基于DSP的主动型氢钟腔自动调谐系统设计

【作者】 安艳；

【导师】 刘铁新；

【作者基本信息】 中国科学院研究生院（上海天文台） ， 天文技术与方法， 2007， 硕士

【摘要】 氢原子钟具有优良的频率稳定度和准确度，所以它在空间跟踪、导航、射电天文、守时及频率计量等方面均起到重要的作用。由于它使用高有载品质因数微波谐振腔，其振荡频率随腔的谐振频率的变化而变化，即所谓腔的“牵引”效应，这就是产生氢钟长期稳定度变坏的主要原因之一。本论文主要是对主动型氢钟现有的腔自动调谐(CAT，Cavity Auto Tuing)部分进行数字伺服控制以求提高原系统的稳定性和可靠性。主要包括两部分内容：系统的硬件搭建与软件实现。本论文首先给出了系统要实现的目标，第二章介绍了腔自动调谐的工作原理、闭环分析及本设计关键器件的选型。系统硬件设计以16位DSP(数字信号处理器)为核心，本设计选用的16位串行ADC、DAC可与其实现无缝连接，简化了硬件电路结构，增强了系统可靠性。接下来详细论述本系统的硬件各模块电路。第四章介绍了系统软件的设计。根据系统功能强大以及软件升级便利的要求，我们采用Flash在线编程的方法，该方法开发成本低、编程灵活。本论文第五章给出了设计的最终测试结果。本文最后，总结了这个设计的特点，并且提出了对下一步工作的几点思考。更多还原

【Abstract】 Hydrogen atomic clock plays a significant role in navigation, radio astronomy,timekeeping due to its high-stability and precision. Auto-tuning of the maser cavitycompensates for cavity pulling effect, and other sources that contribute to the longterm frequency drift and hence improve the stability of the maser.In this paper, a study of theoretical analysis and design of the H-maserAutotuning systems is presented. Frequency autotuning methods are described. A newscheme is proposed based on DSP(Digital Signal Processor) and CPLD(ComplexProgramming Logic Device). This technique has the desired feature of auto-tuning thecavity with a very high sensitivity and without degrading the maser performance.The thesis is arranged as followed, First of all, the background of the research isbriefly reviewed, and the goal of the autotuning system is presented. Detailedclose-loop analysis and key IC selection is described in chapter 2. Chapter 3 gives thehardware design, we select 16bit DSP TMS320VC5402, which is powerful andhelpful to reduce the complexity of circuit board. In our experiment, we introducedthe connection circuit of 16bit SAR(Successive Aproximation Register)ADC、DACand McBSP in DSP. The software design is presented in chapter 4, we adopted C andassembly programming to realize the signal processing algorithm. The test of thesystem and the results are given in chapter 5.The work is summarized in chapter6, some improvement will be tested in the future.更多还原