An improved method to continuously monitor the electrode-skin impedance during bioelectric measurements.
In bioelectric recordings the electrode-skin impedance mismatch reduces the common mode rejection ratio (CMRR) of the amplifier. For this reason, the impedance of each individual electrode-skin contact is usually measured prior to a recording. The measurement circuit itself degrades the CMRR and is switched off during the bioelectric recording. In this work we present a new method that allows to monitor the electrode-skin impedance in a continuous way without reducing the CMRR of the amplifier. The new method is based on an additional common mode signal which is superimposed on the bioelectric signal.
Degen
Thomas
T
Department of Electrical Engineering, HSR University of Applied Sciences Rapperswil, SG 8640 Rapperswil, Switzerland. thomas.degen@ieee.org
Loeliger
Teddy
T
D000669:Amplifiers, Electronic; D016477:Artifacts; D017097:Electric Impedance; D004566:Electrodes; D004568:Electrodiagnosis / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012879:Skin Physiological Phenomena