Patent ID: 8917475

Claim:
A disk drive comprising: a disk comprising servo data; a head actuated over the disk; and control circuitry configured to: estimate an offset r 0 representing a difference between an axial rotation of the disk and an axial rotation of the servo data; generate radial dependent timing compensation values in response to the estimated r 0 ; generate a phase error in response to the servo data; generate a control signal in response to the phase error and the radial dependent timing compensation values; and adjust a frequency of an oscillator in response to the control signal, wherein the control circuitry is further configured to generate the radial dependent timing compensation values according to: r 0 r s ⁢ sin ⁡ ( θ + φ ⁡ ( r s ) ) where: r s represents a radial location of the head; θ represents the rotation angle of the disk; and φ(r s ) represents a phase offset of the radial dependent timing compensation values based on the radial location of the head.