DEMODULATION CIRCUIT, OPTICAL DISK DRIVE, AND SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a demodulation circuit which normally demodulates a recording auxiliary signal even if the S/N ratio of a wobble signal is greatly deteriorated. SOLUTION: The device is provided with: a waveform converting circuit 50a for converting the waveform of the wobble signal outputted by a high frequency amplifier 15; a reference value generating circuit 40a for generating a reference value necessary for viterbi decoding from an output of the waveform converting circuit 50a; a clock generating circuit 30a for generating a clock CLK on the basis of an output of the reference value generating circuit 40a and the output of the waveform converting circuit 50a; a sampling circuit 53a for sampling the output of the waveform converting circuit 50a in synchronization with the CLK; and a viterbi decoder 31a for decoding the recording auxiliary signal by using the reference value and a sampled signal outputted by the reference value generating circuit 40a. COPYRIGHT: (C)2004,JPO