基于经典谱估计改进方法的涡街流量计

针对涡街流量计高精度、高量程比的要求,在分析涡街信号及其噪声特点的基础上,提出一种采用自适应采样频率和Welch功率谱估计相结合的涡街信号分析处理方法。该方法首先使用经典功率谱估计的FFT算法计算出信号频率的区间范围,然后将信号通过相应截止频率的低通滤波器以防止发生混叠现象,采用信号抽取的方法降低采样频率从而减小频谱的最小频率分辨率,最后采用Welch功率谱估计的方法进行谱分析提高信噪比、减少谱失真。仿真及实验结果表明:所提出的涡街信号处理方法能有效地抑制噪声,实现高精度的功率谱计算,对于提升和改进涡街流量计的性能有良好的效果。

Vortex flowmeter based on improved classical spectral estimation

Based on the analysis of vortex signal and its noise,a kind of digital signal processing method that combines self-adaptive sampling and Welch spectral estimation was proposed to meet the measurement requirements for precision and turndown ratio of vortex flowmeter.First,the frequency range of the signal is calculated using FFT algorithm,and then the signal is filtered with an anti-aliasing low-pass filter.The sample rate is reduced using decimation method to reduce the frequency resolution,and the signal spectrum is estimated using Welch method to improve SNR and reduce spectrum distortion.Simulation and experiment results show that the proposed vortex signal processing method can suppress strong noise and achieve high precision spectral calculation,and has a good effect for promoting and improving the performance of vortex flowmeter.