Design and test of mixed signal circuits: a discrete-event approach

Due to the heavy analog nature of vehicles and the increasing use of microprocessor techniques, most circuits in automobiles nowadays carry mixed (digital and analog) signals. As complexities of these circuits increase, testability of mixed signal circuits has become an important issue that must be dealt with by both design and test engineers. A systematic approach to study testability of mixed signal circuits is urgently needed, because current ad hoc methods cannot efficiently handle increasingly complex and ever changing circuits. In this paper, we develop a uniform and systematic approach to the testability problem. The approach is based on a theory of discrete event systems. It is suitable for the following tasks: (1) checking testability of a circuit; (2) computing minimum test set (i.e., the minimum number of test conditions or test points to verify functionality); (3) assisting with circuit design for testability; (4) finding the degree of testability; (5) dividing a circuit into testable modules