| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem in finding propagation time of an ultrasonic wave in which a time lag arises between measurements, such as measurement - switching - measurement, since an operation takes place for switching between a transmission-side oscillator and a reception-side oscillator. SOLUTION: A flow rate operation means 38 is capable of calculating a flow velocity by separating time periods of opposite propagation from each other based on timing values obtained by a first clocking means 36 for measuring a time period taken by an ultrasonic signal directly propagating between vibrators 32 and 33, and by a second clocking means 37 for measuring a propagation time period taken by an ultrasonic signal reflecting at least twice between the vibrators so as not to cause a substantial time lag. Further, transmission/reception directions are switched through switching operation for accuracy enhancement. COPYRIGHT: (C)2008,JPO&INPIT |
