R4RIN
MCQS
Electrical measurements MCQ Quiz Hub
Digital Communications MCQs set-1
Choose a topic to test your knowledge and improve your Electrical measurements skills
1. Which circuit is called as regenerative repeaters?
Analog circuits
Digital circuits
Amplifiers
A/D converters
2. What are the advantages of digital circuits?
Less noise
Less interference
More flexible
All of the mentioned
3. How many bytes does a gigabyte have?
1 million bytes
10 million bytes
1 billion bytes
10 billion bytes
4. What is the ASCII value of space?
32
48
96
65
5. Which block or device does the data compression?
Channel encoder
Source encoder
Modulator
None of the mentioned
6. What is the code rate?
k/n
n/k
All of the mentioned
None of the mentioned
7. Pulse shaping is done by which block or system?
Encoder
Baseband modulator
Pulse code modulator
Demodulator
8. Equalizer is used for?
Filtering
Diminish distortion
All of the mentioned
None of the mentioned
9. Source coding block is used for?
Compressing
Digitizing
A/D conversion
All of the mentioned
10. Which measurement considers phase as an important parameter?
Coherent
Non-coherent
All of the mentioned
None of the mentioned
11. What is the period of a signal x(t)?
T
2T
T/2
None of the mentioned
12. Which of the given signals are periodic?
x(t) = 4 cos(5πt)
x(t) = u(t) – 1/2
x(t) = 4u(t) + 2sin(3t)
x[n] = 2sin(3n)
13. Check whether the signal is periodic or not? x(t) = cos(4t) + 2sin(8t)
Periodic with period π/2
Periodic with period 2
Periodic with period 2/π
Not periodic
14. Find the periodicity of the following signal. x(t)=cos((2π/7)t)sin((3π/5)t)
30
7
35
5/3
15. Find the fundamental period of 1+sin^2 (3π/5)n.
10/3
5
3π/5
None of the mentioned
16. Which signal is called as energy signal?
Finite energy and zero power
Finite energy and non-zero power
Infinite energy and zero power
Infinite energy and non-zero power
17. Which signal is said to be power signal?
Infinite power and zero energy
Infinite power and non-zero energy
Finite power and infinite energy
Finite power and zero energy
18. Continuous Impulse signal is a power or energy signal?
Power signal
Energy signal
Both power and energy
Neither power nor energy signal
19. Discrete impulse signal is a power or energy signal?
Power signal
Energy signal
Both power and energy signal
Neither power or energy signal
20. A unit impulse function has?
Large amplitude
Zero pulse width
Unity weight
All of the mentioned
21. Power spectral density function is a?
Real and even function
Non negative function
Periodic
All of the mentioned
22. Energy spectral density defines
Signal energy per unit area
Signal energy per unit bandwidth
Signal power per unit area
Signal power per unit bandwidth
23. Power spectrum describes distribution of _________ under frequency domain.
Mean
Variance
Gaussian
None of the mentioned
24. How can power spectral density of non periodic signal be calculated?
By integrating
By truncating
By converting to periodic
None of the mentioned
25. What is Wiener-Khinchin theorem?
Spectral density and auto-covariance makes a fourier transform pair
Spectral density and auto-correlatioon makes a fourier tranform pair
Spectral density and variance makes a fourier tranform pair
None of the mentioned
26. According to Parseval’s theorem the energy spectral density curve is equal to?
Area under magnitude of the signal
Area under square of the magnitude of the signal
Area under square root of magnitude of the signal
None of the mentioned
27. Spectogram is the graph plotted against?
Frequency domain
Time domain
Frequency & Time domain
None of the mentioned
28. Autocorrelation is a function which matches
Two same signals
Two different signal
One signal with its delayed version
None of the mentioned
29. Autocorrelation is a function of
Time
Frequency
Time difference
Frequency difference
30. Autocorrelation is maximum at _______
Unity
Origin
Infinite point
None of the mentioned
31. Autocorrelation function of periodic signal is equal to _______
Energy of the signal
Power of the signal
Its area in frequency domain
None of the mentioned
32. Autocorrelation is a _______ function.
Real and even
Real and odd
Complex and even
Complex and odd
33. Autocorrelation function of white noise will have?
Strong peak
Infinite peak
Weak peak
None of the mentioned
34. Random variables give relationship between _____
Two random events
Probability of occurence of two random events
Random event and a real number
Random event and its probability of occurrence
35. The distribution function of random variable is
P(X less than or equal to x)
P(X greater than or equal to x)
P(X less than x)
P(X greater than x)
36. The distribution function of -(infinity) and (infinity) is _____
0 and 1
1 and 0
Both 0
Both 1
37. The value of the probability density function of random variable is
Positive function
Negative function
Zero
One
38. Which gives the measure of randomness of the random variable?
Mean
Variance
Standard variance
Pdf
39. Random process is a function of ______
Random event and time
Random event and frequency
Random event and real number
None of the mentioned
40. A random process is called as stationary in strict sense if
Its statistics vary with shift in time origin
Its statistics does not vary with shift in time origin
Its autocorrelation vary with shift in time
Its autocorrelation does not vary with shift in time
41. For a stationary process, autocorrelation function depends on
Time
Time difference
Does not depend on time
None of the mentioned
42. The autocorrelation function is maximum at
Origin
Infinity
Origin & Infinity
None of the mentioned
43. White noise has _____ mean and ______ variance.
Zero and zero
Finite and zero
Zero and finite
One and zero
44. The process of data conversion along with formatting the data is called as ______
Formatting
Modulation
Source coding
Amplifying
45. Formatting is the process which includes
Pulse code modulation
Sampling
Quantization
All of the mentioned
46. Analog information is converted to digital data using
Sampling
Quantization
Coding
All of the mentioned
47. The process that transforms text into binary digits is called as _______
Binary coding
Data coding
Character coding
Sampling
48. For the number of bits, k=1 and number of symbols, M=2 the system is called as
Unary
Binary
Quarternary
None of the mentioned
49. Perform the bit stream partitioning and find the 8-ary waveform for the word ‘THINK’.
1204443464
4643444021
1240443464
none of the mentioned
50. Find the 32-ary waveform for the word ‘THINK’.
514172520
202517415
541172520
None of the mentioned
Submit