Stability, projection, and convergence of SMM for insufficient order adaptive IIR filters

The stability of the SMM (Steiglitz-McBride method) in the underparameterized case is studied. It is shown that the offline SMM can potentially produce intermediate unstable estimates. A projection technique is introduced and analytically shown to overcome such instability. The existence of multiple stable equilibria for the SMM in the underparametrized case is demonstrated.<
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