Abstract: A playback apparatus is disclosed for reproducing information data and sync data recorded sequentially in the sectors along tracks of a recording medium, in which a read unit generates a reproduced signal by reading the information data and the sync data, an AC coupling unit generates a corrected reproduced signal by selecting one of a first time constant and a second time constant larger than the first time constant and AC-coupling it to the reproduced signal, a detection unit outputs a detection signal indicating a timing for the read unit to read the sync data, a control unit controls the AC coupling unit in such a manner as to select the first time constant during the period from a first timing determined on the basis of the detection signal to a second timing a predetermined after the first timing and to select the second time constant at the second timing, a binary unit digitizes the corrected reproduced signal and generates a binary corrected reproduced signal, and a demodulator demodulates the informa

Abstract: A seek control apparatus for an optical disc recording/reproducing system controls the seeking movement of a head device adapted for recording/reproducing information signals on or from an optical disc as far as a desired position on a recording surface of the optical disc. The apparatus includes a current position detection unit for detecting the current recording/reproducing track position of a head device on a recording surface of a disc-shaped recording medium, a target value outputting unit for outputting a value changed as a second power of the time as the movement target position data from the current track position as far as an object track position, and a comparator unit supplied with an output signal from the current position detection unit and an output signal from the target value outputting unit and adapted for comparing the two output signals to each other. Seek control of the head device is performed on the basis of an output signal from the comparator unit.