Abstract
The multilevel run-length-limited (ML-RLL) modulation recording can improve the capacity and the data transfer rate of the optical disc without changing the optical and mechanical units. A viterbi detector with feedback is used to improve the performance of the partial-response maximum likelihood (PRML) system for ML-RLL optical recording. It can avoid the complexity of viterbi detector caused by the overlength of the memory length of the partial-response mode. The principle, implementation and the simulated results of the viterbi detector with feedback used in ML-RLL system are all presented.