Operational frequency bandwidth rescalable implementations of constant phase devices

Abstract

This paper presents and verifies a method for rescalability of operational bandwidth in constant phase devices (two-port elements, two-port transfer blocks). Most importantly, in comparison with a standard approach, it allows to utilize suitable values of capacitance in the case of operation at low-frequency bands. The capacitance multipliers based on a controllable variable gain amplifier are implemented in examples of simple fractional-order systems (two-port integrators). These examples consist of novel bilinear immittances with independently settable zero and pole frequency coordinates, based on widespread commercially available current conveyors of second generation. The capacitance multiplier extends features of the bilinear immittance and full implementation of the system. PSpice simulations, using off-the-shelf elements, confirm operability of the proposed concept.