Signal Phase Difference Estimation Based On Coherent Wavelet Transform

With the rapid development of electronic science and computer technology,the estimation and measurement techniques of phase difference have been deeply penetrated into many fields and have a wide range of applications.Obtaining the phase difference and precisely estimating the phase difference between two signals is very important for the applications of the real signals. When the traditional methods are used, which are based on analog circuits or digital chip,such as zero-crossing hardware detection method,the high estimmating precision can not be obtained. Therefore,the software based methods have received wide attentions from many scholars.In this paper,the coherency wavelet transform method is used to estimate the phase difference between two signals.The performance of the algorithim is analyzed and demonstrated in detail.The main content of this paper are as follows:(1) Based on wavelet transform,the coherency wavelet transform method is used to estimate the signals’phase difference.The performance of the proposed method is valided by numerical simulation.It is also respectively compared with the cross-correlation and discrete time Fourier transform (DTFT) method.The simulation results show that the coherency wavelet method has good estimation performance and high estimation precision.As the changes of SNRs,the mean square phase delay errors of the algorithm don’t vary very much with the SNRs.(2)The method based on coherency wavelet transform is used to estimate the phase difference between non-stationary signals.The simulation results show that the phase difference of non-stationary signas can be estimated.The method can be used for non-stationary signals,and have good estimation performance.(3)The parameters setting have influences on the estimation performance of the coherency wavelet based method.The parameters studied in this paper include the time domain sampling rate,the frequency resolution and the center frequency of the mother wavelet function.The parameters’ influence to the performance of the whole algorithm is studied.(4) The coherency wavelet transform method is used to estimate the phase difference between the two signals collected by magnetic detection.The results prove that the algorithm proposed in this paper can be applicable for the practically collected signals.The coherency wavelet transform method is proposed to estimate the phase difference between two signals.The study results will provide a basis in the applications of signals’phase difference measurement.