| 摘要 |
PURPOSE: A servo method for an eccentric compression and a servo device using the same, are provided to supply addition signals of an eccentric compression signal and a driving signal of a tracking actuator to the tracking actuator in a feed-forward type, to extend a loop gain. CONSTITUTION: A disk(20) is loaded to initialize a system. Whether a focus servo(28) is driven is discriminated. If so, a spindle servo(36) is driven to rotate the disk(20), and a sled servo is driven. The first read sector number is set up as a reference sector. If a reference sector is set up, a tracking signal according to eccentricity is detected, and an eccentric degree is calculated. A digital signal processor/PLL(Phase Locked Loop)(24) converts a calculated eccentric compression feed-forward control signal according to the first rotative phase into an electric signal, and stores the converted signal in a memory(26). The focus servo(28) is turned off and the spindle servo(36) is driven, to rotate the disk(20). If a disk play key is inputted, a normal play is inputted. A phase with the reference sector is calculated using a regenerated sector signal. A feed-forward controller(100 loads eccentric compression information generated in the calculated phase from the memory(26) as a control signal, and an addition signal of the control signal and a feedback signal to a tracking actuator.
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