| 摘要 |
PURPOSE:To form information pits accurately by reading pit information right after recording and by controlling the peak value of light beam intensity in the recording. CONSTITUTION:The output of a readout level at which information is not written is sampled and threshold level signals stored in capacitors 36 and 39 are compared, so that a comparator 33 converts the pit information into pulses accurately at any time. A timing pulse generator 46 generates a timing pulse which synchronizes with the rise of a modulated signal from a modulating circuit 29, and this timing pulse drives a sawtooth wave generator 47 to generate a sawtooth wave synchronizing with the rise of the modulated signal. This sawtooth wave is sampled with the pit information and stored in a capacitor 49 through an analog gate 48 and an error signal which corrects output intensity during the recording of a semiconductor laser 21 by an error amplifier 50 is superposed, thereby exercising real-time control so that the peak value of the laser output intensity is held constant. |
