The Design of the Robust Digital IIR Filters

By using the analog cascade elliptic filters desi gn method, and the bilinear method of transforming analog filters to digital filte rs, and the frequency transformation method of digital filters, a simple robust cascading digital IIR filter is designed. The stability of this filter can be as sured by setting rational frequency transformation parameters. The internal magn itude bound of this filter can be minimized by using an empirical optimal method of poles and zeros organization. At the end of this paper, an example of design ing a cascading digital elliptic band stop filter is provided. 