High-precise frequency measurement and link based on phase group synchronization

Frequency and phase measurement resolution close to Femtosecond level has great significance for the progress of frequency standard technology and the precise time and phase synchronization processing. The precise link between frequency signals is mainly used for quantum frequency standard and complex, precise frequency control situations. It makes signals which have great frequency difference establish strict correlation between frequency and phase, and achieves the transmission between frequency accuracy and stability. Traditional widely used frequency measurement and link technology which is based on frequency processing have disadvantages of complex equipment and limited resolution. Phase processing has the highest resolution in all time-frequency processing but it has been ignored in processing between complex signals, because the limit that only the same frequency signals can be phase processed. The characteristics of greatest common factor frequency, least common multiple period, phase quantization step phenomenon, equivalent phase comparison frequency make us achieve the phase group processing method based on phase group synchronization phenomenon. The phase quantization step value between different frequency signals which are often encountered in radio frequency will be small to picosecond, Femtosecond, and even sub-femtosecond, and that is to say the equivalent phase comparison frequency between the corresponding two radio frequency signals can enter into microwave band and light band. And it also provides basis for the precise frequency measurement and link which are based on phase group processing between frequency signals in different frequency bands. Based on phase group synchronization, this paper obtains a super high measurement resolution up to magnitude of fs. By the control of phase group synchronization the accuracy and stability in signals of different nominal frequencies can be transferred. It will be with significant application value in freq- ency measurement, quantum frequency standard and phase-locked loop field.