IIR filter design with novel stability condition

A novel stability condition is developed in this paper. It is both necessary and sufficient, which ensures that optimal design cannot be excluded from the admissible solutions. Compared to other necessary and sufficient stability conditions, the proposed one can be expressed as a quadratic constraint in terms of denominator coefficients, which facilitates its combination with other widely used IIR filter design strategies. In this paper, we adopt the Steiglitz-McBride scheme to design IIR filters. In each iteration, an approximation version of the proposed stability condition is further expressed as a set of linear inequality constraints, such that the resulting design problem becomes a quadratic program that can be efficiently and reliably solved. Simulations demonstrate the effectiveness of the proposed stability condition.