BCH code

A BCH (Bose-Chaudhuri-Hochquenghem) code is a multilevel, cyclic, error-correcting, variable-length digital code used to correct errors up to approximately 25% of the total number of digits.

Note: BCH codes are not limited to binary codes, but may be used with multilevel phase-shift keying whenever the number of levels is a prime number or a power of a prime number, such as 2, 3, 4, 5, 7, 8, 11, and 13. A BCH code in 11 levels has been used to represent the 10 decimal digits plus a sign digit.

BCH codes make use of field theory and polynomials over that field. The way the check polynomial is constructed provides the key to indicating that an error has occured.

Source: from Federal Standard 1037C