关键词: 超声波, 传输时间, 回波信号, 流量测量

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Abstract:

In accordance to the characteristics that ultrasonic wave echo signal is a periodic signal with variational amplitude of each wave,a precision measurement of ultrasonic wave transmission time through digital subdivision method was proposed.The principles of ultrasonic transducer drive circuit as well as how to
realize this method by using high-resolution A/D and high-speed FPGA circuit to actualize high frequency data sampling from ultrasonic wave echo signal were illustrated.A ultrasonic flowmeter was designed based on these methods and circuits.It is pointed out that the measurement resolution of ultrasonic wave
transmission time depends on the frequency of ultrasonic signals and the revolution of A/D circuit.In order to improve measurement accuracy,the sampling frequency should be as high as possible. Because the measurement of ultrasonic wave transmission time is based on all ultrasonic wave echo signal sampling data, it has good reliability and strong anti-interference ability.

Key words: ultrasonic wave, transmission time, echo signal, flow measurement