Active filters with zero amplifier sensitivity

A general characterization of second-order active-RC filters employing one, two, and three operational amplifiers is given. When certain conditions are met, it is shown that the desired poles can be rendered insensitive to first- and second-order changes in the time constants of the operational amplifiers. Several novel circuits possessing this zero pole-sensitivity property, as well as zero and sensitivity properties, are presented and discussed. Experimental verification of the results and comparisons to other popular second-order active-RC realizations bear out the significantly superior performance of these filters.