Correct Answer: 3
24 Which has minimum power loss during transmission?
✅ Correct Answer: 1
25 Voltage generated by lightning is an example for
✅ Correct Answer: 1
26 In the digital communication system, signals in different frequency bands are
✅ Correct Answer: 1
27 Properties of impulse function are
✅ Correct Answer: 4
28 Properties of Fourier transform are
✅ Correct Answer: 4
29 A base-band signal can be up-converted using
✅ Correct Answer: 2
30 A band-pass signal can be down-converted using
✅ Correct Answer: 2
31 In down-conversion multiplication with cosine wave is followed by
✅ Correct Answer: 1
32 ADSL has _____ information channels.
✅ Correct Answer: 2
33 Fourier transform of a signal gives the
✅ Correct Answer: 3
34 Random things in a communication system are
✅ Correct Answer: 4
35 Which can be used for periodic and non periodic?
✅ Correct Answer: 2
36 A band-pass signal has a Fourier transform equal to
✅ Correct Answer: 2
37 Which are orthonormal signal representation?
✅ Correct Answer: 4
38 Constellation diagram is plotted in
✅ Correct Answer: 2
39 Cumulative distributive function is
✅ Correct Answer: 3
40 Which are non negative functions?
✅ Correct Answer: 3
41 The sampling process includes methods such as
✅ Correct Answer: 2
42 The output of sampling process are called as ________
✅ Correct Answer: 2
43 According to Sampling theorem
✅ Correct Answer: 4
44 The fourier tranform of one impulse train is also another impulse train with a period of the output equal to the
✅ Correct Answer: 2
45 The process in which the top of each pulse in the output samples retains the shape of the analog segment is called as ________
✅ Correct Answer: 1
46 The effects of aliasing are ________
✅ Correct Answer: 3
47 Aliasing can be removed using
✅ Correct Answer: 3
48 Which process is more economical?
✅ Correct Answer: 2
49 Flat top sampling or practical sampling has
✅ Correct Answer: 2
50 Multiplication of input signal with pulse train is done in ________ sampling.
✅ Correct Answer: 2
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