Design of IIR digital filters in the complex domain by transforming the desired response

In this paper, we present a new design method of IIR digital filters with an equiripple magnitude response in the complex domain. This method is based on solving a least square solution iteratively. At each iteration, the desired response is transformed so as to have equiripple error. Hence the algorithm is very simple and does not need a special software. By this method, an equiripple solution is obtained very quickly with less computational complexity. Finally, we show some examples to validate the proposed method.