| 摘要 |
PURPOSE:To detect an error of the track fluctuation, by receiving the reflected light given from a recording medium at a detector which is divided by a dividing line parallel to a track and passing through the optical axis of an optical system and feeding back the amplitude difference of a reproduced signal to the optical system. CONSTITUTION:The optical axis of the reflected light given from a rotary disk 8 is bent via a polarizer 10 and a beam splitter 5', and the reflected light is received at a light detector 6' which is divided by a dividing line passing through the optical axis of an optical system. The information signals read out of the detector 6' are filtered 11 and 12, and the output of addition 13 of these signals is used as an information reproducing signal 14. On the other hand, the outputs of the filters 11 and 12 are fed to absolute value circuits 15 and 16 to be filtered 17 and 18 for rectification. Thus an envelope curve is obtained, and the output of a differential amplifier 19 set between envelope curves is fed back to a polarizer 10 in the form of a track error signal. |
