A singular-value decomposition approach for ambiguity group determination in analog circuits

An efficient approach for ambiguity group determination in low-testability analog linear circuits is presented. It is based on the use of the singular-value decomposition of the testability matrix of the circuit under test, and permits us to determine canonical ambiguity groups also in the case of circuits of relatively large dimensions. The new approach is characterized by a numerical robustness not present in previous approaches, which give only an estimate of both testability and ambiguity groups. A program implementing the proposed method has been developed by exploiting symbolic analysis techniques. Examples of application of the new approach are considered through the use of this program.