Network transformations for incorporating nonideal simulated immittances in the design of active filters and oscillators

Although the usual methods of designing active filters through the inductance simulation and frequency dependent negative resistor (FDNR) approaches necessarily require active networks capable of simulating ideal inductors and ideal FDNRs, this paper describes network transformations which make it possible to incorporate even nonideal (lossy) simulated inductance and FDNR elements directly into the filter design. It is shown that the use of these transformations leads to novel filter configurations having many advantageous features. The proposed transformations also prove to be important tools for deriving new sinusoidal oscillator configurations which have properties which are not possible with known oscillator circuits and for providing new interpretations and insights into known oscillator circuits. Experimental results are given which confirm the validity of the theory.