An error correcting code has the following code words: 00000000, 00001111,…

2007

An error correcting code has the following code words: 
00000000, 00001111, 01010101, 10101010, 11110000.
What is the maximum number of bit errors that can be corrected ?

  1. A.

    0

  2. B.

    1

  3. C.

    2

  4. D.

    3

Attempted by 372 students.

Show answer & explanation

Correct answer: B

Answer: 1 bit

Reasoning:

  • Compute Hamming distances between codewords. Distances include several pairs separated by 4 bits (for example, 00000000 vs 00001111 differ in 4 positions), and some pairs differ in 8 bits.

  • The minimum Hamming distance d_min among all codeword pairs is 4.

  • A code can correct up to t = floor((d_min - 1)/2) bit errors.

  • Thus t = floor((4 - 1)/2) = floor(1.5) = 1. The code can correct at most one bit error.

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