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

摘要：

根据超声波回波信号是一个变幅周期性信号这一特点,提出一种用数字细分来精密测量超声波传输时间的方法,阐明了超声波换能器驱动电路原理及利用FPGA电路和高分辨率A/D电路通过高频采样来实现这一方法的原理,并采用该方法和电路设计了超声波流量计。指出超声波传输时间测量的分辨率取决于超声波信号的频率和A/D电路的分辨率,为保证测量精度,应尽可能采用较高的采样频率。超声波传输时间的测量综合了全部回波信号采样数据,有很好的可靠性和很强的抗干扰能力。

关键词: 超声波, 传输时间, 回波信号, 流量测量

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