| 摘要 |
PURPOSE:To make it possible to perform measurement at a correct position all the time and to eliminate the effect of the setting angle of a detector, by determining the measuring position based on the output signal of a converting means, which converts the signal corresponding to a scanning angle to a signal corresponding to the position, and taking out and computing the output signal of the detector. CONSTITUTION:Based on a synchronization signal e2 from a synchronization signal generator 2, a scanning angle signal generator 3 generates a square wave signal e3 corresponding to a full scanning angle. Said signal e3 is integrated, and a signal e4 corresponding to a scanning angle theta is integrated by a signal generator 4. Said signal e4 is converted into a tangent signal by a converter circuit 5, and a position signal e5 is obtained. The signal e4 (or e5) is switched by a switch SW and outputted. An output signal e1 from a detector 1 is inputted to a waveform shaping circuit 6, and the waveform of the signal e1 is shaped and a signal e6 is obtained. The edge part of the signal e6 is detected by an edge part detecting circuit 7. The output of the switch SW is sampled and held in first and second sample and hold circuits 81 and 82 based on a leading and trailing edge signals e7, and a leading edge position signal e8 and a trailing edge position signal e9 are obtained. The difference between both signals e8 and e9 is obtained by a subtractor 9. The result is held by a third sample and hold circuit 83, and a length signal e10 is obtained from an output terminal 12. |
