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Hassouni S.,CED ST | Qjidaa H.,CED ST
International Journal of Wireless Information Networks | Year: 2015

This paper presents a modulator and low power ASK demodulator that uses a new technique. This technique uses the dynamic threshold MOSFET to reduce the threshold voltage of diodes connected MOS transistors as a barrier in the design of the envelope detector. This circuit has been simulated in a 90 nm CMOS technology to satisfy EPC Class 1 Generation 2 standard protocol. The proposed circuit can correctly demodulate the minimum input power −20 dBm for a modulation index of 37–100 % with 40–160 kb/s data rates. The proposed technique has reduced energy consumption at 11.44 nW at 0.4 V, 27 °C. This will increase the operating range of the RFID tags. © 2015, Springer Science+Business Media New York. Source

Sayyouri M.,CED ST | Hmimid A.,CED ST | Qjidaa H.,CED ST
Multimedia Tools and Applications | Year: 2014

In this paper, we present a new set of bivariate discrete orthogonal polynomials defined from the product of Charlier and Hahn discrete orthogonal polynomials with one variable. This bivriate polynomial is used to define other set of separable two-dimensional discrete orthogonal moments called Charlier-Hahn’s moments. We also propose the use of the image slice representation methodology for fast computation of Charlier-Hahn’s moments. In this approach the image is decomposed into series of non-overlapped binary slices and each slice is described by a number of homogenous rectangular blocks. Thus, the moments of Charlier-Hahn can be computed fast and easily from the blocks of each slice. A novel set of Charlier-Hahn invariant moments is also presented. These invariant moments are derived algebraically from the geometric invariant moments and their computation is accelerated using an image representation scheme. The presented approaches are tested in several well known computer vision datasets including computational time, image reconstruction, the moment’s invariability and the classification of objects. The performance of these invariant moments used as pattern features for a pattern classification is compared with Charlier, Hahn, Tchebichef-Krawtchouk, Tchebichef-Hahn and Krawtchouk-Hahn invariant moments. © 2014 Springer Science+Business Media New York Source

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