| 摘要 |
PURPOSE:To achieve a higher working efficiency eliminating prerotation, by detecting a reference mark attached to the circumference of a sample during the rotation for measurement with a photocell to detect and memorize the peak thereof, which is utilized for indexing an unbalanced angle. CONSTITUTION:A sample W is rotated with a belt 2 being driven by a motor 1 to detect a reference mark S attached to the circumference thereof with a photocell 3. The output of the photocell 3 is introduced into two successive inversive amplifiers 4a and 4b and after the polarity thereof is unified in a specified direction with a switch 5, it is divided in two to be inputted into a peak detection circuit 6 and a comparator 7. The output of the peak detection circuit 6 is inputted into a memory circuit 9 by closing a switch 8 during the rotation for measurement to be a reference voltage signal of the comparator 7. The signal thus obtained is utilized for indexing an unbalance angle thereafter. Thus, the mark S can be detected during no more than one rotation without requiring prerotation and moreover, indexing can be done within subsequent one rotation. |
