Author: Desmond Francis Sheahan

Publisher:

Published: 1967

Total Pages: 260

ISBN-13:

The report discusses integrated circuits which simulate, in an inductorless fashion, the detailed behavior of the LC filter structure. Two distinct methods are described. The first of these uses exactly the conventional LC filter structure and merely replaces each inductor by an integrable circuit that behaves like an inductor. The circuit takes the form of a frequency-independent, two-port network which, when terminated at one port by a capacitor, presents an inductive behavior at the other port. This impedance inverting network, or gyrator, can be constructed from a pair of controlled sources. The dissertation analyzes this type of gyrator, derives a set of requirements for high-quality performance and describes a specific circuit which meets them. Experiments on a complex band-pass filter confirm that it is possible to obtain low sensitivity filters by this means. The second method simulates the LC filter structure by making a complete model in the manner of an analog computer. Two special circuits were devised to perform, very precisely, the operations of subtraction and integration. These were designated the Difference Amplifier and the Difference Integrator. In an attempt to produce a universal circuit arrangement that would be applicable to all classes of filter, these basic units were used to build the principal canonical tandem section due to Darlington and Brune. These simulated Brune sections were used to construct a low-pass, a high-pass, and a band-pass filter.