The Hamming 7-4 Error Correcting Code

Hamming Code is an example of a code that can correct single errors. This code exists for many different word lengths. An example is the Hamming 7-4 Code, it consists of 7 information bits and 4 control bits, hence the code word consists of 11 bits.

So, assume that we have the following information bits:

index	1	2	3	4	5	6	7
information word	w1	w2	w3	w4	w5	w6	w7

The code word, consisting of the above information bits and the four additional control bits, is constructed in a special way, namely:

index	1	2	3	4	5	6	7	8	9	10	11
code word	c1	c2	w1	c3	w2	w3	w4	c4	w5	w6	w7

Further, in depth explanation of the Hamming 7-4 Code is available:

• Hamming 7-4 Code in action: demonstrates how the Hamming Code works between peer Data-Link protocol entities.
• Construction of Hamming 7-4 Code: Demonstrates how to construct the Hamming Code given a 7-bit information word.
• Error Correction of Hamming 7-4 Code: Demonstrates how an error in a received 11-bit code-word is corrected.