A pulsed system frequency analysis for device characterization and experimental design: Application to porous silicon sensors and extension

Methods of acoustic theory have been applied to signal analysis for improving device characterization on low-frequency timescales. The benefits of this approach include improved measurement sensitivity, isolation of periodic noise sources, and the ability to evaluate the trade-off between the precision and the duration of a measurement to aid the design of an experimental system. A defined gas pulsing technique is combined with FFT signal analysis to allow a sensor gas response to be measured, without saturation, and filtered on a drifting baseline, so as to eliminate false positives and the effects of external noise (as might be associated with pressure, temperature, and humidity variation). Significant advantages can be provided over traditional test-and-measure evaluation schemes, especially near the detection limit of a device, or in the presence of high amplitude noise. The technique, which has been implemented for a porous silicon sensor, shows the potential to improve a number of sensor and experimental systems. The range of applications is discussed.