Electronically tunable analog active filters

1 May 1972

journal article
Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Circuit Theory

Vol. 19 (3) , 299-301
https://doi.org/10.1109/tct.1972.1083446

Abstract

Electronically tunableRC-active ladder filter transfer functions are realized by employing the four quadrant analogue multiplier as the basic nonlinear network element. All the frequency dependent branches of a conventionalRC-active ladder structure realizations are simulated by means of impedance scaling networks. The scaling of these impedances allows the cutoff frequency of an elliptic low-pass or high-pass transfer function, of arbitrary order, to be varied by means of a tuning voltage. The method is strictly analogue and leads to practical filters that employ presently available integrated circuits; external timing signals or reference oscillators are not required in order to accomplish tuning.

Keywords

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Electronically tunable analog active filters
IEEE Transactions on Circuit Theory, 1972
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