自适应FFT功率谱分析在涡街流量计中的应用

The Application of Adaptive FFT Power Spectrum Analysis in the Vortex Flowmeter

针对现有涡街流量计信号处理方式的缺点与不足,提出并实现了一种自适应的FFT功率谱信号分析方法,该法通过硬件电路初判涡街信号频率,与预设分段频率进行比较,由此选取与之匹配的采样频率对涡街信号进行采样,然后通过功率谱分析获得更为准确的涡街信号频率,从而提高流量测量精度。经试验验证:该方法降低了涡街流量计测量下限,拓宽了涡街流量计使用范围。

An adaptive FFT power spectrum analysis method was proposed, to overcome the shortcomings of traditional signal process methods used in vortex flowmeter. In the method, the vibration frequency of vortex signal is roughly measured by an electric circuit to determine a suitable sampling frequency for the FFT process, and the precise value of vibration frequency is determined by the following power spectrum analysis. In the process, the sampling frequency is changing for different bands of vibration frequency. The precision of the vortex flowmeter is improved due to the changing sampling frequency. The result of experiment shows that this method can lower the measuring limit of vortex flowmeter, and expand its use.