Testability analysis of analog circuits in the presence of soft, large
-deviation, and hard faults greatly facilitates production of testable
systems. The authors analyze these faults by observing their symptoms
at the circuit's output, an approach that uses the same test methodol
ogy to analyze all three fault types. Their algorithm indicates the se
t of adequate test frequencies and nodes that increase fault observabi
lity They conclude by generating test vectors for observing and coveri
ng these faults.