Abstract: A new method for phase difference measurement is introduced in this paper. Because the sinusoidal signal has a particular trait, do cross correlation to the two signals to get cross correlation function and keep the phase difference information. Multi-layer cross-correlation function is obtained by multi-layer cross correlation calculation to the cross-correlation function, and phase difference is obtained by using correlation theory. Length of sampled data, signal-noise ratio，number of ADC quantization bits and harmonic content which influence precision of phase difference measurement are particularly discussed and analyzed. Simulation results and conclusion are given. The simulations proves its feasibility and effectiveness to detect the phase difference.This method has many virtues such as simple theoretic deduction and explicit physical signification.It is especially fit for low signal-noise ratio condition or negative signal-noise ratio condition and it can get high resolution.

Key words: Phase difference, Multilayer cross-correlation, White noise