Waveform equalizer for obtaining a corrected signal and apparatus for reproducing information

Abstract

The waveform equalizer () for obtaining a corrected signal S' by performing a waveform equalization to a read signal S read out from an information carrier (). The waveform equalizer () has a first filter () able to perform a filtering process to said read signal S, and an amplitude limiting means () able to obtain an amplitude limited read signal SLIM by limiting an amplitude level of said read signal S by a predetermined amplitude limitation value. A second filter () is provided which is able to perform a filtering process to said amplitude limited read signal SLIM. Further, an adder () is present which is able to add the signals obtained by performing the filtering process by each of said first () and second filters (), able to generate an addition result as said corrected read signal S′. The signal frequency response of said waveform equalizer () to signals having an amplitude smaller than said predetermined amplitude limitation value, has a notch in a first frequency region from zero to a frequency at which the signal frequency response is at a maximum amplitude. The apparatus for reproducing information recorded on an information carrier (), having the waveform equalizer () is able to read the information with a higher S/N ratio and a lower data jitter. As a result the information reproducing apparatus can be applied for a higher bit density and at the same time having a acceptable S/N ratio and data jitter.