A model of bioelectrode motion artefact and reduction of artefact by amplifier input stage design.

Motion artefact voltages result from mechanical disturbances of bioelectrodes. For dry electrodes the effect of parameters related to the amplifier input stage on the artefact voltage is studied. The results indicate that the artefact voltage consists of two components termed delta R component and delta U component according to the motion-affected element. The delta R component is strongly dependent on the amplifier input resistance Rl and the input bias current lB. For negligible delta R artefacts Rl should be larger than 1 G omega and lB should be less than 50 pA when using bioelectrodes.