Permutation (d, k) codes: Efficient enumerative coding and phrase length distribution shaping

In this correspondence, we introduce a new enumerative encoding method for (d, k) codes. The encoding algorithm, which is based on enumeration of mult iset permutations, is conceptually simpler and computationally less expensi ve than other algorithms proposed thus far. We also describe a new applicat ion of enumerative encoding methods for phrase length distribution shaping of run-length-limited (RLL) sequences. We demonstrate that by reducing the probability of occurrence of long phrases in maxentropic RLL sequences, the frequency of patterns that account for most of the errors in magnetic reco rding systems can be decreased.