| 摘要 |
PURPOSE:To decrease the difference of focus offset between a preformat part and a data part and to attain a data writing state by using a means which suppresses the offset change of the focus error signal produced by the change of the light emitting output. CONSTITUTION:The offset control voltage Voc divided by a variable resistance VR with its both ends connected to power supplies +Vcc and -Vcc respectively is applied to the reverse input terminal of a reverse amplifier 22 via an analog switch 25. The ON/OFF of the switch 25 is controlled by the write gate signal *WG which is set at a low level with the write light emitting output.
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