Circuit design of an integrable simulated inductor and its applications

Gyrator principles are used to design an integrable voltage-controlled simulated inductor with inductance variable from 0.1 to 250000 H or even higher. One of the features of this simulated inductor is that it contains two voltage-controlled current amplifiers with controlling terminals connected in parallel. For a resonant circuit consisting of such a simulated inductor and an external capacitor, the resonant frequency will be linear with the controlling voltage. It can be employed to realize a sine-wave oscillator or filter whose operation frequency is changed linearly with the controlling voltage. In this work a linear voltage-controlled sinusoidal oscillator, which was designed to have an oscillation frequency from several kHz down to 0.01 Hz, is taken as an example to illustrate an application of the simulated inductor. In this case the simulated inductor was made up of discrete components and the oscillator has been employed to provide standard signals for research on differential transformation of physiological spikes in medical science