基于回波峰值拟合的气体超声流量计信号处理

Signal processing for ultrasonic gas flowmeter based on peak fitting of echo

针对从气体超声波流量计回波信号中难以确定到达时刻,而仪表又要求具有较高实时性的问题,提出一种基于回波上升段峰值拟合的气体超声流量计信号处理方法,以及拟合峰值范围的确定方法。首先根据拟合峰值范围,在回波信号的上升阶段,选取若干个峰值点,对各峰值点进行最小二乘拟合,得到特征直线,将该直线与X轴的交点作为特征点,确定回波信号的到达时刻,进而计算出超声波传播时间,得到气体流量。研制实现基于回波上升段峰值拟合的气体超声流量计,进行标定实验,以验证方法和仪表的有效性。

Aiming at the problem that it is difficult to determine the arrival time from the echo signal of the ultrasonic gas flowmeter and the instrument is required to have high real-time, a new signal processing method for ultrasonic gas flowmeter based on peak fitting of rising echo and a method to determine the fitting peak range are proposed.Firstly, according to the fitting peak range, several peak points are selected in the rising section of the echo signal, and they are fitted by the least squares to achieve the feature straight line.The intersection of this line and the X-axis is regarded as a feature point to determine the arrival time of the echo signal, and then the ultrasonic propagation times are calculated to obtain the gas flow rate.The ultrasonic gas flowmeter is developed to implement the signal processing method based on peak fitting of rising echo.The calibration experiments are preformed to validate the effectiveness of the methods and the meter.