PRML detection of multi-level run-length limited DVD system
Hua Hu, Longfa Pan, Yi Ni · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2007
Multi-level optical recording using run-length-limited (RLL) modulation is a novel method to significantly increase the information recording density without changing optical or mechanical parameters. In this paper, the experimental results of four-level RLL modulation on read-only digital versatile discs (DVD-ROM) are introduced. A new DC-free 4-level RLL (2, 8) code with code rate of 8/10 (bits/symbol) is designed, and a partialresponse maximum-likelihood (PRML) detector is adopted to evaluate the detection performance of multi-level readout signals. By analyzing and comparing the simulation performances of different PRML schemes, we conclude that PR(1, 2, 2, 2, 1) target is preferred to be applied in four-level RLL modulation DVD channels.