Design of a mean filter algorithm for phase difference measurement based on Fourier transform

Because of non-coherent sampling, Fourier transform when used for the measurement of phase difference is insufficient in terms of the accuracy and real-time. This paper starts with the analysis of the relationship among the phase difference error, the frequency skew and the true phase difference. Then a mean filter algorithm, which can eliminate the phase difference error as far as possible by taking advantage of the symmetry of the function, is proposed. Comparing with traditional Fourier transform based phase difference measurement algorithm, the proposed algorithm can filter out the error well, improving the accuracy of phase difference measurement.