| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser beam output control circuit which can follow a complicated pulse shape at a high speed in a recording mode and can obtain a noise compression effect in loop control band in a reproduction mode. SOLUTION: In the recording mode, the outputs of voltage electric current control circuits 91 , 92 ,..., 9n generated by the control voltage held in a hold circuit is switched by a switching circuit 10. In reproduction mode, a reproduction power programmed voltage 52 switched by a switching circuit 51 for power programmed voltage is compared with the output of a current-voltage conversion circuit 3. A control voltage then outputted from a error amplifier 41 for reproduction/erasing is selected by the switching circuit 10, a light and an electric negative feedback loops in the reproduction mode are formed, and each light-emitting of a predetermined level is carried out. |
