IMPROVED DISTANCE M-ARY (D, K) CODES FOR HIGH-DENSITY RECORDING

We consider the problem of coding for a high density recording channel . New recording media have been developed that support unsaturated, M- ary (M greater-than-or-equal-to 3) signaling. This paper is concerned with the analysis and design of M-ary runlength limited (RLL) codes fo r multi-amplitude, linear recording channels. The codes achieve the la rgest known coding density and have improved minimum distance over an ordinary Adler-Coppersmith-Hassner code designed via the state splitti ng algorithm. Comparisons are made with Ungerboeck-style trellis codes with comparable complexity.