| 摘要 |
<p>An operating circuit determines a push-pull signal Ps corresponding to the difference of output signals from two light receiving regions in the light receiving part of an optical pickup. In a prepit detecting circuit, a prepit peak value detecting circuit detects the peak value of the push-pull signal Ps, a BPF circuit extracts a wobble signal component, a wobble peak value detecting circuit detects its peak value, a voltage divider divides the difference between the peak value of the signal Ps and the peak value of the wobble signal component, and the divided voltage is inputted, as a slice level, to a prepit comparator (25) where the push-pull signal Ps is binarized to output a prepit signal SLPP.</p> |
