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Journal of Applied Mathematics
Volume 2013, Article ID 157292, 7 pages
http://dx.doi.org/10.1155/2013/157292
Research Article

A New Fractional Order Hold and Its Capability in Frequency Response and Zero Placement

1Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
2Faculty of Electrical and Computer Engineering, Bonab University, Bonab, Iran
3School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran

Received 17 March 2013; Revised 12 June 2013; Accepted 2 July 2013

Academic Editor: Hak-Keung Lam

Copyright © 2013 Farzad Hashemzadeh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper introduces a new holder with application on digital control systems. This holder is a combination of fractional order hold (FROH) and zero-order hold (ZOH) that has the capability of both holders and a frequency response better than both of ZOH and FROH. For the stability of zeros of the sampled system two theorems are stated and proved with the assumption that the sampling period is very small. Also simulation results are studied to show the effectiveness of the proposed holder and better performance results in comparison with ZOH and FROH.