Digital Communications

Error Detecting and Correcting Capability and Sampling

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Nyquist frequency is given by
fs
2fs
fs/2
none of the mentioned
Explanation:
Nyquist frequency is given as fs/2 where fs is the sampling frequency.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The number of errors that can be corrected without erasure information is
Dmin+1
Dmin – 1
(Dmin+1)/2
(Dmin – 1)/2
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.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
The minimum distance Dmin can also be given as
Dmin >= α + β + 1
Dmin <= α + β + 1
Dmin >= α + β – 1
Dmin <= α + β + 1
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.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Hamming distance can be given by the number of elements in which
They are same
They differ
Which are non zero
None of the mentioned
Explanation:
Hamming distance between two code words can be given by the number of elements in which they differ.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
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.
Size
Weight
Minimum distance
None of the mentioned
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.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Code strength is characterized by its
Minimum distance
Maximum distance
Code weight
Code size
Explanation:
The smallest number of the set given the minimum distance of the code. This minimum distance characterizes the strength of the code.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Noise which can affect sampling are
Thermal sensor noise
Analog circuit noise
Thermal sensor & Analog circuit noise
None of the mentioned
Explanation:
Some of the noises that can cause distortion in sampling are thermal sensor noise, analog circuit noise etc.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Error detecting capability is given as
Dmin + 1
Dmin -1
Dmin
Dmin/2
Explanation:
The error detecting capability is given as e = Dmin – 1, where Dmin is the minimum distance of the code word.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Some various types of distortion are
Jitter
Noise
Aperture error
All of the mentioned
Explanation:
Various types of distortion are aliasing, jitters, aperture error, noise, error due to non linear effects, error due to quantization etc.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
For better efficiency and simplicity, n should be
Maximum
Minimum
Zero
Infinity
Explanation:
For real world codes, n should be minimum for better efficiency and simplicity.