| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to always detect pit and wobbling signals with high reliability irrespectively of the presence or absence of a recording mark on a groove by detecting the pit by offsetting a light spot on the groove at the time of detecting pits formed at predetermined intervals in an area between grooves. SOLUTION: By comparing a DTD signal TVE, on which an offset caused by a disk tilt is hardly gotten, with a pit elimination signal, and detecting the offset getting on a push-pull signal through a 1st low-pass filter 13a through which low-frequency components such as disk tilt can pass although the components are much lower than a tracking control frequency band, an offset of a pit elimination signal S2 is eliminated by a 3rd adding circuit 4d. Next, through a 2nd low-pass filter 13b, a tracking error signal S1 is obtained which has little meander due to a pit influence and little offset due to a disk tilt etc., the accuracy is further improved by eliminating the influence of the meander by pit from DPD signal TXE by a similar method.
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