Impedance measurement system
AssigneeIee International Electronics & Engineering S.A.
InventorLaurent Lamesch
Life of this patent
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Abstract
In an impedance measurement system, a reference impedance (2) to be measured is periodically connected and disconnected by means of switch (3) in parallel to the unknown impedance (1) to be measured. The thus generated amplitude modulation of the measurement current is demodulated, and the amplitude of the demodulated signal is indicative of the reference impedance to be measured. Using a low frequency modulation of the reference impedance enables to measure the impedance of the reference impedance without disconnecting the unknown impedance.
Claims3
An impedance measurement system, in particular a capacitive measurement system, comprising a control and detection circuit operatively connected to an unknown impedance to be measured, said control and detection circuit comprising a first AC signal generator for generating a first AC signal to be operatively applied to said unknown impedance and a first measurement circuit for measuring a current flowing into said unknown impedance, said control and detection circuit further comprising a reference impedance which is operably connectable in parallel to said unknown impedance by means of a switch, wherein said control and detection circuit is configured for periodically connecting and disconnecting said reference impedance in parallel to said unknown impedance, thereby generating a modulated measurement signal, and wherein said control and detection circuit comprises a demodulation circuit for demodulating an amplitude of said modulated measurement signal, the amplitude of the demodulated measurement signal being indicative of said reference impedance.
Dependencies are inferred from the claim text.