Fault Identification in Electronic Circuits with the Aid of Bilinear Transformations

A method has been developed for applying bilinear transformations to the identification of faulty components in linear electronic circuits. Simple magnitude and phase measurements, at a number of test frequencies, are made and plotted on a set of predetermined loci in the complex transfer-function plane. The data for plotting the loci are determined either experimentally or by circuit analysis with a digital computer. The faulty component and the parameter value are then determined from the loci. The method has the advantage that it provides a graphical representation of the circuit behavior with a faulty component and also readily allows experimental error to be taken into account when plotting the measured data. The method is demonstrated with a practical transistor amplifier circuit.