Vectorial Impedance Meter for Gas Chemical Analysis

In this paper two digital correction techniques are presented aiming at enhancing the measurement accuracy of an electronic nose. The equipment operates as a vectorial impedance meter in the frequency range 0-15 MHz. The digital correction techniques allows to compensate for the conditioning electronic response. Linear behaviour is assumed, cross-talk, amplitude and phase distortions are accounted for by a black box two-ports model. The model parameter are evaluated either with a set of measurements, (input sine bursts) spanning the whole frequency range and by a single measurement (two uncorrelated noise inputs) exploiting autoregressive (ARX) modelling.