Nonlinear phase FIR filter design with minimum LS error and additional constraints

The problem of approximating a complex frequency response by a real-valued FIR (finite impulse response) filter according to the L/sub 2/ norm subject to additional inequality constraints for the complex error function is examined. Starting with the Kuhn-Tucker optimality conditions which specialize to a system of nonlinear equations, an iterative algorithm is derived. These equations are solved by Newton's method in every iteration step. The algorithm allows arbitrary compromises between an L/sub 2/ and an L/sub infinity / design. The L/sub 2/ and the L/sub infinity / solutions result as special cases.<>