In situ offset correction for position error signal

摘要

The present invention generally provides a method and system for correcting for offset in a position error signal. In accordance with one embodiment of the invention, the readback signals dependent upon a read sensitivity profile of a read head are generated by moving the read head over a correction track. Using the readback signals, a characteristic value of the read sensitivity profile is determined. The characteristic value of the read sensitivity profile is used to adjust raw position error signals generated using the read head. The characteristic value may, for example, be determined from one or more data points from a cumulative sum data set. In accordance with another embodiment of the invention, a storage device is provided. The storage device includes a read head and a storage medium which includes a correction track and which is mounted to allow relative movement between the read head and the storage medium. The storage device further includes a servo control system. The servo control system generates readback signals dependent upon a read sensitivity profile of the read head by incrementally moving the read head over the correction track and determines a characteristic value of the read sensitivity profile using the readback signals. The servo control system further generates the raw position error signal by demodulating induced signals in the read head and uses the characteristic value of the read sensitivity profile to adjust the raw position error signal.