The Measuring Phase Method of All-phase FFT

To measure sampled sequeces phase values accurately,the phase spectrum of all-phase FFT(apFFT for short)is deeply studied in this paper,and apFFTs property of phase invariant is strictly proved.Thus the apFFT measuring phase method is proposed,which can achieve high-accracy phase measurement without any correcting sepctrum operations that the computation amount is decreased greatly.Simulation experiment proves that the measurement accuracy of the proposed method is 5 amount levels higher than that of the type-1 phase difference method in noiseless circumstances,and the mean square error is only 1/4～1/3 of the one of type-1 phase difference method in high-SNR circumstances.