Study On Analog Circuit Fault Dictionary Based On Semaphore Feature

With the rapid development of electronic technology, analog circuit structure more complex, the complicated system certanly will bring new problem for the maintenance work. Currently the circuit fault diagnosis system faced with the problem of lack of the fault knowledge and fault diagnosis maintenance knowledge. The use of modern circuit simulation technology can achieve fault knowledge acquisition process automation,lower the workload effectively, and can build up the more complete and practical electric circuit test diagnosis knowledge base. This thesis studies analog circuit fault dictionary method based on semaphore feature, and discusses the achievements of crcuit fault diagnosis base on this fault dictionary.First this thesis introduces the development and status of analog circuit fault diagnosis method, as well as the basic principles of fault dictionary method. Three fault dictionary methods are expatiated. They are DC fault dictionary method, AC fault dictionary method and BP network fault dictionary method.To the characteristics of fault dictionary method, the semaphore which is used to enrich data Source of fault dictionary is proposed. Also, the semaphore feature extraction, the semaphore description and the semaphore similarity determination are studied. And the methed of semaphore fuzzy set division is proposed.Then the fault dictionary method combined with semaphore feature, is applied to the actual circuit fault diagnosis. This thesis deals with fault circuit nodes waveform data of transient simulation by feature extraction, and gets the semaphore. Also it uses the fault dictionary method to build fault dictionary.This shows the meaning that the fault dictionary method based on semaphore feature can improve circuit fault diagnosis rate and isolation rate.Finally the entire work are reviewed and some suggestions are given for the research.