| 摘要 |
<p>PURPOSE:To eliminate the deterioration in tracking precision caused by temperature variation and the change with lapse of time by providing a means which sets a second reference signal of a tracking control means into an equivalent value of a first reference signal. CONSTITUTION:ATF error signals are converted into digital data by an A/D converter 311 and the converted error data are processed based on ATF-REF voltage data which correspond to a reference voltage VR generated by a microcomputer. However, there is a possibility in which two voltages deviate from each other due to temperature variation and the secular change. In that case, VR from a reference voltage generation section 310 is converted into digital signals by the converter 311 of the microcomputer side and the converted data are used as ATF-REF data.</p> |
