American Journal of Applied Sciences

On Fractional Hold Devices Versus Positive Realness of Discrete Transfer Functions

M. de la Sen and A. Bilbao- Guillerna

DOI : 10.3844/ajassp.2005.672.675

American Journal of Applied Sciences

Volume 2, Issue 3

Pages 672-675


The appropriate use of fractional order holds (β-FROH) of correcting gains βε[-1,1] as an alternative to the classical zero and first order -holds (ZOH, FOH) is discussed related to the positive realness of the associate discrete transfer functions obtained from a given continuous transfer function. It is proved that the minimum direct input-output gain (i.e. the quotient of the leading coefficients of the numerator and denominator of the transfer function) needed for discrete positive realness may be reduced by the choice of β compared to that required for discretization via ZOH.


© 2005 M. de la Sen and A. Bilbao- Guillerna. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.