Disk apparatus having automatic adjustment of adaptive filter equalization parameter using training pattern

摘要

A training pattern which is used for a waveform equalization is preliminarily recorded on a disk medium and the waveform equalization to suppress an interference between bits of a read waveform by an adaptive type equalizer is performed. An error detector executes a training operation for adjusting an equalization amount of the adaptive type equalizer so as to minimize an error due to the interference between bits of the read waveform on the basis of the training pattern read out from the disk medium. A bit pattern detector detects a predetermined bit pattern "00" included in the training pattern and instructs the start of the training operation to the error detector by the detection of the first bit pattern "00". A counter counts the number of detection times of the bit pattern "00" by the bit pattern detector and instructs the end of the training operation to the error detector when the number of detection times reaches a predetermined value.