Research Of The Testability And The Fault Diagnosis Of The Mixed-signal Circuits Based On The DES Theory

With the increase of the complexity of the circuits, the circuits testing fields have to be confronted with a strange challenge. Nowadays more and more chips contain both digital and analog signal simultaneously. However, the Discrete Event System (DES) theory proposes a mathematical model applicable for most mixed-signal circuits testing and fault diagnosis, gives out a solution to the main difficulties concerned to a certain extent. This thesis using this theory analyses and studies the mapping relation between the state and the event of the mixed-signal circuits, and finds the minimal test set and the fault dictionary of the circuits.The main works are summarized as follows:Researched the mathematics model of the testability and the fault diagnosis of the mixed-signal circuits in the DES frame.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 circuits in order to reduce the test time and test cost. In the dissertation we proposed to solve it based on chaos search and chaos genetic algorithm. And this paper studied and analyzed some algorithms of computing the minimal test set of circuits.A complete practice on a circuit fault diagnosis under the instruction of the DES theory was applied. In the diagnosis and analysis process, EDA tool - Multisim2001 was used to build the DES model for circuits testing.