| 摘要 |
PURPOSE:To realize matching of rectangular sectional views with a high accuracy by differentiating the signal sent from two detector positions, obtaining a time or distance from the reference point and detecting rotation error of rectangular beam from a difference of times or distances. CONSTITUTION:A signal sent from a detector 12 is amplified 13 and is then differentiated 14. A power supply 15 of deflector 9 supplies a deflection voltage which moves a rectangular beam on the detector 12 along the X axis. A D/A converter which forms this power supply 15 operates with the reference clock and this rference clock is sent to a gate circuit 16. To this circuit 16, an output of the circuit 14 is supplied as the differentiated signal. Therefore, the gate opens by the deflection start signal and closes by the signal sent from the circuit 14. The clock pulse is sent to a counter 18 through this circuit 16 and the number of pulses while the gate is opened is counted. An output of this counter 18 is sent to an arithmetic operation circuit 19, a difference between the values obtained by rectangular beam scanning of two times can be obtained and thereby the rotation error of rectangular beam can be displayed 20. |
