Fixed-point IIR digital filters with simultaneous hardware usage, group delay and magnitude frequency response specifications

This paper presents a method for the design of stable low-cost fixed-point infinite impulse response (IIR) digital filters with approximately constant group delay in the passband. The design problem is formulated as a discrete constrained optimization problem where the total squared error in the frequency response is minimized subject to constraints on the maximum permitted passband ripple, stopband ripple, group delay ripple, and hardware usage. A new simulated annealing-discrete Lagrangian local search hybrid is used to quickly find near optimal constrained solutions while avoiding constrained local minima with high objective function values