| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylinder servo circuit for recording disk device capable of sufficiently coping with the high speed of an optical disk. SOLUTION: An eccentricity measuring instrument 36 totals the x component qcos(n) and the y component qsin(n) of a position error signal (q) to be measured each sector through which a head passes over one revolution of a disk to calculate total values (a), (b). An eccentricity correction value calculator 34 setes a waveform of u(θ)=Acos(θ)+Bsin(θ) based on the total values (a), (b). Since this waveform expresses deviations in the radial direction of the recording cylinder of the eccentric circle of a head locus with respect to the recording cylinder on the disk, a head to be driven in the radial direction of the recording cylinder based on this waveform draws a locus along the recording cylinder. When a feedback control is applied to the head, the head is made to follow up the recording cylinder.
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