Patent ID: 6687079
Filing Date: 2004-02-03
Classification: G11B

Abstract:
A method for providing a position information signal for a hard disk drive, comprising:a) providing a disk that has a plurality of tracks, each of said plurality of tracks having a track centerline and a plurality of servo fields, each servo field having an A burst, a B burst, a C burst and a D burst, the A burst and the B burst have a common boundary located at the track centerline and the C burst and the D burst have a common boundary, each of said A, B, C and D bursts providing a corresponding servo burst value; b) aligning a read element over the track centerline; c) sensing the A, B, C and D bursts; d) generating an upper threshold and a lower threshold based on said A, B, C and D servo burst values; e) generating Aâ€², Bâ€², Câ€² and Dâ€² servo burst values based on the upper and lower thresholds; f) generating a position error signal based on the Aâ€², Bâ€², Câ€² and Dâ€² servo burst values and, g) storing said position error signal in a memory device.