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Proceedings Paper

Temperature-modulated gas sensors: selection of modulating frequencies through noise methods
Author(s): Eduard Llobet; Alexander Vergara; Jesus Brezmes; Radu Ionescu
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Paper Abstract

Metal oxide gas sensors suffer from lack of selectivity and response drift. The use of sensor dynamics has been introduced to ameliorate sensor performance. The usual approach consists of modulating the operating temperature of gas sensors. Temperature modulation alters the kinetics of the adsorption and reaction processes taking place at sensors' surface. This results in response patterns that are characteristic of gas/sensor pairs. Despite the fact that a great deal of work has been done, the selection of the modulating frequencies remains an obscure and non-systematic method. A new approach to systematically select frequencies is discussed. The method is based on the use of pseudo-random binary sequences (MLS) to modulate the working temperature of gas sensors in a wide frequency range. The impulse response of a pair sensor-gas can be estimated from the circular cross-correlation of the MLS and the sensor response sequences. From the study of the impulse response in the frequency domain, an identification of the modulating frequencies that convey important information to both identify and quantify gases is obtained.

Paper Details

Date Published: 25 May 2004
PDF: 11 pages
Proc. SPIE 5472, Noise and Information in Nanoelectronics, Sensors, and Standards II, (25 May 2004); doi: 10.1117/12.547626
Show Author Affiliations
Eduard Llobet, Univ. Rovira i Virgili (Spain)
Alexander Vergara, Univ. Rovira i Virgili (Spain)
Jesus Brezmes, Univ. Rovira i Virgili (Spain)
Radu Ionescu, Univ. Rovira i Virgili (Spain)

Published in SPIE Proceedings Vol. 5472:
Noise and Information in Nanoelectronics, Sensors, and Standards II
Janusz M. Smulko; Yaroslav Blanter; Mark I. Dykman; Laszlo B. Kish, Editor(s)

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