Patent ID: 7301876
Filing Date: 2007-11-27
Classification: G11B

Abstract:
1. A multi-layered disc reproducing apparatus for reproducing information data recorded on a multi-layered disc comprising a plurality of recording layers laminated with each other in a direction of a normal line of said recording layers, in each of which an information data recording area for recording the information data and a control data recording area for recording control data to control an operation of recording and/or reproducing the information data are disposed on a same plane, the control data being recorded by a CAV (Constant Angular Velocity) method over a plurality of tracks in said control data recording area, the control data being recorded in only one of said recording layers, said multi-layered disc reproducing apparatus comprising: a detection signal outputting device for outputting a detection signal, which carries the control data in said control data record area, on the basis of a reflected light obtained by an irradiation of a reading light onto said control data recording area; a control data reproducing device for reproducing the control data on the basis of the detection signal outputted from said detection signal outputting device; and an information data reproduction controlling device for reproducing the information data recorded in said information data recording area on the basis of the reproduced control data, wherein said control data reproducing apparatus comprises: a low pass filter for extracting a control data signal based on the control data from the detection signal; and a control data decoder for generating the control data by the control data signal extracted by said low pass filter, wherein said low pass filter has a cut-off frequency, which is a double frequency of a repetition frequency of a longest pit carrying the control data, and an attenuation characteristic, which attenuates the detection signal from a standard level of said low pass filter by the cut-off frequency.