Feature Patterns Extraction-Based Amplitude/Frequency Modulation Model for Vortex Flow Sensor Output Signal

To solve the key problem that vortex flowmeter is susceptible to be disturbed by pipe vibration, the collected data of the vortex flow sensor output signal are filtered, and the amplitudes of the filtered signal are extracted. The fluctuations of both the amplitude and frequency are analyzed and compared so as to study antistrong vibration interference digital signal processing methods for vortex flowmeter. The patterns of fluctuation features are extracted by calculating and analyzing the probability density function and the cycle differenced sequence. Combining with the features of the amplitude modulation and frequency modulation, the mathematical models of the vortex signal, vibration interference, and cofrequency signal are built, and the patterns between the frequency and model parameters are obtained. The effectiveness of the three types of signal models is verified through error analysis, then the reliability of the fluctuation patterns of signal amplitude and frequency is examined, which provides the basis for digital signal processing methods based on fluctuation features.