A Self-Equalization Band Pass Filter Having Arbitrary Complex Transmission Zeros

A self-equalization band pass filter having complex transmission zeros is realized in the form of a Foster type network. Complex transmission zeros enable self-equalization to flatten magnitude and group delay times simultaneously in the same bandwidth while maintaining high selectivity by associated attenuation poles. Only a Foster type network has adequate capability to embody such characteristics involving arbitrary transmission zeros. In addition, the Foster type network has another unique capability to allow a new "term by term" frequency transform. This frequency transform enables the suppression of an undesired slope in the group delay times. This slope is inevitably produced when the conventional frequency transform is applied. As a design example, a self-equalization band pass filter applied to a 9 th order Bessel filter is shown.