Patent ID: 6426844
Filing Date: 2002-07-30
Classification: G11B

Abstract:
Apparatus for demodulating a phase modulated servo signal in a disk file, said servo signal having a baseline, said apparatus comprising:at least one disk mounted for rotation about an axis and having at least one disk surface for storing data; means for writing at a predefined location of said disk surface a series of servo tracks of a predetermined high gain servo pattern, said high gain servo pattern producing a readback signal where the baseline is minimized; said predetermined high gain servo pattern including 3600 phase difference information within each servo track; said predetermined high gain servo pattern providing said readback signal having a predetermined high phase change for a predetermined radial displacement and said readback signal being at the baseline a predetermined small percent of time, whereby said readback signal does not flatten out at the baseline; means for detecting said servo tracks for identifying servo phase information; and means for demodulating a phase modulated servo signal.