Term used in digital signal transmission, signal processing; measure of the resilience of a code against transmission errors (literature: R. W. Hamming, Error Detecting and Error Correcting Codes, Bell Syst. Techn. J. 29 (1950)).
If two code words of the same length are compared with each other position for position, the Hamming distance is equal to the number of bits (minimum) where they differ, DIN 44 300.
Example: some dual system or BCD code strings have a Hamming distance of d = 1; single errors producing a signal change at just one binary position will cause them to look like another code word (Figure).
A code string with a Hamming distance of d = 2 offers greater transmission security, since single errors can be detected and corrected. Only double errors will cause something to look like another code word.
Illustration of the Hamming distance for the dual system