Patent ID: 6977970
Filing Date: 2005-12-20
Classification: G11B,H04L

Abstract:
1. A data reproducing apparatus comprising: an equalizer which equalizes an input digital signal; a data detector which detects the equalized digital signal based on partial response maximum likelihood; and a level decision unit which detects levels corresponding to decision levels used in the data detector from the output of the equalizer and feeds back corrected decision levels to the data detector, the corrected decision levels adaptively varying with the output level of the equalizer, wherein the level decision unit comprises: a plurality of delay units which temporarily store sequential ones of the equalized digital signals; a level detector which compares consecutive two or three sample data provided from the plurality of delay units to detect decision levels used in the data detector and which outputs a plurality of level decision enable signals and a plurality of selection signals; a multiplexer which selectively outputs the outputs of the plurality of delay units in response to the selection signals; and a plurality of averagers each of which averages the outputs of the multiplexer on being enabled by one of the plurality of enable signals and feeds back an averaged corrected decision level as the corrected decision level to the data detector.