A signal processing device for an optical information reproducing apparatus is provided. The reproducing apparatus reproduces information using a light beam from an information recording medium having tracks in which the information is recorded in such a manner that optically readable marks are digitally and selectively formed with a discrete length which is a substantially integral multiple of a basic period T. the device includes: an optical pickup head device outputting a signal mainly containing information recorded at a desired position; an equalizer receiving the signal and emphasizing an amplitude of a high frequency component of the signal relative to a low frequency component of the signal in accordance with a coefficient capable of being arbitrarily set; a clock signal generator generating a clock signal representing a timing synchronized with an edge of digital information recorded as marks or spaces on the information recording medium; an index processor receiving an output signal from the equalizer to calculate an index; and a signal processing circuit outputting a control signal for controlling the coefficient in the equalizer based on the index.
Signal processing device for an optical information reproducing apparatus