| 摘要 |
PURPOSE:To rapidly output the required object recording deletion power from a semiconductor laser by superimposing the reproduction error signal just before the reproduction on a recording reference signal, thereby correcting the recording reference signal. CONSTITUTION:At a recording mode, a power detection signal Vmw following the power of a semiconductor laser 54 is outputted from a recording signal detection circuit, and a reproduction detection signal Vmr at the reproduction is held during the recording mode. Then, the feedback control is performed by using both signals while taking an APC control signal as 'H'. The peak hold is released with the stable output of the laser 54. At the reproduction mode, the reproduction power of the laser 54 is outputted by the feedback control using a reproduction reference signal Vrr and a detection signal Vmr, and a recording detection signal Vmw and a deletion detection signal Vme are supplied. The laser output is increased according to the reference signal Vrw. The feedback control is finished while taking the APC signal as 'L'. Further, a reproduction error signal is calculated by operation amplifiers 78 and 80, and the temperature correction of a reproduction error signal A78 (Vrr-Vmr) is performed by overlapping the recording reference signal Vrw or a deletion reference signal Vre through an operation amplifier 96. |
