| 摘要 |
PURPOSE:To make it difficult that tracking control is disturbed by a defect of an information recording carrier, by switching the time constant of a high-pass filter to a small value when a defect is detected in a reproduced part of the information recording carrier and cancelling quickly a speed error just after detection when noise is mixed into a control signal just before detection because of delay of defect detection to generate the speed error in an actuator. CONSTITUTION:If a defect detection signal is outputted when a defective part of an information recording carrier 1 is tracked, a changeover switch 8 switches the signal to be inputted to a high-pass filter 12 from the error signal outputted from an error detecting circuit 5 to the output signal from a low-pass filter 11 and switches the time constant of the high-pass filter 12 to a small value. Thus, even if an impulsive noise remains because of delay of defect detection, the speed error due to this noise is canceled just after detection to stabilize tracking. |
