Diagnosis and utilization of faulty universal tree circuits

Abstract

In the last few years the progress of integration techniques of more and more complex digital circuits has led to the development of a new branch of the switching theory known as cellular logic. Nevertheless the integration of cellular circuits of a certain degree of complexity is hampered at present by poor yield, that is by the likelihood that one or more cells of the circuit may turn out to be faulty. It is useful, therefore, to try to use these circuits even when there are some faulty cells. Generally speaking there are two possibilities: (a) to provide a certain degree of redundancy in the circuit, so as to be able to replace the faulty cells with spare cells; (b) to use, if possible, only the part of the circuit functioning correctly.