Multiple-parameter tunable digital filters using submultiple sampling techniques

A multiple-parameter variable digital filter is proposed which is derived from periodically switched analogue networks. A bilinear expansion of the system matrix with pairwise commutative matrices leads to a structure in which the significant parameters can be tuned independently. This method is demonstrated by a 2nd-order digital filter section. As an example, the results of a 2-parameter tunable 3rd-order lowpass filter are presented.