An efficient design of fractional lead filter via fractional order system

In this paper the design method of the digital fractional lead operator zα for 0 < α < 0.5, in a given frequency band of interest, using digital Infinite Impulse Response (IIR) filters is presented. In this technique, the coefficients of the closed form digital IIR filter derived for the approximation of the fractional lead operator, in a given frequency band, are based on the approximation of fractional order systems. First, analog rational function approximation, for a given frequency band, of the fractional power zero (FPZ) is given. Then the Tustin (bilinear) generating function is used to digitize the FPZ to obtain a closed form IIR digital filter which approximates the digital fractional lead operator zα for (0 < α < 0.5). Finally, an example has been presented to illustrate the effectiveness of the proposed design technique.