Equalizer for high density optical disc reproducing apparatus and equalizing method therefor

An equalizing method for a high density optical disc reproducing apparatus, comprising:

• transforming and outputting an input signal according to predetermined threshold levels;
• inverting and outputting a phase of a high frequency spectrum component of the transformed signal;
• increasing and outputting an amplitude of the high frequency spectrum component of the input signal;
• and
• adding the inverted signal with the amplitude-increased signal.

An equalizing method for a reproducing apparatus of a high density optical recording medium, the method comprising:

• detecting a difference component between a signal component of an input signal and a predetermined threshold level when the signal component of the input signal exceeds the predetermined threshold level;
• increasing amplitudes of high frequency spectrum components of the input signal and outputting low frequency spectrum components of the input signal without increasing Inter-Symbol Interference;
• and
• adaptively suppressing the increased amplitudes of the high frequency spectrum components by the difference component.

A reproducing apparatus for a high density optical recoding medium, comprising:

• detecting means, detecting a difference component between a signal component of an input signal and a predetermined threshold level when the signal component of the input signal exceeds the predetermined threshold level;
• amplitude increasing means, increasing and outputting amplitudes of high frequency components of the input signal and outputting lower frequency components of the input signal without increasing Inter-Symbol Interference;
• and
• amplitude controlling means, adaptively suppressing an amplitude of a high frequency component output from the amplitude increasing means, in response to the difference component, and reducing Inter-Symbol Interference of the output signal.