| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic velocity meter that prevents malfunctions and wrong measurements of an apparatus, with respect to occurrence of abnormalities by air bubbles and the like. SOLUTION: Two kinds of burst signals with phase difference are generated by a burst signal generator 110 to transmit to a pair of ultrasonic probes 6, 7 for transmission and reception arranged on the upstream side and on the downstream side of a fluid 9 to be measured. The ultrasonic probes 6, 7 convert the burst signals and transmit the ultrasonic waves, and also receive the ultrasonic waves propagated in the fluid to be measured to convert to received signals. The received signals are binarized by binarized circuit 16, 17 and are formed into phase difference signals expressing the phase difference by an exclusive OR circuit 30, and the speed of the fluid 9 to be measured is measured with a calculation circuit 36, based on the phase difference signals. A decision part 114 decides whether the peak level of the received signals are larger than a threshold level; and when the peak level is not larger, it will decide them as being abnormal signals and will exclude the abnormal signals so as not to calculate the speed by using the phase difference. COPYRIGHT: (C)2005,JPO&NCIPI
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