Abstract: A new method for phase difference measurement based on time comb technology is introduced in this paper. The math model of time comb is given, and its characteristic is analyzed. The principle is used in data acquisition of high frequency. Equivalent sampling technology is abstained from low frequency and measured signal， avoiding high sampling frequency and combined with multilayer correlation technology. Then phase difference is detected when the Nyquist sampling theorem is not satisfied. Simulation results show that the high resolution for high frequency signals especially in low signal-noise ratio condition. It can be widely used in engineering.

Key words: Time comb, High frequency signal, Phase difference, Multilayer correlation