A SPICE method for designing digital filters from analog filters

Usually IIR digital filters are designed by using analog filters described in time or transform domain, then by converting the analog filters to digital filters using appropriate transformation from s-domain to z-domain. For many engineers analog filters mean certain circuits or a netlist of components, and digital filters are a set of statements in certain software. In this work, we show how to obtain a digital filter from a given netlist of an analog filter by skipping the transfer function description.