| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase comparison device capable of accurately detecting a variation amount with respect to the original phase of an extracted wobble signal caused by influence of cross-talk from adjoining groove tracks. SOLUTION: The phase comparison device PD comparing prepits with a wobbling signal of an information recording device S with respect to an optical disk which has grove tracks wobbled by a wobble signal and land tracks as guide tracks to guide a recording beam, and has prepits formed on the land tracks with a specified phase relation to the wobbling signal but not formed on the land tracks adjacent to a same straight line in the direction of the radius, is provided with a wobble signal extracting means 15 for extracting the wobble signal, a prepit detecting means 13, a periodic signal generating means for generating a periodic signal synchronizing with the extracted wobble signal and monotonously increasing for a periodic period corresponding to a specified frequency, and a holding means for latching the amplitude level of the periodic signal at the timing of detecting the prepits. |
