Fractional-step Tow-Thomas biquad filters

Todd J. Freeborn, Brent Maundy, Ahmed Elwakil
2012 Nonlinear Theory and Its Applications IEICE  
In this paper we propose the use of fractional capacitors in the Tow-Thomas biquad to realize both fractional lowpass and asymmetric bandpass filters of order 0 < α 1 + α 2 ≤ 2, where α 1 and α 2 are the orders of the fractional capacitors and 0 < α 1,2 ≤ 1. We show how these filters can be designed using an integer-order transfer function approximation of the fractional capacitors. MATLAB and PSPICE simulations of first order fractional-step low and bandpass filters of order 1.1, 1.5, and 1.9
more » ... 1.1, 1.5, and 1.9 are given as examples. Experimental results of fractional low pass filters of order 1.5 implemented with silicon-fabricated fractional capacitors verify the operation of the fractional Tow-Thomas biquad.
doi:10.1587/nolta.3.357 fatcat:nhjjidkjznbvxoyyzaa25z4r4e