基于群相位量子化处理的相位噪声测量方法研究

Phase noise measurement plays an important role in precise frequency source characteristics and frequency-standard research, application and test.Aiming at the very complex frequency transformation processes and the contradiction among wide frequency range, quick response time and high resolution and so on in the traditional phase noise measurement.Based on different phase processing,the following study will be developed in this project. First,combined with the principle of different frequency phase detection,the measured frequency is densely sampled at zero-crossing point by using high frequency reference pulse as the clock of AD converter.Then the information of phase coincidence and phase coincidence deviation is recovered.The faster response time and higher gate opening velocity are reached by the control and processing of phase coincidence information.Second, the uninterrupted gate time with high resolution is measured,whose variation of width reflects the size of phase noise,by combining the law that phase noise varies with group phase difference and using the method of group period phase processing.Third,a transformation algorithm of gate variation and phase noise with small amount of calculation and high reliability is designed , which can truly reflect the single side band(SSB) phase noise of the measured signal through the data abtained by transformation. According to the research above, a phase noise measurement method with quick response time in wide frequency range is proposed based on group period phase processing. This method will provide the theoretical guidance and the key technical support of phase noise measurement for the high-tech areas which use various oscillator and atomic frequency standard, such as aeronautics and astronautics, navigation and positioning and so on.

相位噪声测量在精密频率源的特性、频率基、标准的研究、应用及性能测试中具有重要作用。针对传统相位噪声测量方法需要复杂的频率变换过程且难以兼顾宽频率范围、快响应时间及高分辨率的问题，本项目以异频相位处理为基础拟开展如下研究：用高频参考脉冲作为AD转换器的时钟，结合异频相位检测原理，对被测信号在过零处密集采集，恢复出相位重合及重合有偏差的信息，通过对重合信息的控制和处理，加快闸门响应时间；结合相位噪声随群相位差变化的规律，采用群周期相位处理方法，在宽频范围内实现高分辨率的无间隙门时测量，用门时长短的变化反映相位噪声的大小；设计一种计算量小、可靠性高的门时变化与相位噪声转换算法，所得数据能真实反映被测信号的单边带相位噪声。通过上述研究，提出一种基于群相位量子化处理的相位噪声测量方法，该方法将为使用各种振荡器和原子频标的航空航天、导航定位等高科技领域提供对其关键的相噪测量方面的理论指导和技术支持。

传统的相位噪声测量常采用锁相处理的方法，多建立在同频鉴相基础之上，而针对不同频率信号之间的相位比对，需借助混频、倍频、频率合成等系列变换过程，使其频率归一化。频率的归一化处理一方面使电路结构变得复杂、影响仪器小型化，另一方面也极易引入附加线路的噪声、加大了测量精度的不确定性。为此，本项目以发现群相位量子化处理的规律、阐明其重要特征、完善其理论体系并解决其实际工程问题为目标，提出了基于群相位量子化处理的相位噪声测量方法研究，历时3年，在国家自然科学基金的资助下，取得了系列研究成果，形成了多项技术创新，主要包括： .1、得到了基于时频多参数测量的群相位量子化处理方法，降低了相位噪声对测量精度的影响；通过频标信号对被测信号的相位同步和跟踪，提高了测量分辨率及其稳定性；提出了最大公因子周期、群量子化相位等概念，发现了群量子化相位变化的科学规律，实现了频率准确度和稳定度的精密测量和传递，从相位群的视角解决了传统相位处理方法存在的瓶颈问题。. 2、提出了高分辨率异频群量子化相位处理方法，实现了时间、频率、相位噪声等时频多参数测量；提出了模糊区特征脉冲信号检测方法，解决了由硬件不一致性和不匹配性所带来的系统误差，提高了测量精度。. 3、提出了同步时钟技术中的多层次时间测量和控制方法，解决了宽测量范围和高分辨率之间的矛盾问题；提出了基于群周期相位处理的宽频快速频率测量方法，解决了频率测量的宽测量范围、快响应时间和高分辨率的统一性问题；提出了宽频率测量范围、快响应时间及高分辨率的相位噪声测量方法，为弱信号检测及其稳定度的测量提供了科学依据。.相位噪声测量是高精度时间频率传输与比对要解决的关键问题之一，这个问题的解决有助于提高精密频率源尤其是原子频标的频率稳定度和准确度，并对整个精密测量物理领域的发展及其在商业、民用、国防、军工等领域的广泛应用起到强有力的推动作用，具有重要的理论和现实意义。