OSCILLATION MEASURING METHOD BY HOLOGRAPHY

摘要

PURPOSE:To save labor and to achieve automation by shaping the output signal waveform of a vibration detector, provided to a body to be measured, into a rectangular pulse wave, and then emitting a laser at the point of time when a time a half as long as pulse width passes. CONSTITUTION:An vibration signal regarding a body to be measured is shaped by a shaping circuit 200, whose output is shaped by a Schmitt circuit 201 into a rectangular wave, which is sent to a pulse-width measuring circuit 202 and an elapsed-time measuring circuit 203. Information on a pulse width interval Tm measured by the pulse-width measuring circuit 202 is transmitted to a dividing circuit 205 to calculate a value Tm/2, which is held by a holding circuit 206 and transmitted to a collating circuit 207. Information on elapsed time T measured by the elapsed-time measuring circuit 203 is transmitted to the collating circuit 207, which when the value of the information T becomes equal to the value Tm/2 of the holding circuit 206, generates a pulse voltage. When it is applied to a laser chopper device, strobe light conforming in timing with the positive maximum amplitude state of the vibration signal is obtained.