On Redundancy and Fault Detection in Sequential Circuits
Abramovici, Breuer · IEEE Transactions on Computers · 1979
In this correspondence we show that the well-known concepts of redundancy and undetectability of a stuck-at fault, which are equivalent in combinational circuits, are not equivalent in sequential circuits. We also show that some faults in sequential circuits, which are undetectable (by "conventional" methods of testing), are detectable by transition count testing methods.