Error Detection and Correction

Digital Communications Systems

This set of Digital Communication MCQs focuses on “Error Detecting and Correcting Capability and Sampling”.

1. Hamming distance can be given by the number of elements in which
a) They are same
b) They differ
c) Which are non zero
d) None of the mentioned

2. Code strength is characterized by its
a) Minimum distance
b) Maximum distance
c) Code weight
d) Code size

3. The distance between two code-words is equal to the _____ of the third code-word which is the sum of the first two code-words.
a) Size
b) Weight
c) Minimum distance
d) None of the mentioned

4. Error detecting capability is given as
a) Dmin + 1
b) Dmin -1
c) Dmin
d) Dmin/2

5. The minimum distance Dmin can also be given as
a) Dmin >= α + β + 1
b) Dmin <= α + β + 1
c) Dmin >= α + β – 1
d) Dmin <= α + β + 1

6. The number of errors that can be corrected without erasure information is
a) Dmin+1
b) Dmin – 1
c) (Dmin+1)/2
d) (Dmin – 1)/2

7. For better efficiency and simplicity, n should be
a) Maximum
b) Minimum
c) Zero
d) Infinity

8. Nyquist frequency is given by
a) fs
b) 2fs
c) fs/2
d) none of the mentioned

9. Some various types of distortion are
a) Jitter
b) Noise
c) Aperture error
d) All of the mentioned

10. Noise which can affect sampling are
a) Thermal sensor noise
b) Analog circuit noise
c) Thermal sensor & Analog circuit noise
d) None of the mentioned

11. Oversampling can completely eliminate
a) Aperture error
b) Non linearity
c) Quantization error
d) All of the mentioned

12. Sampling can be used in
a) Audio
b) Speech
c) Video
d) All of the mentioned

13. What is the bit depth used for audio recording?
a) 8 bit
b) 16 bit
c) 24 bit
d) All of the mentioned

14. Which factors are measured using the units of lines per picture height?
a) Resolution
b) Sampling rate
c) Resolution & Sampling rate
d) None of the mentioned

15. Sampling of simultaneously two different but related wave-forms is called as
a) Over sampling
b) Complex sampling
c) Inter sampling
d) None of the mentioned

16. Sampling can be done for functions varying in
a) Space
b) Time
c) Space & Time
d) None of the mentioned

17. Reconstruction of continuous signals is done using
a) Decimation algorithm
b) Interpolation algorithm
c) Decimation & Interpolation algorithm
d) None of the mentioned

18. In layering, n layers provide service to
a) n layer
b) n-1 layer
c) n+1 layer
d) none of the mentioned

19. Which can be used as an intermediate device in between transmitter entity and receiver entity?
a) IP router
b) Microwave router
c) Telephone switch
d) All of the mentioned

20. Which has comparatively high frequency component?
a) Sine wave
b) Cosine wave
c) Square wave
d) None of the mentioned

21. Which has continuous transmission?
a) Asynchronous
b) Synchronous
c) Asynchronous & Synchronous
d) None of the mentioned

22. Which requires bit transitions?
a) Asynchronous
b) Synchronous
c) Asynchronous & Synchronous
d) None of the mentioned

23. In synchronous transmission, receiver must stay synchronous for
a) 4 bits
b) 8 bits
c) 9 bits
d) 16 bits

24. How error detection and correction is done?
a) By passing it through equalizer
b) By passing it through filter
c) By amplifying it
d) By adding redundancy bits

25. Which is more efficient?
a) Parity check
b) Cyclic redundancy check
c) Parity & Cyclic redundancy check
d) None of the mentioned

26. Which can detect two bit errors?
a) Parity check
b) Cyclic redundancy check
c) Parity & Cyclic redundancy check
d) None of the mentioned

27. CRC uses
a) Multiplication
b) Binary division
c) Multiplication & Binary division
d) None of the mentioned

28. Which needs re-sending of signal?
a) Error correction
b) Error detection
c) Error correction & detection
d) None of the mentioned

29. Which needs more check bits?
a) Error correction
b) Error detection
c) Error correction & detection
d) None of the mentioned

30. Which gets less affected by noise?
a) Error correction
b) Error detection
c) Error correction & detection
d) None of the mentioned

31. Which is used to protect privacy of the information?
a) Compression coding
b) Source coding
c) Cipher coding
d) None of the mentioned

32. Digital signals are easy for
a) Storage
b) Handling
c) Time dilation
d) All of the mentioned

33. Which are forward error correcting codes?
a) Block codes
b) Convolutional codes
c) Block & Convolutional codes
d) None of the mentioned

34. Which operates on continuous stream of data?
a) Block codes
b) Convolutional codes
c) Block & Convolutional codes
d) None of the mentioned

35. Which is more complex?
a) Encoding
b) Decoding
c) Encoding & Decoding
d) None of the mentioned

36. Which has better minimum distance?
a) Check sum
b) Cyclic redundancy check
c) Check sum & Cyclic redundancy check
d) None of the mentioned

37. In symmetric key cryptosystem, who knows the key?
a) Sender
b) Receiver
c) Sender & Receiver
d) None of the mentioned


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