Low-pass digital filter with amplitude 1/f2 attenuation based empirical mode decomposition of vortex signal processing method.

Abstract

To improve the measurement performance of the vortex flowmeter, a low-pass digital filter with amplitude 1/f2 attenuation based empirical mode decomposition (EMD) of the vortex signal processing method is proposed. According to the amplitude-frequency characteristic of the vortex signal, a second-order low-pass digital filter is used for vortex signal preprocessing. Due to the amplitude 1/f2 attenuation characteristic of the second-order low-pass digital filter, the high frequency noise can be filtered out and the amplitude of the vortex signal can be normalized. Referring to the result of normalization, an amplitude threshold is set, which will be used as the criterion for selecting the effective vortex signal component after EMD. The simulation experiment and real flow anti-interference experiment are conducted. The experimental results show that the proposed method can adaptively select the vortex signal component and has advantages over the traditional methods based on EMD in terms of frequency measurement accuracy, operational efficiency, and anti-interference performance.