A new approach to the Fourier analysis of periodic signals for the minimization of the phase errors

The methods used to reduce the errors in the determination of the harmonic phase of periodic signals by means of digital techniques are considered. The authors first briefly review the theory of the discrete Fourier transform (DFT) in order to discuss the genesis of the phase errors. They then give evidence that this approach has no general validity. An original method to minimize these phase errors while keeping the computation burden comparable with the of the classic FFT algorithm is proposed. The results of some experimental work done to verify the proposed method are reported, showing that the phase errors can be reduced by up to two decades with respect to those of the usual methods