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A refined classification of single amplifier filters
Author(s) -
Sedra Adel S.,
Brown Les
Publication year - 1979
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.4490070114
Subject(s) - negative feedback , control theory (sociology) , positive feedback , sensitivity (control systems) , complement (music) , operational amplifier , class (philosophy) , amplifier , negative feedback amplifier , mathematics , transformation (genetics) , filter (signal processing) , computer science , topology (electrical circuits) , electronic engineering , engineering , bandwidth (computing) , artificial intelligence , electrical engineering , telecommunications , combinatorics , voltage , chemistry , biochemistry , control (management) , complementation , gene , phenotype , computer vision
It is shown that Single Amplifier Biquads (SAB's) may be grouped into two major categories, the Enhanced Negative Feedback (ENF) and the Enhanced Positive Feedback (EPF). These two major classes of circuit are related by the complementary transformation and hence exhibit identical sensitivity performance. In the extreme, the ENF class degenerates to the familiar Negative Feedback (NF) class while the EPF class reduces to the Positive Feedback (PF) case where the op amp is connected in a unity‐gain configuration. Depending on the order of the RC feedback network, each class includes two subclasses with different sensitivity performance. The paper examines in detail the ‘enhanced feedback’ mechanism, and investigates the optimum design of the Deliyannis—Friend circuit and its complement the Sallen and Key positive feedback configuration.