Study On Simulation Technology Of Analog Circuit

Circuit simulation is not only applied in circuit design but also in circuit diagnosis. The result of simulation can provide important information to establish diagnosis repository.This thesis is based on the project of"Developing Environment for Fault Diagnosis Software"sponsored by Beijing Aerospace Measurement & Control Corp. It discusses the theory and development of circuit simulation technique. And it studies on new simulation arithmetic.Last the new arithmetic is realized in analog simulation system.First this thesis introduces the development and actuality of system simulation and circuit simulation, as well as the application of system simulation technology to circuit test and fault diagnosis. The project requirement is also described.Then simulation theory is presented and iteration methods used in simulators are also discussed.After that simulation procedure is described.Simulation arithmetic is discussed based on the knowledge of simulation theory.The conventional methods such as Nodal Analysis(NA),Modified Nodal Analysis(MNA) etc,are presented and the drawback of them is also issued. Modified Nodal Analysis based on Transformation(TMNA) is brought forward to solve the sum error problem.And then the TMNA method is improved to solve the loop problem by introducing"virtual node"technology.The new simulation arithmetic TMNA is realized based on the spice simulation engine. Two examples are used to compare the TMNA method and the conventional MNA method. The result indicates that TMNA can solve some convergence problems which MNA cannot handle.Finally the entire work are reviewed and some suggestions are given for the research in future.