Patent ID: 8116023

Claim:
A disk drive comprising: a disk comprising a plurality of servo sectors defining a plurality of servo tracks, and a head actuated radially over the disk for generating a read signal, wherein: each servo sector comprises a preamble comprising a first end and a second end; each servo sector comprises a servo sync mark after the second end of the preamble; the servo tracks form a plurality of servo zones; a servo data rate of the servo sectors in a first servo zone is different than a servo data rate of the servo sectors in a second servo zone; the first end of the preambles in the servo sectors are aligned along a radius of the disk across at least the first servo zone and the second servo zone; the disk drive further comprising control circuitry operable to: generate a servo clock; open a servo gate window in response to the servo clock when the head approaches one of the servo sectors; when the head transitions between the first servo zone and the second servo zone, adjust the servo gate window; and demodulate the servo sector, wherein the control circuitry is further operable to adjust an end of the servo gate window.