| 摘要 |
PURPOSE:To achieve fluid current detection with high accuracy, by using an output, which comes out through a clock pulse delay circuit capable of oscillating ultrasonic wave from a transducer, as a start signal of a time-amplitude converter. CONSTITUTION:An output of a clock pulse oscillator 1, which oscillates 2 ultrasonic wave from transducers 3-a and 3-b through switches 6-a and 6-b, is put into a time- amplitude converter 9 through a delay circuit 13 whose delay time is made a little shorter than propagation time of a ultrasonic wave fluid 5. By doing so, the delay circuit allows a start signal of the converter 9 to be propagated in the fluid and discriminated 7, and the output which had been thus turned into a pulse by a discriminator 8 becomes a stop signal. By setting ultrasonic wave propagation times in forward and backward directions by transducers 3-a and 3-b to T1 and T2, respectively, and by operating values V(T1) and V(T2) holding 10 the output of the converter 9 by an operation circuit 11 into [V(T2)-V(T1)]/[V(T2)X V(T1)], it is possible to detect a time difference between two signals with high accuracy. |
