Computational algorithm for the design of elliptic filters

A simple and fast algorithm, based on the simultaneous cheby¿shev character of the passband and stopband characteristic, is presented for the computation of the transfer function of elliptic filters. The algorithm does not use elliptic functions; rather, a set of nonlinear equations is established and solved using Newton´s method. Since useful initial approximations are easy to find, the solution requires only 2¿4 iterations. The results are obtained directly in the transformed variable z and hence are immediately usable for computer-aided design.