ABSTRACT
The methods of design for testability which have been developped for any test sequence can obviously be used for random testing. They are briefly reviewed in Section 13.1. However, if the test sequence is random, it may be possible to take advantage of some specific features.
The random pattern generator may be simplified if a circuit is completely specified; Section 13.2 is concerned by this topic. Section 13.3 shows how some variables may be decorrelated to allow better random testability (an undetectable fault may become detectable and a detectable fault may require a shorter test length). Finally some design methods for combinational circuits, allowing shorter test lengths than circuits obtained by usual methods, are presented in Section 13.4.
