Fault Isolation of Electronic Circuits Using Transfer Function Methods

摘要

Dynamic testing techniques based on operational calculus or transformation methods are potentially capable of extracting deterministic information about the status of a system from its input and output. Methods have been studied which by means of linear transformations of input and output generate numerical information about the polynomial coefficients in numerator and denominator of the system's transfer function. A unifying theory covering all methods based on linear transformations has been developed. Of specific interest are methods where the transformations are mechanized by means of physical networks (transformation filters), because of their possible simplicity and their real time properties. The simplest transformation filter is a low-pass RC network which basically performs a Leftsided Laplace Transformation. Methods extracting a large amount of information from just input and output are hampered by the propagation of observational errors into the solution of a pertinent set of equations. This propagation is in general amplificatory and if uncontrolled it easily becomes explosive. Methods have been worked out to minimize this error amplification. Minimum error amplification, however, increases with the number of polynomial coefficients and other factors determined by the physical structure of the system to be tested. (Author)