A simple active electrode for power line interference reduction in high resolution biopotential measurements

Power-line interference is a major problem in High Resolution Biopotential Measurements, mostly because of capacitive coupling. This paper describes the different coupling paths and the parameters involved in interference reduction. One of the parameters that determine the amplitude of low frequency interference in biopotential recordings is skin-electrode impedance but reducing it, particularly in multichannel measurements is not easy. The authors propose an active electrode (based on commercial electrodes) able to reduce power-line interference by about 20 dB