Study on DFT Algorithm Detecting Coriolis Phase Difference

An improved algorithm of using DFT (Digital Fourier Transform) to detect phase difference in CMF (Coriolis Mass Flow meter) is described. In the algorithm, firstly an estimated frequency is used to calculate phase difference several times; from the phase difference change, a more precise estimation of the current period can be got. By adjusting the length of the DFT calculation, a more precise phase difference is achieved. This method can also overcome the spectral leakage in the phase difference calculation, which is mainly induced by the change of the CMF natural frequency. Our CMF experiment has demonstrated that the accuracy of CMF is improved by adopting the improved algorithm.