TDR差分测量方法与多点校准技术研究与软件实现

发布时间：2018-01-08 06:00

本文关键词：TDR差分测量方法与多点校准技术研究与软件实现　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：TDR特性阻抗测试仪是一款利用时域反射法测量阻抗不连续点处特性阻抗的仪器,适用于电路板制造商对PCB迹线进行出厂前质量检验。目前项目组自主研发成功了Asida系列特性阻抗测试仪器,但是在核心的校准与测量技术上面还不够完善,需要进一步的优化,来提高整个系统的测量精度。本论文以提高特性阻抗测试仪的精度为目标,主要工作内容有以下几方面:首先,根据时域反射计(TDR)的基本原理和仪器需要实现的功能,制定TDR特性阻抗测试仪的总体方案,并根据总体方案利用面向对象统一建模语言UML进行软件需求分析建模和软件设计分析建模;第二,分析对比目前业界的差分测量算法,根据自身硬件条件选择了对硬件要求较低,只需单脉冲源和单取样头,但对软件算法要求较高的等效伪差分测试算法,这种差分测试方法不仅降低了开发成本,并且测量结果也在允许的误差范围内;第三,提出了一种改进的校准方法,将传统的两点校准改进为多点校准,测量误差比传统方法降低了2%,传统方法的误差为5%,并将改进的校准方法和等效伪差分测量算法在特性阻抗测试仪中实现;第四,重新设计了特性阻抗测试仪的数据存储模块,采用了数据库管理方案弥补了文档管理方式的缺陷,为项目的进一步发展提供了数据存储空间保证;最后,总结了影响特性阻抗测量精度的几个因素,并给出了解决方案,确保整个系统能够提供更精确的测量服务。本文的校准与测试算法以及数据存储方法均是在VC++平台上实现,并根据项目需要实现的目标,联合硬件平台进行联调测试。经过大量的实际测量实验,将本文结果与泰克、polar等国外仪器的测量结果进行了比较和分析,验证了等效伪差分测量方法和多点校准技术的正确性。数据存储模块,实现了校准测量数据稳定存取、检索和动态扩容,解决了测量数据量大的存储问题。目前该款软件和仪器配合使用的Asida第三代产品能够自动化、批量化、快速、准确地对PCB迹线进行测试,且已经通过系统功能测试和性能测试可以提供给电路板制造商使用,此外系统还有任务管理,波形分析,数据显示,结果分析等功能。
[Abstract]:The TDR characteristic impedance tester is a kind of instrument which uses time domain reflectance method to measure the characteristic impedance at the point of impedance discontinuity. It is suitable for the PCB manufacturer to carry on the pre-factory quality inspection to the PCB trace. At present, the project team has independently developed the Asida series characteristic impedance test instrument. However, the core calibration and measurement technology is not perfect, and further optimization is needed to improve the measurement accuracy of the whole system. This paper aims to improve the accuracy of the characteristic impedance tester. The main work is as follows: firstly, according to the basic principle of time-domain reflectometer (TDR) and the functions that the instrument needs to realize, the overall scheme of TDR characteristic impedance tester is established. According to the overall scheme, software requirement analysis modeling and software design analysis modeling are carried out by using object-oriented unified modeling language (UML). Second, the analysis and comparison of the current industry differential measurement algorithm, according to their own hardware conditions to select the hardware requirements are low, only need a single pulse source and single sampling head. But the equivalent pseudo difference testing algorithm which requires higher software algorithm not only reduces the development cost but also results within the allowable error range. Thirdly, an improved calibration method is proposed. The traditional two-point calibration is improved to multi-point calibration. The measurement error is reduced by 2% compared with the traditional method, and the error of the traditional method is 5%. The improved calibration method and the equivalent pseudo-difference measurement algorithm are implemented in the characteristic impedance tester. In 4th, the data storage module of the characteristic impedance tester was redesigned, and the database management scheme was adopted to make up the defect of the document management mode, which provided the data storage space guarantee for the further development of the project. Finally, several factors affecting the precision of characteristic impedance measurement are summarized, and the solutions are given. To ensure that the whole system can provide more accurate measurement services. The calibration and testing algorithms and data storage methods are implemented on VC platform, and according to the project needs to achieve the goal. Through a large number of practical measurement experiments, the results of this paper are compared and analyzed with the measurement results of foreign instruments such as Tek polar and so on. The validity of the equivalent pseudo-differential measurement method and multi-point calibration technology is verified. The data storage module realizes the stable access, retrieval and dynamic expansion of calibration measurement data. It solves the storage problem of large amount of measurement data. At present, the third generation of Asida products, which are used together with the software and instruments, can automate, batch, quickly and accurately test the PCB trace line. In addition, the system also has functions of task management, waveform analysis, data display, result analysis and so on.
【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

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