A high-resolution frequency standard comparator based on a special phase comparison approach

Along with the accuracy enhancement of atomic frequency standards (FS), a higher FS comparison resolution is necessary. Based on the concept of the greatest common factor frequency and a common frequency source, utilizing a phase coincidence detection approach, the high-resolution phase comparison between FS can be completed. The resolution of the simple instrument is better than 10 ps, and the resolution of theoretical analysis is much higher. In the long-term FS comparison, higher than 1×10^-14/hour accuracy can be obtained and for one day comparison the measuring precision can be 10^-16. This method can also be used in the measurement of short-term frequency stability or as a terminal display device of an FS comparator, and 10^-13/τ stability resolution can be obtained.