Abstract: A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk is provided. The method includes the steps of counting mirror signals generated for every revolution of the disk recording medium, where each mirror signal corresponds to one of the tracks radially arranged on the disk recording medium; moving a pickup until the counted number of mirror signals is equal to a predetermined number of tracks required for the pickup to pass to reach a target track. The method further includes the steps of checking respective intervals of successive mirror signals; determining if there is a difference in length between intervals of two successive mirror signals; and executing a correction mode by adding or subtracting a correction value to the counted number of mirror signals if there is a difference in length between intervals of two successive mirror signals.

Abstract: A disk is rotated by a spindle motor. The spindle motor is controlled such that the disk is rotated at a constant linear velocity (CLV) against a recording head. A signal read by a reproducing head is stored in a time-axis expansion and compression memory. When a signal is written into the time-axis expansion and compression memory and when a signal is read therefrom, the time axis of a signal read by the reproducing head is compressed or expanded according to the track position of the reproducing head so as to match the time axis obtained at a constant linear velocity.

Abstract: A method for reducing the travel time for an optical pick-up and an apparatus thereof are provided to precisely control the tracking of said optical pick-up. The method comprises the steps of: (i) detecting the number of revolutions of the optical disc to determine the number of track-jumping signals produced in a unit time due to the rotation of the optical disc; and (ii) adding the number of track-jumping signals obtained in step(i) to the number of track-jumping signals detected in a unit time by the pick-up controller in the case that the optical pick-up moves outwardly, and subtracting the number of track-jumping signals obtained in step(i) from the number of track-jumping signals detected in a unit time by the pick-up controller in the case that the optical pick-up moves inwardly.

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: An apparatus for reproducing a multiple layer disk, which comprising a plurality of layers each having an information record surface on which record information is recorded, is provided with: a read device for reading the record information from each of the layers; a reproduction process device for applying a predetermined reproduction process to the record information read by the read device in accordance with a reproduction process parameter, which is set therein and which comprises at least one of a gain value and an equalizer value, to thereby output a reproduction information signal; a drive device for driving the read device to jump from one reading state for reading one of the layers to another reading state for reading another of the layers; a memory for storing a plurality of reproduction process parameters corresponding to the layers in advance of reproduction; and a set device for reading out one of the stored reproduction process parameters, corresponding to another of the layers as a destination

Abstract: A disc apparatus includes a micro-computer. The micro-computer causes a pickup to move to a predetermined position. A track pitch is calculated from a distance over which the pickup has moved and a number of tracks detected during the movement thereof over that distance. In response to a track jump command, tracks to be jumped over are determined in number by the distance from a center of a disc to a current position, a distance from the center of the disc to a target position, and a track pitch measured.