PRML process of multilevel run-length-limited modulation recording on optical disc

We introduce partial-response maximum-likelihood (PRML) signal process to increase the accuracy of reading multilevel signal from a multilevel run-length-limited (ML-RLL) recorded disc. The reason is that the traditional slicer detection is no longer suitable for detecting ML-RLL signal. In this paper, we also present several partial-response methods and their corresponding maximum-likelihood sequential estimation (MLSE) rules for ML-RLL modulation signal detecting.