The isolation mode rejection ratio in bioelectric amplifiers

Abstract

Galvanic isolation of a patient during a bioelectric recording is necessary to ensure the safety of the patient. In a typical measurement situation high interference voltages may be present across the isolation barrier. In this paper the necessity of a very high isolation mode rejection ratio--the ability of the amplifier to suppress feed-through from voltages across the isolation barrier to the output--is argued and a design of a multichannel amplifier with an isolation mode rejection ratio of 160 dB is described.