JPS5676015A - Ultrasonic level meter - Google Patents

Abstract

PURPOSE:To obtain a measurement value having a scarce error by a constitution wherein measurement results upto the previous measurement are stored in a holding circuit and by means of the memory voltage, a voltage control type delay pulse generator is controlled and a gate pulse is generated at the estimated position in the next pulse generation time and a gate is switched for a receiving wave to pass through a gate. CONSTITUTION:In response to a pulse signal from a pulse signal source 11, an ultrasonic wave sent through an ultrasonic pulse generator 22 and a wave transmitter 13a is reflected at a plane to be measured 14 and detected in a wave receiver 13b. The output thereof is entered in a receiving signal detection circuit 16 via an amplifier 15 and when an input signal exceeds a setting level, a detection pulse 17 is output. A time difference voltage conversion circuit 22 gives a voltage in compliance with the time difference between a pulse 17 and the delay output of a voltage control type delay circuit 24, to a holding circuit 13. In a holding circuit 23, the hold voltage upto the previous is corrected and the delay of the delay circuit 24 is corrected and the pulse 17 is supplied to a time-voltage conversion circuit 18 by means of the pulse generation circuit 25 through a gate circuit 19. With this, a measurement value having a scarce error can be obtained.