Phase difference measuring method based on data extension and Hilbert transform

The invention relates to the field of signal processing and particularly relates to a phase difference measuring method. The phase difference measuring method with an applicable object of a same frequency sine signal comprises the following steps: firstly, performing data extension on two same frequency sine signals and enabling the signals (data extension signals) subjected to the date tension to become integer-period sampling signals; secondly, performing Hilbert transform on the data extension signals to obtain analytic signals; thirdly, calculating cross-correlation and self-correlation of the analytic signals to respectively obtain cross-correlation signals and self-correlation signals; finally, performing cross-correlation calculation on the cross-correlation signals and the self-correlation signals to obtain a cross-correlation function, and obtaining a phase difference estimated value by utilizing weighted average of the phases of the cross-correlation function. The phase difference measuring method based on data extension and Hilbert transform related in the invention can be used for improving the phase difference measuring precision and improving the noise resistance of the phase difference measurement by sufficiently utilizing the same-frequency sine signal information.