Patent ID: 7680009

Claim:
An optical disc reproducing apparatus having a function of setting a cutoff frequency and a boost amount of a read out signal from an optical disc and performing equalizer adjustment, comprising: an optical pickup for generating the read out signal; a system controller to search an optimal jitter by simultaneously changing cutoff frequency and the boost amount thereby performing the equalizer adjustment, the system controller comprising: the optical pickup setting unit for causing an optical pickup to seek a predetermined address on the optical disc to measure jitter and for setting the optical pickup in a pause state; a measuring point setting unit to sequentially set at least two points, and to measure a jitter at each point, the two points being located on a coordinate plane whose abscissa represents cutoff frequencies and whose ordinate represents boost amounts, wherein one of the two points is set as a reference search point and the other one of the two points is set at a position displaced by a set value from the reference search point; a first jitter bottom judging unit to check whether jitter values at the two points satisfy a filtering condition, wherein when the jitter values at the two points fail to satisfy the filtering condition, the two points are judged to be outside of a bottom of a jitter coordinate space and the two points are updated to different locations, wherein when the jitter values at the two points satisfy the filtering condition and when a difference in a jitter value between the two points is within a predetermined range, the two points are judged to be at the bottom of the jitter coordinate space; a first adjustment value setting unit to set an equalizer adjustment value when the two points are judged to be placed at the bottom of the jitter coordinate space, wherein the equalizer adjustment value is one of the jitter values having a value less than or equal to the other one; a measuring point moving unit configured to update the two points when the two points fail to satisfy the filtering condition, and configured to update one of the two points when the difference in the jitter value judges that the two points are outside the predetermined range, wherein the one of the two points having a larger jitter value is updated by moving to a different point by a set value; a second jitter bottom judging unit to judge that the point being moved and the other point are placed at the bottom of the jitter coordinate space when a difference in a jitter value between a jitter at the point being moved and the jitter at the other point is within the predetermined range; and a second adjustment value setting unit to set the equalizer adjustment value when the point being moved and the other point are judged to be placed at the bottom of the jitter coordinate space, wherein the equalizer adjustment value is one of the jitter values having a value less than or equal to the other one.