Patent ID: 7630286

Claim:
An optical disk apparatus comprising: a binarizing circuit part for outputting a reference digital signal; and a digital PLL circuit part for outputting a write timing signal based on the reference digital signal, the write timing signal indicating a timing synchronizing with a digital clock signal having a predetermined frequency; wherein the digital PLL circuit part includes an edge detection circuit part for detecting a rise edge and a fall edge of the reference digital signal in time resolution units in which a single period of a reference clock signal is divided into N (N where is no less than 2) intervals and outputting an edge detection signal for each the single period in accordance with the detection result, a digital clock data generating part for generating digital clock data in accordance with a phase difference indicated in an input phase difference signal in each the single period, and a phase difference detection circuit part for detecting a phase difference between the reference digital clock signal and the digital clock signal and outputting the phase difference signal indicating the detected phase difference.