Phase Difference Measurement Based on Recursive DFT with Spectrum Leakage Considered

This paper investigates spectrum leakage influence on the performance of discrete Fourier transform (DFT) based phase difference measurement and proposes a novel method with spectrum leakage considered. In the proposed method, spectrum is firstly corrected by interpolation algorithm to remove the influence of short range leakage. To avoid negative frequency interference caused by the long range leakage, real-time phase difference is calculated in succession by a recursive DFT based algorithm with negative frequency contribution. And then, precision of the proposed method is theoretically demonstrated in detail. Furthermore, the method is applied to Coriolis mass flowmeter (CMF). Simulation and experimental results show that the accuracy of phase difference measurement has largely improved, as compared with the existing method based on the sliding Goertzel algorithm.