Patent ID: 7764580

Claim:
A demodulator for demodulating a digital signal from a wobble signal modulated by an HMW modulation scheme or an MSK modulation scheme, the demodulator comprising: enhancement means for enhancing a modulated frequency component included in the wobble signal and outputting an enhanced modulated frequency component; sync signal generation means for generating, from the wobble signal as a sync signal, a signal of a modulation frequency synchronized with the wobble signal when the wobble signal is modulated by the HMW modulation scheme or a signal of a reference carrier frequency synchronized with the wobble signal when the wobble signal is modulated by the MSK modulation scheme; multiplication means for multiplying the generated sync signal by the enhanced wobble signal for generating a non-integrated signal; hold means for determining a peak hold signal and a bottom hold signal of the non-integrated signal obtained by multiplication; and means for demodulating a digital signal from a result of a comparison of the determined peak hold signal and the determined bottom hold signal with a first preset threshold value and a second preset threshold value.