SEMICONDUCTOR DEVICE AND OPTICAL DISK DRIVE

摘要

PROBLEM TO BE SOLVED: To prevent a decrease in decoding accuracy of a regenerative signal.SOLUTION: A semiconductor device includes: an analogue/digital conversion section for converting a regenerative signal of an optical disk into a digital signal; a waveform equalization section for equalizing the regenerative signal converted into the digital signal to desired characteristics; a Viterbi decoding section for performing Viterbi decoding to the equalized regenerative signal on the basis of a plurality of amplitude reference values 125; and an update section 108 for updating the amplitude reference value following the signal level of the equalized regenerative signal. When updating the amplitude reference value, the update section does not follow the equalized regenerative signal with a tolerance smaller a first threshold in a case where a tolerance between the signal level of the equalized regenerative signal and the amplitude reference value is smaller than the first threshold.