Ultra-resolution phase comparison method combining phase synchronous detection and common frequency source

With the improvement of frequency standard comparison and precise frequency and phase processing technique, the high-precision frequency measurement, phase comparison, phase locked loop and signal processing are necessary. Combining phase synchronous detection principle and common frequency source, an ultra-high resolution phase comparison method is presented in this paper. Using the concepts of the equivalent phase comparison frequency, group period phase processing, phase group synchronization and phase quantization step and so on, and the high stability of common frequency source, the resolution with picosecond or subpicosecond can be easily obtained and ±1 count error in traditional phase comparison approach can be eliminated. Experimental results show that the measuring precision better than femtosecond in one hour can be achieved in the long-term frequency standard comparison.

► We achieve the measuring resolution with higher than 10−15/h.
► We realize the phase comparison, measurement and control with different frequency.
► We discover that the variation of group phase difference has a linear law.
► We find phase group synchronization and quantization step law between any signals.