The Measurement And Control Of Frequency Sources Based On Phase Process

Time-frequency measurement and control technology is closely related to various fields,including aerospace,military,exploration,astronomy,power communication and so on.With the rapid replacement of time-frequency system,the requirement of frequency source measurement and control technology is getting higher and higher.Phase is one of the important parameters of periodic phenomena.The measurement method based on phase processing has high measurement accuracy and resolution.Traditional frequency measurement methods mainly have the shortcomings of positive and negative one word counting error,long response time,complex circuit and so on.With the development of modern science,the requirement of time-frequency measurement and control technology is getting higher and higher,so it is significant to integrate phase processing into measurement and control.Based on the in-depth analysis of phase processing theory,this paper designs a frequency measurement and control system based on phase processing.In the measurement system,first the reference signal and the measured signal are converted to digital signal,and then the two signals are detected by phase coincidence detection,then the measurement results are obtained.In the control system,the voltage controlled crystal oscillator is connected with the measured end.The phase difference between the voltage controlled crystal oscillator and the reference signal is converted to the voltage controlled voltage.The output frequency of the voltage controlled crystal oscillator is adjusted by the voltage controlled voltage.Phase stepping and phase group synchronization in phase processing theory are applied in frequency measurement and control system based on phase processing.Phase stepping phenomenon is reflected in the analog-to-digital conversion process based on clock cursor effect.When the special frequency relationship between the sampled clock signal and the sampled signal meets the requirement of clock cursor effect,the original information of the sampled signal can be recovered well.The measurement accuracy of the whole system is determined by the conversion accuracy of the measured signal and the reference signal.In order to reduce the quantization error in the signal sampling process,the edge effect of the quantized ambiguity region formed by analog-to-digital conversion can be used.Compared with other locations,the resolution stability of the edge of the quantized ambiguity region is better,and it is more sensitive to the change of the measured signal.By quantifying the edge of the ambiguity region to obtain the stable value,the low-bit analog-to-digital converter with high conversion rate can achieve the best performance.The phase group synchronization phenomenon is applied to the comparison between the measured signal and the reference signal.The measurement gate is set with the phase coincidence point of the two signals as the sign to ensure the synchronization of the measurement gate and the two signals,which can reduce the counting error of one word.Based on the analysis of the principle of the experimental scheme,the feasibility of the scheme is verified by the self-calibration and cross-ratio measurement experiments and the voltage controlled crystal oscillation control experiments.The short-term frequency stability of 10^-12/s can be obtained in the measurement,and the short-term stability of Voltage controlled crystal oscillator can also be improved.Compared with the existing frequency measurement and control system,the measurement and control system designed in this paper does not need to introduce mixers,frequency multipliers and other devices for frequency conversion,and combines phase processing and digitization,which provides a new idea for time-frequency measurement and control technology.