Patent ID: 6894957
Filing Date: 2005-05-17
Classification: G11B

Abstract:
1. An optical disk reproducing apparatus comprising: a signal extracting section configured to emit light on to a track of a disk having a track shape of concentric tracks or a spiral track on which information has been recorded during rotation of the disk, to extract the information by receiving the light which is reflected from the track or is passed through the track, to convert the information to an electric signal, and to output the electric signal; an information signal generating circuit configured to generate a signal including the information which is recorded on the disk and a tracking error signal which shows a deviation of a relative position in the radial direction of the disk between the light which the signal extracting section emits and the track from the signal extracting section; a tracking moving section configured to move the position of the light emitted from the signal extracting section in the radial direction of the disk; a tracking control circuit configured to generate a tracking control signal in response to the tracking error signal such that the position of the emitted light from the signal extracting section is maintained on the track; an eccentricity signal generating circuit configured to generate an eccentricity showing a position deviation between a center point of the track shape of the disk and a rotation center point of the disk on the basis of the output of the information signal generating circuit; and a tracking correcting circuit configured to substantially add the output of the eccentricity signal generating circuit to the output of the tracking control circuit to drive and control the tracking moving section on the basis of the added output; wherein the eccentricity signal generating circuit comprises: a reading-out speed detecting circuit configured to detect the reading-out speed of the information from the output of the information signal generating circuit, and a band-pass filter configured to extract the component which is near the rotation frequency of the disk within the range of the change in the reading-out speed of the information from the output of the reading-out speed detecting circuit to output the eccentricity signal.