NEW DIRECT DISCRETIZATION OF THE FRACTIONAL-ORDER DIFFERENTIATOR/INTEGRATOR BY THE CHEBYSHEV-PADÉ APPROXIMATION

This paper deals with the use of the Chebyshev-Padé approximation (CP) in order to achieve accurate direct discrete-time approximations to the fractional-order differentiator/integrator. It is shown how, for a given order of the transfer functions, CP is much more accurate at low frequencies than the continued fraction expansion (CFE). Furthermore, CP can be more accurate than a CFE approximation of a higher order.