Adaptive signal processing method using PRML for high density optical disks

摘要

Recently, many DVD recording equipments are put on the market, and it begins to spread in the same way as the VCR. And, there is much demand for the optical storage system with high speed and large capacity for digital high definition broadcast. But it becomes so difficult to keep the data reliability with increasing the recording speed and density, because the signal to noise ratio goes worse and recording control of the phase changed mark becomes difficult. To improve the error rate of reproduced data, PRML (partial Response Maximum Likelihood) decoding is expected being used. We have developed more progressed method of PRML, where the difference of the reproduced waveform is analyzed and the PRML decoder is compensated. In this paper we report the analysis of reproduced waveform and the effect of developed PRML algorithm.