ULTRASONIC FLOW VELOCITY MEASURING DEVICE AND ULTRASONIC FLOW VELOCITY MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To avoid an aliashing in an ultrasonic flow velocity measuring device for measuring the flow velocity in a pipeline. ;SOLUTION: An ultrasonic pulse is transmitted from an ultrasonic sensor 18 provided in the vicinity of the wall of a pipeline into the pipeline at a prescribed transmitting frequency ft and a transmitting repeated period T, and the ultrasonic wave after transmission is received to output a received signal, and the sampling of the received signal is preformed at a sampling period T, and a Fourier transformation is performed in an FFT 24. When the frequency determined in the FFT 24 circulates when the transmitting repeated period T is successively changed from small one to large one, an aliashing is judged. The frequency determined in the FFT 24 is subjected to the processing of adding or subtracting the portion of the frequency corresponding to the circulating frequency width.;COPYRIGHT: (C)2001,JPO