Abstract:For the analog filter circuits,a combined fault diagnosis method based on simulation before test and simulation after test is proposed. During the simulation before test,the amplitude frequency response curves of the normal state and fault states are obtained firstly through circuit simulation,the “difference degree” is used to calculate the distinction between the fault status and the normal state,then the detectable fault set of the circuit is determined,furthermore,fault dictionary of the detectable fault set is established through frequency selection. In the simulation after test step,the test data of the fault states is obtained firstly through different frequency excitation,and then calculate the distinction between the test data and the fault features of the fault dictionary according to the “difference degree”,therefore fault detection and fault location are realized by the minimum of the “difference degree". Finally,a simulation example of a filter circuit is given,during the simulation before test,the detectable fault set determination and the establishment of fault dictionary is realized based on the PSpice simulation and the Matlab program,and also the fault detection and fault location based on simulation after test,which verified the practicality of the proposed fault diagnosis method.
