TDR脉冲源和采样关键技术研究
发布时间：2018-10-26 21:10
【摘要】：TDR(Time Domain Reflectometry,也称时域反射仪)是用于检测PCB阻抗、线缆损坏与否的测量仪器。为了更好的在阻抗测量领域中发挥作用,急需提升该测量仪器的性能。TDR的性能体现在测试分辨率和系统带宽,前者由系统上升时间决定,后者则受脉冲源和采样系统共同决定。因此,脉冲源模块和采样系统是提升TDR性能的关键所在。本文研究内容如下:1.分析了匹配传输、反射形成过程以及TDR的工作原理和方案设计,并对TDR的关键技术进行了分析。2.脉冲源的设计。脉冲源的难点在于其输出脉冲既要有较快上升沿,又有要较小的顶部抖动、振铃等特点。本文给出了两种脉冲设计方案。第一种是利用隧道二极管的隧道效应对现有脉冲进行调整,以得到上升沿较快的脉冲。第二种是利用SRD的阻抗变化特性,完成脉冲初步整形,再利用比较器的比较特性对脉冲继续加速,由此得到超快脉冲。通过仿真比较可知,第二种方案得到的脉冲信号的上升沿更快、顶部平坦性更好。3.采样系统中关键技术的研究。在差值采样的基础上,对差值采样系统进行研究并对其中的关键技术进行了分析。本文设计了加减法电路配合功分器的方案对采样过程中的旁通效应进行改善,经过仿真与结果分析可知,旁通效应得到一定的改善。本文给出了基于SRD和微带线组合以及基于雪崩晶体管的两种采样脉冲设计方案。第一种方案的重点在于高幅值超快脉冲信号的产生及脉冲形成网络的设计。第二种方案的重点在于雪崩工作状态的设置及电路中各参数间的协调。经过仿真与结果分析可知,第二种方案得到的采样脉冲的有效底宽更窄、带宽更高、对称性更好。在论文的最后对脉冲源、采样脉冲的设计方案进行了电路设计与测试,并应用在TDR中。经测试可知,脉冲源的上升沿达到57ps,采样脉冲有效底宽230ps左右,系统上升时间约为140ps,系统带宽约为2.5GHz,提高了TDR的测试性能,工程应用价值大。
[Abstract]:TDR (Time Domain Reflectometry, (time domain reflectometer) is used to detect PCB impedance, cable damage or not. In order to play a better role in the field of impedance measurement, it is urgent to improve the performance of the measuring instrument. The performance of the TDR is reflected in the measurement resolution and the system bandwidth, the former being determined by the system rise time. The latter is determined by both the pulse source and the sampling system. Therefore, pulse source module and sampling system are the key to improve TDR performance. The contents of this paper are as follows: 1. The matching transmission, reflection forming process, working principle and scheme design of TDR are analyzed, and the key technology of TDR is analyzed. 2. Pulse source design. The difficulty of pulse source is that the output pulse not only has fast rising edge, but also has the characteristics of small top jitter and ringing. Two pulse design schemes are presented in this paper. The first is to use the tunneling effect of the tunnel diode to adjust the existing pulse to obtain the fast rise edge pulse. The second is to use the impedance variation of SRD to complete the initial shaping of the pulse, and then to accelerate the pulse by using the comparator's comparison characteristics, and then to obtain the ultra-fast pulse. The simulation results show that the rising edge of the second scheme is faster and the flatness of the top is better. Research on key techniques in sampling system. On the basis of difference sampling, the differential sampling system is studied and the key technologies are analyzed. In this paper, the scheme of adding and subtracting circuit with power divider is designed to improve the bypass effect in the sampling process. Through simulation and analysis of the results, it can be seen that the bypass effect has been improved to a certain extent. In this paper, two sampling pulse design schemes based on SRD and microstrip line combination and avalanche transistor are presented. The first scheme focuses on the generation of high amplitude ultra-fast pulse signal and the design of pulse forming network. The second scheme focuses on the setting of avalanche working state and the coordination of the parameters in the circuit. The results of simulation and analysis show that the effective base width of the second scheme is narrower, the bandwidth is higher and the symmetry is better. At the end of the paper, the design scheme of pulse source and sampling pulse is designed and tested, and it is applied in TDR. The test results show that the rising edge of the pulse source is 57 pss, the sampling pulse effective bottom width 230ps is about, the rising time of the system is about 140 psand the system bandwidth is about 2.5 GHz, which improves the testing performance of TDR and has great engineering application value.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM934.7
，
本文编号：2296953
[Abstract]:TDR (Time Domain Reflectometry, (time domain reflectometer) is used to detect PCB impedance, cable damage or not. In order to play a better role in the field of impedance measurement, it is urgent to improve the performance of the measuring instrument. The performance of the TDR is reflected in the measurement resolution and the system bandwidth, the former being determined by the system rise time. The latter is determined by both the pulse source and the sampling system. Therefore, pulse source module and sampling system are the key to improve TDR performance. The contents of this paper are as follows: 1. The matching transmission, reflection forming process, working principle and scheme design of TDR are analyzed, and the key technology of TDR is analyzed. 2. Pulse source design. The difficulty of pulse source is that the output pulse not only has fast rising edge, but also has the characteristics of small top jitter and ringing. Two pulse design schemes are presented in this paper. The first is to use the tunneling effect of the tunnel diode to adjust the existing pulse to obtain the fast rise edge pulse. The second is to use the impedance variation of SRD to complete the initial shaping of the pulse, and then to accelerate the pulse by using the comparator's comparison characteristics, and then to obtain the ultra-fast pulse. The simulation results show that the rising edge of the second scheme is faster and the flatness of the top is better. Research on key techniques in sampling system. On the basis of difference sampling, the differential sampling system is studied and the key technologies are analyzed. In this paper, the scheme of adding and subtracting circuit with power divider is designed to improve the bypass effect in the sampling process. Through simulation and analysis of the results, it can be seen that the bypass effect has been improved to a certain extent. In this paper, two sampling pulse design schemes based on SRD and microstrip line combination and avalanche transistor are presented. The first scheme focuses on the generation of high amplitude ultra-fast pulse signal and the design of pulse forming network. The second scheme focuses on the setting of avalanche working state and the coordination of the parameters in the circuit. The results of simulation and analysis show that the effective base width of the second scheme is narrower, the bandwidth is higher and the symmetry is better. At the end of the paper, the design scheme of pulse source and sampling pulse is designed and tested, and it is applied in TDR. The test results show that the rising edge of the pulse source is 57 pss, the sampling pulse effective bottom width 230ps is about, the rising time of the system is about 140 psand the system bandwidth is about 2.5 GHz, which improves the testing performance of TDR and has great engineering application value.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM934.7
，
本文编号：2296953
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