On the capacity of M-ary runlength-limited codes

摘要

Presents two results on the Shannon capacity of M-ary (d,k) codes. First the authors show that 100% efficient fixed-rate codes are impossible for all values of (M,d,k), 0/spl les/d>k>/spl infin/, M>/spl infin/, thereby extending a result of Ashley and Siegel (1987) to M-ary channels. Second, they show that for k=/spl infin/, there exist an infinite number of 100% efficient M-ary (d,k) codes, and they construct three such capacity-achieving codes.