The Research Of Technology Of High Precision Frequency Link Based On Phase Group Synchronization

This article reveals the regularity of phase variation in periodic phenomena, presents new concept as phase group synchronization and phase quantum, and deepens some concept theory as greatest common factor frequency and equivalent phase comparison frequency. Compared with the traditional processing approach, the application of new concept theory into the atomic clock can simplify the circuits and improve the performance of atomic clock, produced the technology of high-precise frequency link based on phase group synchronization and phase group process between periodic signals.According to the variation characteristics of the phase relationship between the periodic signals, the theoretical knowledge of phase group synchronization and the method of phase group processing, and the comparison of phase difference of the two voltage-controlled crystal oscillator output signal, via feedback and the processing of data results, the voltage-controlled crystal oscillator which output frequency standard is phase-locked controlled to achieve high-precision frequency link.This technology of frequency Links has simplified and improved the wiring section in the traditional structure of the atomic frequency standard, so that the frequency multiplication and synthesis circuit, feedback and control circuit achieve simple and integrated. The technology not only reduces phase noise in the conventional frequency conversion circuit, but also significantly improves the performance of the output signal of the atomic clock, which performs a high degree of accuracy and long-term stability index, while maintaining good short-term stability and phase noise indicators produced by the voltage-controlled oscillator itself, achieving high precision frequency link at last.Cesium atomic clock has the highest degree of accuracy and good stability, mainly working for satellite navigation. Hydrogen atomic clock has the highest degree of stability, currently at the stage of research and extension applications. The advantage of rubidium atomic clock is small in size, mainly used in commercial.By comparison, the paper select cesium atom as the atomic physics, and output 10MHz frequency standard signal with frequency link technology.In this paper, the cesium atomic clock hardware circuit is divided into four parts:signal shaping module is that two controlled oscillators in this circuit output pulse signals after amplification, filter, Schmitt trigger; CPLD frequency division module is that 10MHz controlled oscillator after 10 million divided output signal of 1Hz; time difference measurement module is that 1Hz and 14.591479MHz frequency signals through phase comparison read out their time difference in the least common multiple period; MCU module control the time difference measuring chip and the 10MHz VCO. The controlled oscillator outputs divided frequency signal which is using CPLD with Quartus Ⅱ software and Verilog language throgh online program and test, to achieve the function of counter which can divid frequency. MSP430F169 microcontroller debugging is using IAR to realize the time difference measurement unit and the controlled oscillator control and achieve frequency link circuit function which can voltage control the VCO. Through a combination of software and hardware, the cesium atomic clock circuit after transformation outputs frequency standard signal with long-term stability of 10E-13/ day, short-term stability of 5E-12/s, and the distal end of the phase noise of-162dBc/ Hz@1MHz.Atomic frequency standard is widely applied to the field of metrology as a frequency measurement and punctuality, time synchronization and time measurement, the field of engineering technology as navigation and positioning, digital communications.