| 摘要 |
PURPOSE:To prevent the degradation in response speed by measuring the velocity or rate of flow of fluid to be measured without causing malfunctions and defective indication even when he fluctuations in the amplitude of the received ultrasonic wave pulses are intense. CONSTITUTION:At every outputting of an ultrasonic wave pulse from an ultrasonic wave receiver 3a, a measuring circuit 4 for propagation time detects the specific pulses of the received signal and the clock data obtained by said detection is supplied to a statistical pocessing circuit 5. The circuit 5 determines the weight function W(t) which is a ''0'' when t<(Tp1-DELTAT), (Tp1+DELTAT)<t and is a ''1'' when (Tp1-DELTAT)<=t<=(Tp1+DELTAT) in accordance with the data (value Tp1) on the propagation time corresponding to the max. peak from the distributions of m pieces of the clock data when said data is supplied from the circuit 4, determines one average propagation time Tmean 1 by multiplying said weight function W(t) and the distributions of m pieces of the clock data and stores said time Tmean 1. The circuit 5 determines an other average propagation time Tmean 2 similarly when an ultrasonic wave transmitter-receiver 3b starts the transmission of the ultrasonic wave pulses, and operates and determines the flow rate of fluid 2 to be measured in accordance with the times Tmean 1 and Tmean 2. |
