Abstract: An equalizer for a high density optical disc reproducing apparatus and an equalizing method therefore are provided. The equalizer includes: a non-linear transformer, which transforms an input signal according to predetermined threshold levels; a cosine transform filter, which inverts phases of high frequency spectrum components of an output signal of the non-linear transformer; a high boost filter, which increases amplitudes of high frequency spectrum components of the input signal; and an adder, which adds an output signal of the cosine transform filter with an output signal of the high boost filter. Therefore, the equalizer can increase recording density of the optical disc in the high density optical disc reproducing apparatus and accordingly increase recording amount of information, by reducing inter-signal interference (ISI) and increasing a signal-to-noise ratio in the output signal of the equalizer. Also, the equalizer has a simple configuration.

Abstract: An apparatus for detecting wobble information of an optical disc and a method thereof are disclosed. The apparatus comprises an eliminator for outputting a second harmonic signal by eliminating subharmonic from an input wobble signal. A detector is provided for generating a cosine signal and a sine signal having a phase identical to the second harmonic signal, and detecting a phase difference of the second harmonic signal the generated signals. A compensator is provided for counting the phase difference and compensating the phase difference by shifting a phase of the cosine signal and the sine signal according to the counted value. Also, a signal output unit is provided for outputting a detection signal by multiplying the compensated cosine signal and the second harmonic signal, integrating the multiplied signal, and discriminating a signal. Accordingly, the phase error and the errors are minimized. Also, the detection accuracy increases, and the performance of detecting the saw-tooth wobble is improved.

Abstract: An equalizer for a high density optical disc reproducing apparatus and an equalizing method therefore are provided. The equalizer includes: a non-linear transformer, which transforms an input signal according to predetermined threshold levels; a cosine transform filter, which inverts phases of high frequency spectrum components of an output signal of the non-linear transformer; a high boost filter, which increases amplitudes of high frequency spectrum components of the input signal; and an adder, which adds an output signal of the cosine transform filter with an output signal of the high boost filter. Therefore, the equalizer can increase recording density of the optical disc in the high density optical disc reproducing apparatus and accordingly increase recording amount of information, by reducing inter-signal interference (ISI) and increasing a signal-to-noise ratio in the output signal of the equalizer. Also, the equalizer has a simple configuration.