Patent ID: 6680887
Filing Date: 2004-01-20
Classification: G11B,H03L

Abstract:
An optical disk apparatus for optically reproducing information recorded on an information carrier by an optical beam emitted by a light source, the optical disk apparatus comprising:a converging section for directing the optical beam to the information carrier in a converged state; a light detection section for generating a reproduction signal corresponding to the optical beam reflected by or transmitted through the information carrier; a waveform equalization section for varying a frequency characteristic of the reproduction signal generated by the light detection section; a jitter measuring section for measuring a jitter of a signal output from the waveform equalization section; and a minimum jitter value searching section for determining a minimum value of the jitter in an initial area of an X-Y plane defined by a variable x and a variable y which can vary the jitter measured by the jitter measuring section; wherein: the minimum jitter value searching section divides the initial area into a plurality of first divided areas having an identical shape to each other, each of which has a respective first jitter measuring point at the center of gravity thereof; and performs a search operation to find one of the plurality of first divided areas which has the first jitter measuring point at which a minimum jitter is measured among the first jitter measuring points, and the minimum jitter value searching section divides the first divided area, having the first jitter measuring point at which the jitter is minimum, obtained by the search operation into a plurality of second divided areas having an identical shape to each other, each of which has a respective second jitter measuring point at the center of gravity thereof; performs a search operation to find one of the plurality of second divided areas which has the second jitter measuring point at which a minimum jitter is measured among the second jitter measuring points; and determines an optimum combination of the variable x and the variable y which corresponds to the second divided area, having the second jitter measuring point at which the jitter is minimum found by the search operation.