| 摘要 |
<p>PURPOSE:To considerably improve the tracking phase deviation of tracking control which is performed with a pilot signal, by sampling and holding an average value of the tracking error signal and using this average value as a held value. CONSTITUTION:The average value obtained by averaging a tracking error signal 700 in a tracking error signal passage period longer than the holding period is sampled and held by a sampling and holding circuit 23, and this average value is used as the held value. Therefore, the level difference generated at a switching point (a) of a changeover switch 27 is considerably reduced. That is, even if a non-average signal is generated in the sampling section where compatible reproducing or recording and reproducing efficiency is bad, a synthesized output signal 800 approximating the essential tracking error signal is obtained because the tracking error signal in the signal passage period longer than the holding period is averaged to obtain the average value; and thus, tracking phase deviation is eliminated at the time of tracking control performed with the pilot signal.</p> |
