Fujitsu Corporation

Kenichi Yamakura

Masaru Sawada

Koji Horibe

Hideaki Tanishima

Tsunehiko Moriuchi

Manabu Nakano

Tsuyoshi Tomita

Yoshitaka Nakata

Fumiaki Uematsu

Masashi Yamawaki

Hirofumi Yamawaki

A signal processor used to process an analog read signal representing data stored on a magnetic disk allows for a faster read operation without requiring an increase in its circuit area or buffer memory space. The signal processor includes a decision feedback equalizer which selectively provides a feedback signal added to a read signal in reproducing data read from a storage medium. The signal processor also performs error correction. In performing error correction, the load of the error correcting process is detected and the processing speed is altered depending upon the detected load.

Signal processor having feedback loop control for decision feedback equalizer

It is intended to provide a recording-medium operating device, a clock signal generating device for the recoding-medium operating device, and a method for generating a clock signal for the recoding-medium operating device that satisfy both operation with a wide-range data transfer rate using delay line provided with not so large number of stages and high correction accuracy and are advantageous in terms of low power consumption and suppression of noises. A reference clock group &#xd8;through &#xd8;x different in phase are obtained by a PLL. One of the reference clock group is selected by a clock selector. A selected clock signal is inputted to a delay circuitand one of output clocks from a delay lineis selected by a selector. With structure as such, selection by the clock selectorand the selectoris controlled so as to make phase difference between a clock signal and an RF signal minimum. Thereby, time equivalent to phase difference of adjoining two reference clocks is sufficient enough as total delay quantity of the delay line

Recording-medium operating device, clock signal generating device and method for generating clock signal

A data error correcting method and apparatus reads two dimensional block data having row data and row error correcting codes and column data and column error correcting codes. In the block data, one column error correcting code is assigned to one column data group, and individual column data groups and individual column error correcting codes are alternately arranged. A control unit corrects errors in the block data on a row by row basis using the row error correcting codes and the row data. The control unit also corrects errors on a column by column basis, in parallel with the row errors, using the column error correcting codes and the column data. The control unit includes a compensation input data generator having a data adjustor and a Galois multiplier. The data adjustor computes a Compensation Galois constant for compensating the input order of the data.

Data error correcting method and apparatus

An error correcting method reducing the time needed to provide error correction using a buffer memory. The method includes performing row error correction by using a plurality of rows of data to produce row-corrected block data and performing column error correction by using the plurality of columns of data to produce column-corrected block data. In addition, at least one of the performing row error correction and performing column error correction operates using a plurality of rows or columns of data in units of a predetermined number of rows or columns so as to provide error correction for the plurality of rows or columns in parallel.

Method and apparatus for correcting data errors

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Kasugai, Japan

Kenichi Yamakura