Impedance measurement system

摘要

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.