Home
MCQS
MCQs Practice Portal - robustlifestyles.com
Electrical measurements MCQ Quiz Hub
Digital Communications MCQs set-9
Choose a topic to test your knowledge and improve your Electrical measurements skills
1. Syndrome is calculated by
HT/r
rHT
rH
None of the mentioned
2. The _____ of the code-word is the number of non zero elements.
Size
Weight
Distance
Subspace
3. Some examples of linear codes
Hamming code
Reed-Solomon code
Parity code
All of the mentioned
4. The measure of the amount of redundancy is given by
Code size
Code weight
Code rate
Minimum distance
5. The number of k bit shift over which a single information bit influences the encoder output is given by
Code rate
Constraint length
Code length
Code weight
6. The method used for representing convolution encoder are
Connection pictorial
State diagram
Tree diagram
All of the mentioned
7. Periodic truncation is done by
Appending zero to end of the input data sequence
Appending zero to the beginning of the input data sequence
Appending one’s to end of the data sequence
Appending one’s to beginning of the data sequence
8. Finite state machines have
Past memories also
Only present and future memories
Only future memories
Only present memories
9. How many number of transitions can be made at each bit time?
One
Two
Three
Half
10. In trellis diagram, the number of nodes ______ at successive branching.
Increases by 1
Doubles
Triples
None of the mentioned
11. Example for convolution encoder state diagram is
Tree diagram
Trellis diagram
Tree & Trellis diagram
None of the mentioned
12. In maximum likelihood decoding technique, the likelihood function compares the
Joint probabilities
Individual probabilities
Conditional probabilities
None of the mentioned
13. In maximum likelihood detector the error probability is
Maximum
Minimum
Zero
None of the mentioned
14. For a binary code, the maximum number of possible sequence made up of L branch words is
L2
2L
2L
L/2
15. If the quantization level of a demodulator output is ________ then it is called as soft decision decoding.
Equal to 2
More than 2
Less than 2
None of the mentioned
16. Soft decision decoding requires
Less memory
More memory
More speed
None of the mentioned
17. A binary symmetric channel is a
Discrete memoryless channel
Continuous memoryless channel
Discrete memory channel
Continuous memory channel
18. Binary symmetric channel is hard decision channel.
True
False
19. Gaussian channel is a hard decision channel.
True
False
20. Branch word synchronization is the process of determining the
Beginning of received sequence
Beginning of transmitted sequence
End of received sequence
End of transmitted sequence
21. Which distance is related to the error correcting capability of the code?
Maximum distance
Minimum distance
Maximum & Minimum distance
None of the mentioned
22. A catastrophic error is an event whereby ______ number of code symbol error causes _______ number of decoded data error bits.
Finite, finite
Finite, infinite
Infinite, finite
Infinite, infinite
23. A code should be selected such that it should
Not have catastrophic error propagation
Have minimum free distance
All of the mentioned
None of the mentioned
24. The error correcting capability of a code scheme increases as the
Number of channel symbols per information bit increases
Bandwidth increases
Information per bit increases
All of the mentioned
25. Which has a limited resolution?
Hard decision decoder
Soft decision decoder
Hard & Soft decision decoder
None of the mentioned
26. Which parameter is used in soft decision algorithm?
Euclidean distance
Euclidean distance squared
Euclidean distance & distance squared
None of the mentioned
27. Which factor is desirable?
Minimum correlation
Maximum correlation
Maximum distance
None of the mentioned
28. Soft decision results in
Increase in complexity
Decrease in storage
Increase in complexity & Decrease in storage
None of the mentioned
29. A feedback decoder makes hard decision.
True
False
30. The look ahead length L is given by
m+1
m-1
(m+1)/2
1-m
31. On increasing L
Coding gain increases
Complexity increases
Coding gain & Complexity increases
None of the mentioned
32. Reed Solomon codes are
Non binary
Cyclic
Non binary & Cyclic
None of the mentioned
33. The minimum distance for Reed Solomon code is given by
n+k+1
n-k+1
1-n-k
1+n-k
34. R-S codes have
High code rate
Low redundancy
High code rate & Low redundancy
None of the mentioned
35. Greater the redundancy greater will be the error correcting capability.
True
False
36. A primitive element are those which yield ______ when raised to higher order exponents.
All zero elements
Non zero elements
Unity elements
None of the mentioned
37. If the inversion was performed correctly, then the multiplication of the original matrix with the inverted matrix should yield identity matrix. This is known as
Identity theorem
Safety theorem
Multiplication theorem
Inversion theorem
38. Compact disc is used for
Digital storage
Reproduction of audio signals
Digital storage & Reproduction of audio signals
None of the mentioned
39. Sources of channel errors are
Finger prints
Air bubbles
Unwanted particles
All of the mentioned
40. The CIRC error control scheme includes
Correction
Concealment
Correction & Concealment
None of the mentioned
41. Decoding step consists of
De-interleaving
Decoding
De-interleaving & Decoding
None of the mentioned
42. The ______ the error correcting capability used, the _____ will be the erasure correcting capability.
Larger, smaller
Smaller, larger
Smaller, smaller
Larger, larger
43. In interpolation
New samples are added
Unreliable samples are removed
New samples are added & Unreliable samples are removed
None of the mentioned
44. The channel that exhibits multi-path fading
Has memory
Exhibits mutually dependent signal transmission impairments
Received signal will be distorted
All of the mentioned
45. Separating the symbols makes the channel memory-less.
True
False
46. The minimum end to end delay in block interleaving is
2MN+2M+2
2MN-2M+2
2MN-2M-2
2MN+2M-2
47. A concatenated code uses
One level of coding
Two levels of coding
Three levels of coding
None of the mentioned
48. A concatenated code has
Low error rate
High complexity
Low error rate & High complexity
None of the mentioned
49. The performance of non binary concatenated code depends on
Bit errors
Symbols errors
Bit & Symbols errors
None of the mentioned
50. Concatenated code is an example of
Error detecting code
Error correcting code
Error detecting & correcting code
None of the mentioned
Submit