Hybrid equalized partial response path-feedback maximum likelihood toward higher density Blu-ray disc

Recently, high density optical recording systems like BD (Blu-ray disc) have been standardized regarding a PRML (partial response maximum likelihood) signal processing technology, which has been thoroughly investigated on high density magnetic recording channels for many years. In order to gain a margin of optical disc drives, PFML (path-feedback maximum likelihood), which is also known as adaptive Viterbi, has been also developed in recent years. In this paper, we propose a new signal processing system, which equalizes the waveform causally, enhances the performance of the PFML detector and provides a stable PLL (phase locked loop) towards much higher density formats than standard BDs.