Research On Some Problems About Testability Of The Mixed-signal Circuits

With the development of the microprocessor technology, especially the micro-electronic technology, the complexity of the circuit system and the density of PCB have increased greatly. This made the test of the circuits more difficult. At the same time, the wide application of the mixed-signal circuits gave a great challenge for the present test methods. The testability of the mixed-signal circuits has become an important research task. This dissertation has researched on applying the recently developed Discrete Event System (DES) theory to analyze the testability of the mixed-signal circuits and provided a systemic method for the digital circuits and the analog circuits.The main work and contributions of the dissertation are summarized as follows:Firstly, We researched the mathematics model of mixed-signal circuits based on the DES theory systemically. It was proved that the model was feasible to deal with the fault diagnosis and the testability of the digital and analog parts in the circuits with an uniform frame.Secondly, When we researched the mixed-signal circuits based on the DES theory, one of the important tasks was to find the minimal test set of the circuit in order to reduce the test time and the test cost. In the dissertation we regarded it as an optimization problem and proposed to solve it based on the hybrid strategy of the genetic algorithm and simulated annealing algorithm. We programmed the algorithm and got many solutions at one time.Finally, as for building the DES model of the circuits to be tested, we introduced the EDA tool, Multisim2001, to inject the fault to the circuit, simulate the fault and build the fault information database. The experiment proved the fault simulation method based on Multisim2001 was effective.