Research Of Phase Noise Measurement Technologies Based On Phase Group Characteristics Between Different Frequency Signals

Time-frequency measurement and control technology is the important foundation of measurement and metrology, instruments and meters, electric power and communication, navigation and positioning, aeronautics and astronautics and other fields, it is directly related to the development of the coresponding science and technology, the progress of the industry and the improvement of measurement accuracy. As an important indicator of frequency source, frequency stability has large influence on the performance of measurement and control system. Allan variance and SSB phase noise are two important representations of short-term stability, SSB phase noise research is hot and receives more and more attention from the researchers because of its more explicit physical meaning. And a large number of phase noise measurement theor ies come up, and related systems are produced.Traditional phase noise measurement methods mainly use phase lock processing at the same frequency in the condition of orthogonal phase. Complex frequency conversion circuits are needed when two compared signals with different frequencies, which increases frequency processing link, improves the cost, introduces the additional error, limits the application of traditional phase processing and the accuracy of measurement. The contradiction between wide frequency measurement range and high measurement resolution in traditional phase processing at the same frequency can not be fundamentally solved by improving circuits and optimizing algorithm. Considering the universality of periodic motion phenomenon and phase problem, phase processing is supposed to have a broader application scope, higher frequency measurement resolution, in-depth study of phase processing theory and method, explore how to expand the traditional phase processing to a wider phase direct comparison and processing between different frequency signals, has the vital significance and research value.In view of the limitation of phase processing at the same frequency in phase noise measurement, based on the in-depth analysis on direct phase comparison phase difference between any two different frequency signals, the dissertation reveals the phase group characteristics theory between different frequency signals, applies the theory to the phase noise measurement, accomplishes the hardware function module and software algorithm design and implementation of the phase noise measurement system based on phase group characteristics, and carries on performance experiments and result analysis. At the same time, this dissertation discusses the applications of phase group characteristics theory in frequency measurement, phase difference measurement and frequency link.The main research contents and research achievements of the dissertation includes the following aspects:1. The dissertation reviews the theory development of frequency stability and phase noise measuremen, introduces the phase noise measurement methods and typical phase noise measurement system, analyzes limitations of the phase noise measurement method based on the same frequency phase processing. Further, Allan variance and SSB phase noise calculation and mutual transformation are also expounded.2. Research of the phase group characteristics theory betwe en different frequency signals. O n the basis of the concept of the least common multiple period, equivalent phase comparison frequency etc., The dissertation analyzes phase difference variation rule between different frequency signals, reveals the phase group characteristics with the the least common multiple period as period, that is, phase group synchronization showing as phase difference consistency between periods and Phase quantization step showing as phase difference q uantization step within periods. The theory has important theory value for simplifying frequency processing link and improving the accuracy of measurement.3. Research of the phase coincidence detection theory between different frequencysignals. On the basis of in-depth study of phase group synchronization, the dissertationanalyzes formation of phase coincidence detection fuzzy area, and discovers its edgeeffect. The research of phase coincidence detection fuzzy area and ite edge effect hasimportant research value and enlightening significance in improving phase coincidencedetection precision, implementing phase noise measurement, and solving thecontradiction between high measurement resolution requirement and limited detectingresolution.4. Research of phase noise measurement principle based on phase group characteristics. The dissertation discusses the application of phase group characteristics in phase noise measurement, using the phase coincidence detection between the reference and measured frequency signals to generate the actual measurement gate. Obtaining the measurement gate time variation by change the count value of the reference and measured frequency signals, the close- in to carrier frequency SSB phase noise measurement achieves; At the same time, obtaining the phase variation by recording the number of phase coincidence detection pulse and the position of the missing pulse, the far carrier frequency SSB phase noise measurement achieves.5. Design and implementation of the hardware and software of phase noise measurement system based on phase group characteristics. The dissertation gives the overall scheme of the phase noise measurement system, completes the design and implementation of the reference frequency source module, DDS and crystal filter module, phase coincidence detection and gate generation module, etc. Also, the author carries out the software algorithm programming, system performance experiment and result analysis.6. Discussion on the other application of phase group characteristics in time- frequency related measurement and control. An approach to raise the speed of phase detection broadband frequency measure ment method at special frequency points is proposed based on precise phase shifting; A phase difference measurement method based on phase group synchronization is proposed. This method compeltes the phase difference measurement by counting the measured and intermediate frequency in the measurement gate which is formed by the phase coincidence detection between the intermediate frequency and the reference frequency, the measured frequency. Also, a frequency link method based on phase group synchronization is proposed. This method uses the stable phase group synchronization phenomenon between complex different frequency signals to realize the high precision transmission of the accuracy and stability without frequency conversation.