Design Consideration and Implementation of Analog Adaptive Filters for Sensor Response Correction

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Description/Abstract

This paper has shown that it is possible to perform effective response compensation of sensors using analog adaptive filter techniques. The case is illustrated by showing how the response of a load cell can be improved to speed up the process of measurement. The load cell is a sensor with an oscillatory output in which the measurand contributes to the response parameters. Thus, a compensation filter needs to track variation in measurand whereas a simple, fixed filter is only valid at one specific load value. It has been shown that the state-variable biquadratic filter provides an accurate and flexible sensor and adaptive compensation filter models. To allow a practical implementation of the adaptive techniques, a novel piecewise linearization technique is proposed in order to vary a floating voltage-controlled resistor in a linear manner over a wide range. Simulation and experimental results are presented, thus showing the viability of the proposed techniques.