Designs of FIR filters with optimized group delay

In this paper, a novel method is proposed to design FIR filters. In our designs, the objective is to reduce the minimax approximation error of an FIR filter subject to peak error constraints imposed on group delays in passbands. Starting from an initial design, the proposed method employs an iterative procedure. In each iterative step, a nonlinear equation is solved to make group delay constraints satisfied. Simulation results demonstrate that the proposed method can achieve FIR filters which satisfy group delay constraints arbitrarily specified in passbands.