# Digital Communications Questions and Answers – Error Detecting and Correcting Capability and Sampling

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
View Answer

Answer: b
Explanation: Hamming distance between two code words can be given by the number of elements in which they differ.

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

Answer: a
Explanation: The smallest number of the set given the minimum distance of the code. This minimum distance characterizes the strength of the code.

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
View Answer

Answer: b
Explanation: The sum of two code words gives a third code which is also a linear code. The distance between two code words is equal to the weight of the third code word.
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4. Error detecting capability is given as
a) Dmin + 1
b) Dmin -1
c) Dmin
d) Dmin/2
View Answer

Answer: b
Explanation: The error detecting capability is given as e = Dmin – 1, where Dmin is the minimum distance of the code word.

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
View Answer

Answer: a
Explanation: If a code can correct α errors and detect β errors, then the minimum distance can be given by the relation Dmin >= α + β + 1.
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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
View Answer

Answer: d
Explanation: If a code has a minimum distance dmin then dmin-1 erasures can be reconstituted. The number of errors that can be corrected without erasure information is (dmin-1)/2.

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

Answer: b
Explanation: For real world codes, n should be minimum for better efficiency and simplicity.
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8. Nyquist frequency is given by
a) fs
b) 2fs
c) fs/2
d) none of the mentioned
View Answer

Answer: c
Explanation: Nyquist frequency is given as fs/2 where fs is the sampling frequency.

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

Answer: d
Explanation: Various types of distortion are aliasing, jitters, aperture error, noise, error due to non linear effects, error due to quantization etc.
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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
View Answer

Answer: c
Explanation: Some of the noises that can cause distortion in sampling are thermal sensor noise, analog circuit noise etc.

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

Answer: a
Explanation: Oversampling can completely eliminate aperture error and aliasing but can only reduce quantization error and non linearity to some extent.

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

Answer: d
Explanation: Sampling can be used in audio sampling, speech sampling and also in video sampling.

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

Answer: d
Explanation: Audio is recorded at 8 bit, 16 bit, and also 24 bit depth which yield theoretically maximum SNR.

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
View Answer

Answer: c
Explanation: Sampling rate and resolution in spatial directions can be measured in units of lines per picture height.

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
View Answer

Answer: b
Explanation: Complex sampling is the process of simultaneously sampling two different but related signals.

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

Answer: c
Explanation: Sampling can be done for functions varying in time, frequency, space or any other dimension.

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

Answer: b
Explanation: Reconstruction of signals from the samples is done using interpolation algorithm.

Sanfoundry Global Education & Learning Series – Digital Communications.

To practice all areas of Digital Communication, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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