高精度超声回波渡越时间算法研究

Algorithm Study of High-precision Ultrasonic Echo Signals

针对时差法超声流量计在测量小管径、低流速时测量精度较低问题,在分析常规测时方法误差机理的基础上,采用互相关算法对回波信号进行处理,通过Hilbert变换提取信号包络,以包络的峰值点作为计时基准点得到超声回波信号精确渡越时间。该算法充分利用信号本身的带通特性,达到滤波和测时的目的,运算简单,具有实时性。实验证明该方法具有较高的测时精度和稳定性。

To solve the low precision problem of the time-difference ultrasonic flow meter for measuring low-flow liquid and the small diameter,based on analyzing the error mechanism of conventional methods of measuring time,the cross-correlation method was proposed to deal with ultrasonic echo signals and the signal envelope was acquired by using Hilbert transform,then the accurate transit time of the ultrasonic echo signals was calculated via the envelope peak point as the timing reference point. The algorithm made full use of the band-pass characteristics of the signal itself and met the purpose of filtering and measurement time. And the algorithm operated simply and had real-time. At last the experiment proves that through the method,the precision and stability of measurement time are improved.