A simple precision frequency standard comparator

The authors describe a frequency standard comparator based on the characteristics of the greatest common factor frequency and the phase coincidence detection technique. By using a stable and high-frequency common oscillator, the comparator not only can compare frequency standards with a very high accuracy, but can also measure frequency precisely in a wide frequency range. Almost all the circuits in the comparator are digital integrated circuits. This comparator can also be used to compare the frequency standard with other frequencies precisely, if the frequency of the common oscillator is changed