Abstract: An apparatus for reproducing information recorded on an optical disc which can favorably accomplish a time base correction for a read signal in a simple configuration. Also, the apparatus precisely removes jitter components produced when a driving signal is supplied to a spindle motor. The apparatus has a spindle motor for rotating an optical disc, a pickup for optically reading a recorded signal on the optical disc to generate a read signal corresponding to the recorded signal, and an A/D converter for digitizing the read signal to reproduced an encoded signal. The apparatus is provided with a controller for supplying the spindle motor with driving power. The controller has an unnecessary component removing filter for removing high frequency components from the motor driving power.

Abstract: A data reproduction apparatus includes a system controller for monitoring an amount of data in a memory and a linear velocity detected by a linear velocity detecting section, controlling a DC signal output from a DC signal generating section to a disk motor driving section as a drive signal, and controlling interruption and resumption of writing of information to the memory so as to prevent the memory from overflowing. The output DC signal of the DC signal generating section is controlled such that a velocity at which information is written to the memory means is higher than a velocity at which information is read therefrom so as to always store information in the memory, and the linear velocity detected by the linear velocity detecting section becomes close to a preset linear velocity, and the rotation of the disk is controlled by the DC signal. The power consumption required for controlling the rotation of the disk can thus be reduced.

Abstract: Address information indicative of a certain recording/reproduction position is recorded twice (first address, second address) in an optical disk. Second phase control means makes sampling timings for digitizing the first address have optimal phases. Third phase control means makes sampling timings for digitizing the second address have optimal phases. The second and third phase control means are formed with different circuits, respectively.

Abstract: An information reproducing apparatus is disclosed that comprises measuring means for measuring the intensity of a jitter of a signal read from an information record medium such as a disc, storing means for temporarily storing reproduced information at a first transfer rate, means for reading information stored in the storing means at a second transfer rate that is smaller than the first transfer rate, wherein the maximum speed of the information record medium is set up corresponding to the intensity of the jitter measured by the measuring means.

Abstract: A disk recording or playback device comprises a pickup movable along the rear surface of a disk, a motor for moving the pickup, arithmetic means for calculating the position of the pickup on the disk, and timer means for measuring the time taken for the movement of the pickup. Predetermined for controlling the operation of the pickup are a specified distance L1 the pickup is to be moved, and a standard period of time T1 taken for the pickup to move the distance L1. The pickup is moved the specified distance L1 by energizing the motor, and the time taken for the movement and measured by the timer means is compared with the standard time T1. The voltage to be supplied to the motor is calculated from the result of comparison. When the measured time is approximate to the standard time T1, the value of the voltage for the motor is temporarily stored in a nonvolatile memory.