Christian Riesch, Bernhard Jakoby,
"Novel Readout Electronics for Thickness Shear-Mode Liquid Sensors Compensating for Spurious Conductivity and Capacitances"
, in IEEE Sensors Journal, Vol. 7, Nummer 3, Seite(n) 464-469, 3-2007
Original Titel:
Novel Readout Electronics for Thickness Shear-Mode Liquid Sensors Compensating for Spurious Conductivity and Capacitances
Sprache des Titels:
Englisch
Original Kurzfassung:
In this paper, a readout circuit for a thickness
shear-mode (TSM) resonator is presented which can be used
for sensing applications in liquids such as viscosity sensing. The
system features compensation of both spurious capacitances and
conductances in parallel to the resonator. This allows measurements
even in conductive liquids without the need for an elaborate
sealing of the sensor. The influence of the spurious elements is
determined by means of two orthogonal synchronous detectors
and eliminated by active compensation using voltage-controlled
amplifiers (VCAs). Furthermore, the circuit is robust against possible
phase errors. The basic concept is discussed in detail, and a
readout circuit is developed. A prototype is presented, and sample
results are given, demonstrating the feasibility of the approach.
Forschungs-