Research On Test And Fault Diagnosis Of Mixed-signal Circuits

With the development of Mixed-signal circuits, it brings up new challenge to fault diagnosis of mixed signal circuits. A systematic approach to study testability of mixed signal circuits is urgently needed, because current methods cannot efficiently handle increasingly complex and ever changing circuits. In this paper, we apply a uniform and systematic approach to fault diagnosis problem of mixed signal circuits. The approach is based on a recently developed theory of Discrete Event Systems (DES). It is suitable for the following tasks: (1) checking testability of a circuit; (2) computing minimum test set; (3) finding the degree of testability.The main work and contributions of the dissertation are summarized as follows:We established the fault diagnosis model of the mixed-signal circuits based on DES, analyzed the testability of the mixed-signal circuits and found the ratio of fault coverage. We clarified that it is feasibility for mixed-signal circuits testability analysis and fault diagnosis based on DES theory.In circuits fault diagnosis model based on DES theory, it's greatly difficulty in the testability and the fault diagnosis of the mixed-signal circuits—the computing task minimal testing set. After studying the Rough sets theory in-depth, a reduction algorithm inferred from discernibility matrix and discernibility function which can reduce the dimension of the test vector sets was put forward here on the premise of maintaining the ratio of fault coverage; the experiment result indicated that the algorithm could compress the test vector sets effectively.Automatic Test Equipment (ATE) had become the necessary equipment in testing of electronics. Firstly this dissertation described the development and composition of an Automatic Test System, compared and discussed the bus technology. On the basis of this system, we put forward of design our solution, this system integrated the computer, oscillograph, multimeter and power supply, the computer commanded the other equipments by the GPIB interface.