Research And System Implementation Of Aging Compensation Based On Equivalent Parameters Of Crystal Resonators

With the advent of the 5G era,there is a higher requirement on the stability of the clock and it's frequency source and only high-accuracy and high-stability frequency sources can guarantee time synchronization and stability of signal transmission.High-stability crystal oscillators are favored by the majority of companies for their relatively inexpensive price and mass production,but their long-term stability is slightly different from the requirements of the times.The atomic clock with good stability index is expensive,The development of an ultra-high stability crystal oscillator that meets the standards of the 5G era is of historic importance.Based on the research of high-stability crystal oscillators,seeking an effective means to suppress the aging of crystal devices or compensate for the frequency offset caused by aging factors can greatly enhance the long-term stability of crystal oscillators.This article builds on previous experience with aging compensation,based on the study on equivalent resonant parameters of crystal devices.The change of resonance frequency of resonance circuit must be accompanied by the change of component parameters in the circuit.The change of component parameters is the aging of the crystal device.Due to the fact that it is difficult to accurately measure the resonant parameters of the crystal device by current technical means,the phase shift effect of the crystal is studied.It is a feasible method to judge the aging condition by the crystal device's change of the phase shift amount of the high-frequency signal.By analyzing the signals at both ends of the internal resonator of the crystal oscillator,digital devices are used to measure the amount of phase shift at both ends of the crystal resonator in the resonant circuit.The same-frequency signals at both ends make the sampling values of the ADC correlate.The ADC is originally used.Based on the reference of the clock signal,the correlation between the two sampling values at the two ends of the resonator is analyzed and the sampling of the ADC is optimized.One of the two signals is used as a clock signal,and the other is used as a sampled signal.For a stable single sample value,the frequency jitter is also in a relatively stable range.The change of the phase shift will inevitably cause the change of the sample value,thus calculating the phase shift amount,that is,the variation of the sample value and the related law of the frequency offset.In addition,frequency compensation is performed to suppress the effect of aging drift.In this paper,the relevant laws of the two are calculated through specific measurement data,and a system is designed.The MCU control module actively adjusts the voltage control voltage of the crystal oscillator according to the change of the sampling value.The experimental results show that the system effectively compensates the crystal's aging drift frequency,and the frequency drift within 5 days is reduced by 10 times,and the frequency drift within 45 days is reduced by 3 times.The key to the compensation effect of the system is to establish the corresponding relationship between the phase shift variation and the resonant frequency variation.The most important significance of this study is to find a new method to effectively compensate the aging of the crystal device,and verify the feasibility of the solution through system design.Sex.It has provided new ideas for self-developed crystal oscillators with higher stability and lower aging rate,and has a high research value.