A high-precision frequency measurement method combining π-type delay chain and different frequency phase coincidence detection

A high-precision frequency measurement method combining π-type delay chain and different frequency phase coincidence detection is proposed based on different frequency phase comparison. A delay chain is used to delay the frequency standard signal. The coarse delay can generate more phase coincidence points at the key position of the reference gate, which can easily form a high-precision actual gate and realize a fast response time of the frequency measurement. The fine delay can achieve an ultra-high measurement resolution better than picoseconds without changing the frequency relationship between the frequency standard signal and the measured signal. The experimental results show that the proposed method has a high frequency accuracy and stability. Compared with the traditional frequency detection method, it has the advantages of simple circuit, fast measurement speed, and high measurement accuracy. Therefore, it can be widely used in satellite navigation, space positioning, metrology, communication, precision time–frequency measurement, and other fields.