| 摘要 |
PURPOSE:To stabilize tracking servomechanism by detecting a specific high frequency component in an output signal and suppressing the gain of an amplifying means by using the high frequency component. CONSTITUTION:When the tracking servocontrol over an optical system is disordered owing to disturbance due to a shock to a reproducing device and a flaw, etc., on an information recording medium, a current flowing through a tracking-directional driving coil 13 which drives the optical system contains a frequency component much higher than a normal tracking servocontrol range. This high frequency component is extracted by a resistance 24 and a capacitor 25 and a voltage which turns on a transistor (TR) 19 is developed at a point A, so the conduction of a TR 15 turns on an FET 7 and the tracking servocontrol is turned off. Consequently, the optical system becomes stationary and the current flowing through the tracking-directional driving coil 13 does not have the high frequency component any more; and the tracking servocontrol is turned on and normal reproduction becomes possible, thus performing invariably stable tracking control.
|
