An advanced PRML data recovery system is presented for a high-density recording. The system consists of three major hardware units, which are DC offset compensator, adaptive equalizer, and Viterbi detector with level adaptation scheme. The experiment based on an improved PRML scheme and FPGA hardware realization shows highly reliable performance of data detection up to 35GB recording density. The SER experiment result for 35GB shows that the detector using the proposed PRML yields a result to meet the SER limit of 4.0x10<sup>-3</sup> with a margin of 0.45° for tangential and 0.55° for radial tilt. And the base SER marks 7.0x10<sup>-5</sup> when there is no tangential and radial tilt error.
In this paper, a new method using an eye pattern is proposed to measure the signal quality for high-density recording systems. The experiment shows that the new method has a strong relation to SER of the system using PRML algorithm.
A new fast and accurate digital frequency detection algorithm for the optical drive system is presented. The proposed algorithm, which is based on the analysis of data histograms, improves the initialization time and the detection resolution.