A new approach for the selection of test points for fault diagnosis

A new criterion and an efficient algorithm for the selection of test points in multifrequency fault diagnosis of linear circuits are presented. The proposed criterion exploits the biquadratic nature of the response in terms of circuit parameters instead of the common use of first order sensitivities. Accordingly it is capable of handling catastrophic faults. Employing the proposed criterion, an efficient two-phase fault diagnosis algorithm is introduced. The first phase selects a set of test points and characterizes the response for possible faults. This is done without the simulation of a preselected set of faults. The second phase efficiently isolates on-line actual faults using test points without any computation. A test example is presented to demonstrate the effectiveness of the proposed criterion and algorithm.