AN ALTERNATIVE READ-OUT OF THICKNESS SHEAR MODE RESONATOR BASED CHEMICAL SENSORS IN LIQUID AND GASEOUS SAMPLES

摘要

This work illustrates an alternative method of extracting signals from thickness shear mode resonator sensors. The basic idea consists of modulating the voltage supply of an oscillator circuit driven by a quartz element. The sensor signal can then be obtained measuring the time decay of the output signal in the off state, where some energy, stored in the on state, is released under the form a damping oscillation. It has been experimentally proven that the time decay in the off state can be reproducibly related to the quartz loading by a remarkable sensitivity function. This paper shows most of the results obtained so far by this technique and will discuss the general performance, advantages and disadvantages as well in comparison with the standard frequency measurement technique.