| 摘要 |
PURPOSE:To reduce the time of measurement by converting the propagation time of ultrasonic wave pulses to voltage level value by making use of the charging phenomenon of a capacitor. CONSTITUTION:The pulse signal output from a clock pulse transmitter 21 is transmitted from a transmitter 2-a into fluid and is received in a receiver 3-a. This signal is then converted to the pulse signal D by a discriminator 10-a. On the other hand, in a time/amplitude circuit 11-a, the pulse signal from a clock pulse transmitter 21 and the time difference of the output pulses D of a discriminator 10-a are converted to voltage signals by using the integration action of a capacitor or doing others and the signal corresponding to the propagation time per time of the ultrasonic burst wave passing the transmitter and receiver is obtained by way of a counter 13-a or the like. The signal corresponding to the propagation time of the ultrasonic burst wave from the transmitter 2-b up to the receiver 3-b is also obtainable in a similar manner. Since in this way no repetitive frequency measurements of the propagation time are done, the time of measurement may be shortened. |
