Constant-weight code: Difference between revisions

Revision as of 23:30, 7 February 2011

Revision as of 11:48, 3 April 2012

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== m of n codes==

An '''''m'' of ''n'' code''' is a separable [[error detection]] code with a code word length of ''n'' bits, where each code word contains exactly ''m'' instances of a "one." A single bit error will cause the code word to have either ''m'' + 1 or ''m'' – 1 "ones.". An example ''m''-of-''n'' code is the [[Two-out-of-five code|2 of 5 code]] used by the [[United States Postal Service]].

The simplest implementation is to append a string of ones to the original data until it contains ''m'' ones, then append zeros to create a code of length ''n''.