Patent ID: 7711414

Claim:
A circuit for compensating for an electrode motion artifact, comprising: a carrier signal source to oscillate a carrier signal; a first electrode and a second electrode measuring a voltage or an electric current of a subject to which the carrier signal is introduced; a third electrode introducing the oscillated carrier signal to the subject; a differential amplifier to differentially detect or amplify signals from the first electrode and the second electrode and to output an output signal including an electrocardiogram (ECG) signal and an electrode motion artifact; and an ECG extraction unit to remove the electrode motion artifact signal from the output signal and selectively extracting the ECG signal, wherein the electrode motion artifact signal included in the output signal is modulated by the carrier signal; and the ECG extraction unit extracts: an X signal including the electrode motion artifact signal and the ECG signal within a predetermined frequency band by passing the output signal through a band pass filter (BPF); a Y signal including the electrode motion artifact signal within the predetermined frequency band by passing the output signal through a high pass filter (HPF), selectively identifying the modulated electrode motion artifact signal that is modulated by the carrier signal, demodulating the identified modulated electrode motion artifact signal, and passing the demodulated electrode motion artifact signal through the BPF; and an ECG signal, from the X signal, by using the X signal and the Y signal.