Considerations of the Padé approximant technique in the synthesis of recursive digital filters

The Padé approximant technique provides a quick design of recursive digital filters. An added advantage of the technique lies in that spectrum shaping requirements as well as linear phase constraints can be handled easily, even for higher order filters. This is important in supplying initial guesses of the filter parameters to iterative routines that would then seek a locally optimal design solution. These advantages are among those discussed in a partly tutorial presentation of the technique that relates to filter needs found in data transmission systems. In addition, the question of stability is treated and a new criterion is presented. The criterion provides sufficient conditions in establishing stability for a filter designed by using the Padé approximant technique.