RC-Amplifier Resonators for Active Filters

Author

Geffe, Philip R.

Volume

15

Issue

4

fYear

1968

fDate

12/1/1968 12:00:00 AM

Firstpage

415

Lastpage

419

Abstract

Active filters may consist of a cascade of isolated resonators, with each resonator supplying a single pair of complexconjugate poles. This paper supplies a detailed analysis of some $RC$ -amplifier resonators whose characteristics are well suited for practical filters. The calculations are facilitated by a set of sensitivity identities. One resonator, taken from the Sallen and Key catalog, is shown to have extremely low passive sensitivities: $S_{Z}^{Q} = \\pm frac{1}{6}$ for all passive elements. Active $Q$ multiplication is used to extend the usefulness of the circuit. Analysis of the dualintegrator feedback resonator shows that it is notably insensitive to amplifier parasitics. Finally, the dual-integrator concept is realized in a resonator that uses only two amplifiers. The several resonators supply a range of useful pole- $Q$ \´s from low values to several hundred.

Keywords

Active filters; Active filters, etc.; Integrators; Operational amplifiers; Q-multiplication; Resonator circuits; Sensitivity analysis; Active filters; Circuit analysis; Costs; Feedback loop; Impedance; Output feedback; RLC circuits; Resonator filters; Senior members;

fLanguage

English

Journal_Title

Circuit Theory, IEEE Transactions on

Publisher

ieee

ISSN

0018-9324

Type

jour

DOI

10.1109/TCT.1968.1082846

Filename

1082846