| 摘要 |
PURPOSE:To always attain highly accurate track servo even if a deviation between sectors is large by previously storing a track deviation due to eccentricity to execute track servo. CONSTITUTION:Reproduced signals from a head 1 are inputted to a comparator 4 through BPFs 2a, 2b having respective frequency f1, f2 and peak detecting and holding circuits 3a, 3b and a deviation of each servo signal is detected. Its deviation signal is inputted to a memory 12 through A/D converters 11, 16. On the other hand, signals from the BPFs 2a, 2b are inputted to an address counter 13 and its address value is inputted to the memory 12. A signal for increasing an address value by one step is inputted from a terminal 14 to the memory 12 through a switch 15 and track deviations detected by servo signals are written in respective addresses of the memory 12. When a switch 15 is turned on after completing the writing, a signal read out from the memory 12 is added to a signal outputted from the circuit 4 by an adder 17 and the added signal is sent to an actuator 6 to execute track servo.
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