| 摘要 |
PURPOSE:To eject a defective disk automatically when the count value exceeds a prescribed level after counting the frequencies where the phase control amount or the focus error due to a servo system exceeds a reference level. CONSTITUTION:The warp of a disk is detected by the amount of a focus error (v), and this error (v) is compared with the reference value V by a comparator 26. Therefore, a detection signal is delivered from the comparator 26 when the disk warp exceeds the reference level. Then the output of comparison is supplied to a sampling circuit 28 and sampled for each application of a sampling clock phi. The sampling outputs are counted by a counter 30. When this count value exceeds the prescribed value N, a desired alarm circuit 32 and an end control circuit 34 are actuated to perform an alarming action or finish the actuation. Thus a defective disk is informed to a user by means of a sound or a lamp display. The end of actuation means the discontinuation of a player operation, the ejection of disks and the break of a power supply. |
