| 摘要 |
PURPOSE:To attain a stable servo pull-in action by using a means to measure the resetting time of a prescribed section in a reset mode of an actuator and a means to change the characteristics of an equalizer in response to the measured resetting time. CONSTITUTION:The resetting time of an actuator 8 varies in response to the temperature change of a pickup unit. Thus, a KI control circuit 17 controls the integration time constant KI that decides the characteristics of a digital equalizer 5 in response to the change of a reference level Vref. The DC gain of the equalizer 5 can be increased with increase of the constant KI. Therefore, the constant KI is increased by the circuit 17 according to the reference level Vref when said level Vref is increased (when the temperature of the pickup unit drops). Thus the DC gain of the equalizer 5 is increased and it is possible to avoid such a trouble where the servo pull-in mode is released before the actuator 8 reaches a set oscillating position.
|
