Transient response chemical discrimination module

This paper describes a broad-base portable chemical discrimination module capable of using combinations of homogenous or heterogeneous arrays of chemical sensors for evaluating chemical type. Several types of sensors can be added to or removed from the system in plug and play fashion. Using these sensors, the module supplies the user with real-time chemical discrimination information. Included in the module are signal conditioning circuits designed to process chemical sensor signals in such a way that the output of the conditioning circuits ensures similar dynamic and baseline range, regardless of sensor drift, type or fabrication variation. Baseline compensator circuits use a sensor calibration feedback loop to reduce the sensor dynamic range, and so reduce the number of bits required to process a given concentration resolution, thereby reducing power requirements. Additional signal processing is applied to homogenous sensors arrays to reduce the impact of corrupted sensors. Sensor outputs are displayed in principal component space in real-time enabling the user to evaluate the transient path of the sensors to their final position in principal component space for chemical discrimination purposes.