Patent ID: 8953426
Filing Date: 2015-02-10
Classification: G11B

Abstract:
1. An information reproducing apparatus in which one optical laser spot is formed on one recording track with respect to an information recording medium recording data on a plurality of adjacent recording tracks and the data is reproduced based on reflected light from the optical laser spot, the information reproducing apparatus comprising: a photodetector divided by a dividing line parallel to a recording track scanning direction into a first light-receiving section that receives reflected light of a center section of the recording track and a second light-receiving section that receives reflected light of a portion adjacent, in a radial direction of the information recording medium, with respect to the center section; a first adaptive equalization filter that performs waveform equalization of an output signal from the first light-receiving section; a second adaptive equalization filter that performs waveform equalization of an output signal from the second light-receiving section; and a data decoder that decodes reproduction data based on an output waveform from the first adaptive equalization filter and an output waveform from the second adaptive equalization filter, wherein the first adaptive equalization filter performs waveform equalization of an addition result of a waveform of an output signal from the first light-receiving section and an output waveform from the second adaptive equalization filter, and the data decoder performs binarization processing of an output waveform from the first adaptive equalization filter, and the information reproducing apparatus further comprising: a third adaptive equalization filter that outputs an ideal reproduction waveform based on a result of binarization processing by the data decoder and an addition result of a waveform of an output signal from the first light-receiving section and an output waveform from the second adaptive equalization filter; a first coefficient arithmetic unit that performs operation of a coefficient used in the first adaptive equalization filter based on a signal of error between an equalization target waveform obtained based on a result of binarization processing by the data decoder and an output waveform from the first adaptive equalization filter; and a second coefficient arithmetic unit that performs operation of a coefficient used in the second adaptive equalization filter based on a signal of error between an addition result of a waveform of an output signal from the first light-receiving section, and an output waveform from the second adaptive equalization filter and an output waveform from the third adaptive equalization filter.