| Abstract: | This paper theoretically establishes that estimations of G‐parameters, given in a classical reference, are biased rather than unbiased as stated in that reference and that the diagnostic criterion, proposed in that reference, is unfounded. The paper further presents a set of inequalities that are the necessary and sufficient conditions for ensuring the validity of the G‐criterion against biased estimations. The incorrect diagnosis, performed by the G‐criterion, is inevitable regardless of the degree of the faults if the set of harsh inequalities is not satisfied. As these inequalities can be easily checked quantitatively with nominal data of the circuit to be diagnosed, they can be used to forecast which of the nodes faults cannot be correctly located with the G‐criterion. In the last section, the simulation provides a solid support for the theoretical analysis in this paper. Copyright © 1999 John Wiley & Sons, Ltd. |
