US Patent 7680009 Optical disc reproducing apparatus performing equalizer adjustment

An optical disc reproducing apparatus has a function of setting a cutoff frequency and a boost amount of a read out signal from an optical disc and performing equalizer adjustment, and includes a system controller for searching for an optimal jitter value by simultaneously changing a cutoff frequency and a boost amount to thereby set positions of jitter measuring points determined on a coordinate plane whose abscissas represent cutoff frequencies and whose ordinates represent boost amounts, and by moving the measuring points.