Constrained Code and Partial-Response Maximum-Likelihood Detection for High Density Multi-Level Optical Recording Channels

Abstract

A new efficient four-ary (1,4) run-length limited (RLL) code is presented, which is intended for high density multi-level optical recording channels. By using proposed hybrid DC control scheme, the new code can achieve acceptable DC suppressing characteristics while maintaining high code rate. The bit error rate (BER) performances of this new code on blue laser recording systems are evaluated by using partial-response maximum-likelihood (PRML) detection. The feasibility of using four-ary RLL modulation and PRML detection is studied in this paper, and these techniques show great potential to be applicable in high-density multi-level optical recording channels.