Construction of high rate codes from an infinite memory constraint graph

The authors explain and demonstrate specific techniques used in constructing codes for a class of graphs. A constraint graph describing sequences for a novel recording and detecting technique can be used as the basis for constructing both rate 4/5 and a rate 5/6 sliding block decodable codes. Normally, a straightforward application of the state-splitting algorithm of R. Adler et al. (1983) could be used to construct such codes. However, the constraint graph of this problem has infinite memory and thus requires code construction techniques beyond that given by Adler et al. The modifications to the state-splitting algorithm that were used to construct highly efficient codes from an infinite memory constraint graph are discussed