For many applications in adaptive signal processing the use of Infinite Impulse Response (IIR) filters could improve the performance of the filter and reduce the number of taps and memory required. This is of special interest in those applications where to implement a Finite impulse Response (FIR) filter implies a very high cost. To solve the drawbacks of the adaptive IIR filter, this paper presents the implementation of a particular polyphase extension of an orthonormal adaptive IIR structure and a related special interpretation of the Steiglitz-McBride method to avoid local minima.