A new IIR echo canceller structure

A new recursive adaptive filter structure is proposed, which is composed of a transversal block and a cascade block connected in series. The transversal block implements the zeros of the system function and provides an easy gradient estimation and robust convergence. The cascade block implements the poles of the system function and allows an easy control of the poles positions to ensure stability. The coefficients are updated using either the LMS algorithm, which is robust and simple, or the AFM algorithm, which, in some cases, gives a better performance. Computer simulations indicate that, in some cases, the new echo canceller shows a better performance than conventional realizations.