超声波硫酸分析回波波至点确定方法研究

Study on the Determination Method for Arriving Point of Echo in Ultrasonic Sulfur-acid Analysis

在超声硫酸浓度分析过程中,系统内部和外界环境存在很多干扰噪声,因此无法准确确定超声波回波波至点的位置,故采用小波分解方法加以解决。针对超声波信号的非奇异性,首先对信号进行Hilbert变换;然后再进行拟小波分解和阈值滤波;最后,利用FPGA构建小波变换模型并找到波至点。研究结果证明,该方法可以准确确定波至点,大大提高了硫酸浓度测量的精确度。

In the process of ultrasonic sulfuric acid concentration analysis, a lot of interference noise exists in both internal and external environment of the system ; thus the position of the ultrasonic echo arriving point cannot be determined exactly, so the wavelet decomposition method is adopted to solve this problem. Considering the non-singularity of ultrasonic signal, the signal is firstly processed by Hilbert transformation, then it is decomposed by quasi wavelet and filtered in accordance with the threshold, finally FPGA is used to build the wavelet transformation model to find out the arriving point. The result of research shows that the arriving point can be accurately determined by this method and the measurement accuracy of sulfuric acid concentration is greatly increased.