Method and apparatus for precompensation value determination in

Details Method and apparatus for precompensation value determination in Method and apparatus for precompensation value determination in

1992-01-31

1994-10-18

Beausoliel, Jr., Robert W.

Excavating

371 214, G11C 2900

Patent

active

053575202

ABSTRACT:
A method and apparatus are provided for determining an adjustable precompensation value in a partial-response maximum-likelihood (PRML) data channel. The PRML data channel includes an adjustable precompensation function for modulating the write data waveform. A predetermined test pattern is written using write circuitry in the disk file. The predetermined test pattern is insensitive to channel misequalization and provides a reference for gain and timing control. The written predetermined test pattern is read back using read circuitry in the disk file. An error in sample values in the read back predetermined test pattern is identified using logic provided in the PRML data channel while performing a standard read operation of a data sector written with the test pattern. The adjustable write precompensation value is adjusted responsive to identifying an error.

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