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基于FPGA的精密时间—数字转换电路研究
【作者】 宋健；
【导师】 安琪；
【作者基本信息】 中国科学技术大学 ， 物理电子学， 2006， 博士
【摘要】 时间是物质存在和运动的基本属性之一。精密的时间作为科学研究、科学实验和工程技术诸方面的基本物理参量，为一切动力学系统和时序过程的测量和定量研究提供了必不可少的时基坐标。精密的时间不仅在原子核物理研究、粒子物理研究、地球动力学研究、相对论研究、脉冲星周期研究和人造卫星动力学测地等基础研究领域有重要的作用，而且在诸如航空航天、深空通讯、卫星发射及监控、地质测绘、导航通信、电力传输和科学计量等应用研究、国防和国民经济建设中也有普遍的应用，甚至已经深入到人们社会生活的方方面面，几乎无所不及。精密时间测量的基本手段是精密的时间数字转换电路。 精密时间数字转换电路有多种实现方法，本论文主要研究的是利用现场可编程逻辑器件(FPGA)中的专用进位连线来实现精密的时间数字转换电路。FPGA中有着丰富的资源，目前已经有很多基于FPGA实现时间数字转换电路的研究工作。本论文在调研了以前时间数字转换电路工作的基础上，对用FPGA中的专用进位连线来实现时间数字转换电路的研究进行了全面详细的介绍。另外，还详细介绍了对实现的时间数字转换电路进行测试的测试系统设计，最后给出了实现的时间数字转换电路的测试结果和分析。 论文的第一章从物理实验、国防应用、工业应用及仪器三大方面介绍了时间数字转换电路的需求，并分别以物理实验中的第三代北京谱仪、国防应用中的激光测距和工业仪器中的PET等为例介绍了时间数字转换电路的具体应用情况。 第二章介绍了实现时间数字转换电路的主要方法和手段，尤其重点介绍了当前主流的时间数字转换电路实现方法——“粗”时间测量加“细”时间测量，并对其中“细”时间测量的技术方法做了进一步的介绍。 第三章描述了时间数字转换电路中常用的几个技术指标，这些技术指标刻画了时间数字转换电路的性能。另外，本章还简要分析了时间数字转换电路中误差的一些来源，并对转换器校准进行了简单介绍。 第四章首先介绍了FPGA的发展、结构和原理，并对目前几大FPGA供应商的产品进行了总体介绍。在本章的最后介绍了到目前为止用FPGA来实现时间数字转换电路的各种技术和方法。 第五章是本论文的关键，在这一章中介绍了利用FPGA中的专用进位连线实现时间内插的设计思路，各种FPGA器件中进位连线资源，以及实现时间内插方法的尝试研究。最后分别在Altera和Xitinx公司的FPGA器件中实现了时间内插电路，并对实现的时间内插电路进行了时序仿真。 第六章首先调研了物理实验对时间数字转换电路的需求，然后介绍了当前物理实验中典型的时间数字转换器件——HPTDC，并介绍了我们设计的利用FPGA中专用进位连线实现的时间数字转换电路，最后对设计的时间数字转换电路进行了时序仿真。
【Abstract】 Time is one of the basic physical attributes of the world we live in. The accurate time not only gives an essential parameter to science research, experiments and engineering technologies, but also works as an indispensably ruler for all dynamics systems and sequential procedure. The accurate time is not only important in basic research such as atom physics research, particle physics research, earth dynamics research, relativity theory research, pulsar period research, and artificial satellite dynamics research etc., but also very important in applied research, defense and economy such as navigation and spaceflight, deep space communication, satellite emission and monitor and control, geological mapping, navigation communication, power transmission, and scientific measurement etc. The accurate time has almost been used in all aspect of the life. The accurate time is measured by using precise time-to-digital converter circuits.There are many methods to realize precise time-to-digital converter circuits. In this paper, we introduce our research work on realizing precise time-to-digital converter circuits by using the dedicated carry chain of FPGA. There are many resources in FPGA. There are many works about using the resources of FPGA to realize time-to-digital converter circuits. Based on the survey of previous works, we put forward and introduce our method of realizing precise time-to-digital converter circuits by using the dedicated carry chain of FPGA. Then we introduce the design of the test system which is designed for testing our time-to-digital converter circuits. At last, we show the test results and analyze the results.In first chapter of the paper, the requirement of time-to-digital converter circuits is introduced from the aspects of physical experiments, defense applications, and industrial applications and instruments. Especially, we introduce the applications of time-to-digital converter circuits in the BESIII of physical experiments, laser range finder of defense applications, and PET of industrial instruments.Chapter two introduces the main techniques and methods to realize time-to-digital converter circuits, especially introduces the popular structure of time-to-digital converter circuits—coarse time measurement + fine time measurement. At last, the methods of fine time measurement are introduced detailedly.Chapter three clarifies the metrics adapted to the specific application of time-to-digital converter circuits, including Differential Non-Linearity (DNL) and Integral Non-Linearity (INL). These metrics describe the performance of time-to-digital converter circuits. Dynamic error sources such as noise and crosstalk are also discussed. The calibration of time-to-digital converter circuits is also introduced.In fourth chapter, the development, structure and principle of FPGA are introduced. This chapter also introduces the products of several FPGA providers. We survey all time-to-digital converter circuits based on FPGAs. In the end of the chapter, we introduce all of the techniques which are used to implement time-to-digital converter circuits in FPGAs.