Patent ID: 6393598
Filing Date: 2002-05-21
Classification: G11B,H03M

Abstract:
A data sequence detector for use in a digital magnetic recording and read-back system for obtaining an estimated sequence of bits of binary data corresponding to an original sequence of bits of binary data, wherein the original sequence is selectively precoded into a write sequence of bits of binary data which are represented by corresponding magnetization regions in a magnetic medium; the detector comprising:an input for receiving a data waveform obtained at least in part from magnetization regions in the magnetic medium; circuitry configured according to a predetermined state machine model having at least 8 states; and wherein the circuitry is configured to perform steps of: (a) recovering the estimated sequence from the data waveform; (b) converting the estimated sequence of bits of binary data into a waveform sequence of sample values; (c) performing data waveform based magnitude determinations using at least four values from the waveform sequence wherein possible distortions of the data waveform are caused at least in part by the data waveform being obtained from primary corresponding magnetization regions and an adjacent magnetization region in the magnetic medium, wherein the at least four sample values used in magnitude determinations include a trailing sample value which follows sample values corresponding to the primary magnetization regions, and a leading sample value which precedes sample values corresponding to the primary magnetization regions; and (d) compensating possible distortions of some of these waveform sequence values by use of detection criteria based on corresponding combinations of sample values from the waveform sequence for at least some subsequences of three sample values from the waveform sequence which detection criteria differ from the distortion free detection criteria which would otherwise be used based on a corresponding combination of fewer sample values from the waveform sequence.