Optical recording/reproducing apparatus

摘要

An optical recording/reproducing apparatus includes a monitor sensor for sensing the amount of emission from a laser diode or optical head. The output of the monitor sensor is routed through a non-inverting wide-band amplifier and an inverting amplifier to an envelope detector. The envelope detector detects peak values out of the input signal and delivers them to a current amplifier via an amplifier and a comparator. The current amplifier feeds a current corresponding to the input to the laser diode. This current corresponds to erasing power. The apparatus senses the emission conditions of the laser diode between the start and end of the recording operation so as to cause erasing power to constantly coincide with a reference value.