On the design of nearest optimal recursive linear shift-variant digital filters

A technique of designing recursive linear shift-variant digital filters is described for which the filter coefficients are simple functions of the cutoff frequency of the filter. It is shown that the filters designed by this method are optimal for the criterion of least square errors at the cutoff frequency of the prototype filter, and nearest or approximated optimal at other cutoff frequencies. Details of the design technique are discussed. An example is included to illustrate that the method proposed is computationally efficient