An enumerative coding technique for DC-free runlength-limited sequences

We present an enumerative technique for encoding and decoding dc-free runle ngth-limited sequences. This technique enables the encoding and decoding of sequences approaching the maxentropic performance bounds very closely in t erms of code rate and low-frequency suppression capability. Use of finite-p recision floating-point notation to express the weight coefficients results in channel encoders and decoders of moderate complexity. For channel const raints of practical interest, the hardware required for implementing such a quasi-maxentropic coding scheme consists mainly of a ROM of at mast 5 kB.