| 摘要 |
PURPOSE:To decrease an outside fitting, to minimize a circuit scale and to implement an IC by using a switched capacitor filter SCF in order to give a necessary amplitude and a phase characteristic to a focus error signal and a tracking error signal. CONSTITUTION:SCF 8 and 9 raise a low area gain to a necessary extent and generates a phase margin. The output of the SCF 8 controls so that an optical head 2 can form a focus at the signal surface of a disk 1 through a focus driving circuit 11 and the output of the SCF 9 controls so that the optical head 2 can follow the signal track of the disk 1 through a tracking driving circuit 12. Since the optical head 2 follows only to the minute scope, the output of the tracking driving circuit 12 is inputted to an SCF 10, the output controls a feeding motor 3 through a feeding motor driving circuit 13 and the optical head 2 is followed to the slow action of a signal track. Thus, when an IC implementation is executed, outside fitting parts are not may and the circuit scale can be minimized.
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