Optical information recording and regenerating apparatus which regulates the amplitude of a regenerated signal

摘要

An optical information recording and regenerating apparatus for optically recording and regenerating information to and from a medium having a regenerating system which includes an AGC circuit consisting of a gain-variable amplifier for controlling the amplitude of a regenerated signal, which is obtained when regenerating information, to a predetermined value; a differential circuit for differentiating an output signal of the AGC circuit; and a peak detecting circuit for detecting the peak value of an output of the differential circuit. The AGC circuit controls gain in accordance with the output of the peak detecting circuit so that the peak value of a differential signal of a regenerated signal in a preformat area, wherein information has been embossed in a medium beforehand, becomes constant.