Abstract: 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.

Abstract: An optical information recording and reproducing apparatus includes a random information generating section for generating predetermined random information. A recording information generating section generates recording information on the basis of non-DC-free information and the predetermined random information. A synchronization sensing section senses a synchronization information. A recording section records the recording information in the recording area of a recording medium, on the basis of the synchronization information. A reproducing section reproduces the recording information recorded by the recording section.

Abstract: A fine access method for an optical disk drive uses a multi-track jump method to cover a wide range of several hundred tracks at a high speed. According to the present invention, one-shot acceleration and deceleration pulses with a short width are sent to an actuator head immediately after every one-half track pitch travel of the actuator head. The actuator head is accelerated when the travel time for one-half track pitch is slower than a first reference time and it is decelerated when the travel time is faster than a second reference time. When the travel time is between the first and second reference times, no pulse is sent to the actuator head. Thus the velocity of the actuator head is compensated and maintained within a specified range of deviation for a whole long range of jumping a plurality of tracks.