Pseudo-random binary sequence interrogation technique for gas sensors

Electrically conducting organic polymers are widely used as a means of gas, odour or aroma analysis using multi-element array techniques coupled with direct current (d.c.) interrogation techniques. Recently, it has been established that the use of alternating current (a.c.) interrogation gives rise to improved performance. In addition, the need to use multi-element arrays is much reduced since a single sensor can be interrogated at a wide range of frequencies. This paper describes the use of pseudo-random binary sequences (PRBS) as interrogation signals for semi-conducting organic polymer gas sensors. Preliminary experiments have been conducted upon volatile vapours and results are presented herein. (C) 1998 Elsevier Science S.A. All rights reserved.