A novel approach to stable IIR digital filter design

In this paper, the problem of designing stable infinite impulse response (IIR) digital filters is discussed. Based on a continuous-time state-space structure and the generalized bilinear transformation, a new parametrization for stable IIR digital filter design is proposed. One of the advantages of this parametrization is that the corresponding stability region is the entire parameter space and hence the design can be carried out using well-established unconstrained optimization methods. Two design examples are presented to demonstrate the performance of the proposed approach and to compare it with an existing one, which show the superior behavior of the filters obtained with the proposed approach to those achieved with the existing one.