Patent attributes
In a biopotential-physiological-phenomena sensing system, an impedance measurement circuit for measuring the impedance of a channel electrode that is applied to a subject's body for sensing a physiological phenomenon includes: an amplifier, a DC-biased power supply with an AC component and a conductive element. The amplifier has a signal input coupled to a channel electrode that is applied to a subject's body and a signal output for providing an output voltage that is representative of a voltage provided at the signal input in accordance with an amplification of the amplifier. The conductive element is coupled between the power supply and the signal input of the amplifier. The AC component of the DC-biased power supply causes a known test current to flow through the channel electrode thereby causing a voltage drop proportional to the impedance of the channel electrode at the input of the amplifier. The impedance of the channel electrode is measured in accordance with the amplifier's output voltage.
