What will be the minimum Hamming distance for the following coding scheme?
2017
What will be the minimum Hamming distance for the following coding scheme?

- A.
1
- B.
2
- C.
3
- D.
4
Attempted by 269 students.
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Correct answer: B
Concept: The minimum Hamming distance (dmin) of a coding scheme is the smallest number of bit positions in which any two distinct valid codewords differ. The Hamming distance between two equal-length codewords is the count of positions where their bits disagree.
Application: The four valid codewords are 00111, 01001, 10101 and 11100. Compare every one of the six possible pairs and count the differing positions:
00111vs01001: differ at positions 2, 3, 4 → distance = 300111vs10101: differ at positions 1, 4 → distance = 200111vs11100: differ at positions 1, 2, 4, 5 → distance = 401001vs10101: differ at positions 1, 2, 3 → distance = 301001vs11100: differ at positions 1, 3, 5 → distance = 310101vs11100: differ at positions 2, 5 → distance = 2
Cross-check: The smallest of the six distances {3, 2, 4, 3, 3, 2} is 2, achieved by the pairs 00111–10101 and 10101–11100. No pair differs in only one position, so the distance cannot be 1.
Result: the minimum Hamming distance of this coding scheme is 2.