Disk drive estimating noise in a read signal based on an identified response at the input of an equalizer

摘要

A disk drive is disclosed comprising a head actuated over a disk, and control circuitry comprising a read channel comprising an analog filter and an equalizer. Data is read from the disk to generate a read signal, and the analog filter filters the read signal. The filtered read signal is sampled, and the read signal samples are input into the equalizer in order to equalize the read signal samples according to a target response. A response of the read channel based on the read signal samples input into the equalizer is identified to generate an identified response. Expected samples are generated based on the identified response, wherein the expected samples correspond to the data written to the disk, and an estimated noise sequence is estimated based on the expected samples and the read signal samples.

主权项

1. A disk drive comprising:
a disk; a head actuated over the disk; and control circuitry comprising a read channel comprising an analog filter and an equalizer, the control circuitry operable to:
write data to the disk;read the data from the disk to generate a read signal, wherein the analog filter is operable to filter the read signal to generate a filtered read signal;generate read signal samples in response to the filtered read signal, wherein the read signal samples are input into the equalizer in order to equalize the read signal samples into equalized samples according to a target response;identify a response of the read channel based on the read signal samples input into the equalizer to generate an identified response;generate expected samples based on the identified response, wherein the expected samples correspond to the data written to the disk; andgenerate an estimated noise sequence based on the expected samples and the read signal samples.