| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an accurate flow measurement which is superior in responsiveness. Ž<P>SOLUTION: In this flowmeter, the number of clock pulses counted in the period from the transmitting point A of an ultrasonic wave to the arrival point B of received wave is stored in the forward direction and backward direction during preliminary measurement of previously measuring the propagation time of the ultrasonic wave; the number of clock pulses is started to be counted from the transmitting point A of the ultrasonic wave during the measurement after the preliminary measurement; integration is started at an output point C of the clock pulse by two pieces before the number of clock pulses stored in the forward direction and the backward direction; integral voltages V1 and V2 are measured at the arrival point B of the received wave; and the minute period T2 is calculated. Thus, propagation time is measured, based on the clock pulse time T1 and minute time T2. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
