Picosecond Level Research on Phase Difference Measurement between Signals of Multiple Frequencies

To meet the demand for high-precision timing signals in modern science, this paper proposes using the phase information of sine waves as a fine marker for timing signal measurement, which is expected to accurately synchronize timing signal errors to the picosecond level. The non-drifting multiplication signal of sine wave phase can be used to characterize the fine phase information within one cycle of a sine wave signal. The prerequisite for measuring the picosecond-level phase drift between different frequency signals is the calibration of the phase drift between the multiplication signal and the sine wave signal. Currently, there is no instrument that can measure the phase difference between different frequency signals with picosecond-level accuracy. This paper innovatively designs a picosecond-level accuracy measurement circuit for the phase difference of different frequency signals. It analyzes the influence of power dividers, amplifiers, mixers, filters, and attenuators used in the circuit on the signal phase. The circuit itself causes a time difference of no more than 3 ps for the measured phase difference, and the stability of the measurement results is in the range of E-13, proving that the accuracy and stability of the measurement circuit meet the requirements of picosecond-level high-precision measurement. This creates conditions for further calibrating the phase drift between signals and accurately characterizing the phase information of sine waves to achieve high-precision timing signal synchronization.