Patent ID: 7054238

Claim:
A signal shaping circuit for receiving an input of a returning light signal from an optical disc or a master optical disc on which a varied modulated signal obtained by varying a modulated signal with a predetermined variation pattern is recorded and for converting the returning light signal so as to generate a shaped signal, said signal shaping circuit characterized by comprising: signal length measurement means that measures a signal length of said returning light signal; signal level measurement means that measures a signal level of said returning light signal; shaped signal pattern generation means in which variation pattern information with regard to said predetermined variation pattern is stored therein in advance, which calculates and generates a shaped signal pattern from values of said signal length measured by said signal length measurement means and said signal level measured by said signal level measurement means and said variation pattern information; and shaped signal generation means that converts said returning light signal based on said shaped signal pattern generated by said shaped signal pattern generation means and generates the shaped signal.