【作者】 汪涌；

【导师】 鲁昌华；

【作者基本信息】 合肥工业大学 ， 信号与信息处理， 2008， 硕士

【摘要】 随着电子技术的迅猛发展,电路系统的规模和复杂程度急剧增加,越来越多的电路同时包含了数字和模拟两种信号,使得电路系统的测试难度越来越大。目前的电路故障诊断方法主要是针对数字电路或模拟电路的,而对数模混合电路中数/模两种信号进行统一处理的研究还比较少。因此,开展数模混合电路测试与故障诊断问题的研究,具有重要的理论意义和应用价值。本文运用离散事件系统(Discrete Event System,DES)理论把数模混合电路中的数字信号与模拟信号统一在同一个数学模型下,重点进行了数模混合电路的可测性分析与故障诊断技术的研究。主要工作和成果如下:1.深入研究基于DES理论进行电路可测试性分析的原理,建立基于DES理论的故障诊断的数学模型,并通过各种电路仿真实例阐明了利用DES理论进行电子电路故障诊断的可行性。2.在基于DES理论的数模混合电路测试和故障诊断的研究中,最小测试集的求取是重点和难点。本文结合数模电路故障测试集的具体特点,提出了基于离散粒子群(Discrete Particle Swarm Optimization,DPSO)算法求取电路最小测试集的方法。该方法采用“速度—位置”模型,通过群体中粒子间的竞争与协作在解空间中进行优化搜索。实验结果验证了它的高效性与鲁棒性。3.由于DES理论的运用是建立在故障字典法基础上的,当单独使用这种方法对大规模电路进行故障诊断时会存在很多的冗余测量。针对这一不足,本文使用了一种基于DES和FTA(Fault Tree Analysis,故障树分析)相结合的方法进行数模混合电路的故障诊断。通过实验表明:这种方法能有效的减少测试次数,提高测试效率。4.为使电路的测试具有可操作性,本文提出了数模混合电路虚拟测试系统的设计方案,搭建了基于PCI数据采集卡的测试实验硬件平台,实现了软件系统的部分模块功能。针对具体电路的测试分析和诊断实验验证了使用DES理论进行数模混合电路的测试和故障诊断的有效性。更多还原

【Abstract】 With the fast development of the electronic technology, the complexity of the circuit system increases sharply, more and more electric circuits include digital and analog signal simultaneously, resulting in a greater difficulty in circuit testing. The present methods to test the electric circuits are mainly for digital or analog circuits, and there are few research on the mixed-signal circuits. So it is significant and valuable to study the test of the mixed-signal circuits.In this dissertation, the Discrete Event System(DES) theory is applied to establish a mathematical model applicable for most mixed-signal circuits. The keystone of the dissertation is to analyze the testability of circuit and diagnose the fault of circuit. The main work and contributions are summarized as follows:Firstly, the principle of the testability analysis based on the DES theory is thoroughly studied, the fault diagnosis model of the mixed-signal circuits is established. The simulation result indicates that it is feasible to test the mixed-signal circuits based on the DES theory.Secondly, in the research of the fault diagnosis of mixed-signal circuits based on the DES theory, how to find out the minimal test set of circuits is important and difficult. Considering the characteristic of the minimization of the test set of the mixed-signal circuits, a minimization approach for circuit test set based on discrete particle swarm optimization algorithm is put forward. With the "velocity-position" model, an optimum solution is searched in the result space by means of competition and cooperation among the particles of swarm. The experiment result testifies that the approach is efficient and robust.Thirdly, an approach to the fault diagnosis of mixed-signal circuits which combines the FTA (Fault Tree Analysis) method with the DES theory is used to reduce the redundant test vectors. The experiment analysis indicates that the approach is effective in improving the speed of testing.Finally, a virtual test system with a PCI DAQ device is proposed and designed so as to make the test of circuits operable. An experiment to test a factual mixed-signal circuit is done with the test system. The result validates that the DES theory is effective in testing and diagnosing the mixed-signal circuits.更多还原