Minimal Realization of Fractional-Order Inverse Filters

Abstract

In this paper, a voltage mode (VM) multifunctional structure of fractional-order inverse filter using a single operational amplifier (op-amp) is proposed. The proposed configuration of inverse filter has been designed using a novel R-C op-amp circuit using minimum number of active and passive components (one op-amp, two resistors and two simulated fractional-order capacitors). The presented structure, by appropriate choice(s) of different passive elements, can realize fractional-order inverse low-pass filter, fractional-order inverse band pass filter and fractional-order inverse high-pass filter. The circuits described are eminently suitable for VM signal processing as they have ideally infinite input impedance. Experimental results using µA741 op-amp, discrete resistors and simulated fractional-order capacitors (α = 0.7) realized using Valsa method, numerical simulations using MATLAB and circuit simulations using PSPICE have been presented to establish the workability of the proposed circuits. The stability and sensitivity analyses have also been presented for the realized fractional-order inverse filters.