Stimulus Standard
Alternating current stimulation of a primary sensing element constitutes the foundational method for inductive and capacitive transducer measurement. Through carrier excitation, a stable alternating voltage or current is applied to a primary coil or electrode to establish the reference electromagnetic field required for position or pressure detection. This sinusoidal drive determines both the resolution floor and the thermal stability of the secondary transducer outputs.
Frequency Response
Selection of the drive signal frequency balances response speed against signal degradation. Higher frequencies allow faster measurement updates but also introduce parasitic capacitive coupling across cables.
Drift Mechanism
Thermal changes in the impedance of the primary windings degrade measurement consistency over time. Heat affects the coil resistance, which induces a phase shift in the resulting signal and alters the apparent scale factor of the sensor. Mitigating this effect requires ratiometric decoding or active compensation from a temperature sensor placed at the primary coil.
Demodulation Constraint
Synchronous rectification of the secondary signal relies on a precise phase alignment with the original excitation source. When the excitation phase drifts due to cable length or temperature variation, the demodulated voltage drops, introducing non-linearities and calibration errors in the final output stage. A phase-locked loop is commonly employed to dynamically track and correct this phase deviation, maintaining high precision across varying environments.
