Hybrid Equalized Partial Response Path-Feedback Maximum Likelihood for 35.4 GB Blu-ray Disc ROM

Abstract

The decoding method with larger margin has been required according to the recent high density optical recordings. Since the optical reproduced signal has a strict cutoff of modulation transfer function (MTF), the high linear density equalization will cause the equalization error. In such a case, adaptive Viterbi [rf1,rf2,rf3] has been investigated as a decoding method which compensates tangential inter-symbol interference (ISI) and the scanty high frequency components. This fundamental theory is based on path feedback Viterbi detection. [rf4] We have developed hybrid equalized partial response path-feedback maximum likelihood (HEPR-PFML) which compensates the scanty frequency components more efficiently than conventional adaptive Viterbi. By using this system, the decoding performance is not only improved, but phase locked loop (PLL) will be stable because of the clear timing error information. We will show the experimental results for the higher density 35.4 GB Blu-ray Disc ROM (BD-ROM) than standard linear densities.