| 摘要 |
A reading circuit in an optical disk drive is described. The reading circuit is of the type which transforms an analog read-out signal obtained by optically reading a disk to digital data. The reading circuit includes a differentiator for differentiating the read-out signal to generate a differentiated signal. Also included is a zero-level detector for generating a rectangular signal by detecting positive and negative levels of the differentiated signal. The reading circuit also includes a pit detecting circuit generating a pit detecting signal by comparing the read-out signal with a fixed reference voltage. The pit detecting signal indicates the period of the presence of the pit in the read-out signal. Also included is a multiplying circuit to generate an AND signal by multiplying the rectangular signal and the pit detecting signal. Finally an encoder is included for generating a rectangular encode signal of the recorded information in response to the AND signal. |
