Realization of BP active filters using UMLF structure with impedance-tapered biquads

Abstract

This paper presents the low-sensitivity realization of band-pass (BP) active resistance-capacitance (RC) filters using "uniform modified leap-frog" (UMLF) structure. Sensitivities with respect to filter passive components are investigated. It is shown how the optimization can be performed in order to achieve minimal sensitivities with relatively small values of Qfactors. Multiple-feedback-structured filters have low sensitivities to passive component tolerances, and additional sensitivity reduction of 2 nd -order building biquads is achieved by the "impedance tapering" design. As an example, the sensitivity analysis, using Shoeffler sensitivity measure, was performed on a Chebyshev 8 th -order BP filter. The filters were realized using UMLF and leap-frog (LF) structures, where sensitivity-optimized single-amplifier (SAB) and Sallen and Key (SAK) biquads realize the 2 nd -order biquads.