Fast Transient Classification With a ParallelizedTemperature Modulated E-Nose

In this thesis work, a novel operating principle for a temperature modulatedelectronic nose is introduced. The main goal is to perform gas discrimination with metal oxide gas sensors in natural, uncontrolled environments where thesensors are exposed to patches of gas only for short periods of time. The proposed Parallelized Temperature Modulated electronic nose (PTM e-nose) allows to speed-up discrimination of gases by measuring in parallel theresponse of n gas sensors of the same type but with a phase-shifted temperaturemodulation cycle. The basic idea is to replicate the base sensor n times with each sensor instance measuring one different nth of the modulation cycle. In this waythe response to the full modulation cycle for one sensor can be recovered from n different sensors in one nth of the time while the chemical response of theindividual sensors is not compromised by a too fast temperature change. The PTM e-nose operating principle is evaluated with an array of four commerciallyavailable tin oxide gas sensors, which are modulated with sinusoids of the same amplitude but phase-shifted by 90 degrees. By addressing gas discrimination in the early stages of the transient response and in the steady state, it is demonstrated that the information contained in one entire modulation cycle can be sufficiently recovered from the responses of the individual sensors