Generalized Walsh Transform Sequency-Domain-Based Match Filtering for Electromagnetic Flowmeter Signal Measurement

This article proposes a sequency-domain match filtering method based on the generalized Walsh transform that can accurately measure the slurry electromagnetic flowmeter (EMF) flow. Referring to the construction of binary Walsh functions, we first deduce the mathematical expression of the generalized Walsh functions and provide the proof of function characteristics. Afterward, a method called the generalized Walsh transform sequency-domain-based match filtering method is proposed. This method analyzed the slurry EMF signal (generated by the three-value rectangular wave excitation) sequency spectrum distribution signatures and calculated the signal-to-noise ratio (SNR) to verify the theoretical filtering effect. As for the practical validation, experiments on calibrating the water flow and measuring the slurry flow are conducted to correct the calculation parameters and verify the practical usefulness of the method. Finally, method comparison experiments are implemented to properly evaluate and clearly understand the advantages of the proposed method in processing slurry EMF signals.