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Size Constraint to Limit Interference in DRL-Free Single-Ended Biopotential Measurements



In this work, it is shown that small, battery-powered wireless devices are so robust against electromagnetic interference that single-ended amplifiers can become a viable alternative for biopotential measurements, even without a Driven Right Leg (DRL) circuit.


A power line interference analysis is presented for this case showing that this simple circuitry solution is feasible, and presenting the constraints under which it is so: small-size devices with dimensions less than 40 mm × 20 mm.


A functional prototype of a two-electrode wireless acquisition system was implemented using a single-ended amplifier. This allowed validating the power-line interference model with experimental results, including the acquisition of electromyographic (EMG) signals. The prototype, built with a size fulfilling the proposed guidelines, presented power-line interference voltages below 1.2 µVPP when working in an office environment.


It can be concluded that a single-ended biopotential amplifier can be used if a sufficiently large isolation impedance is achieved with small-size wireless devices. This approach allows measurements with only two electrodes, a very simple front-end design, and a reduced number of components.

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This work was supported by the National Scientific and Technical Research Council (CONICET, Argentina) under Grant PIP-0323; by the La Plata National University (UNLP, Argentina) under Grants I-254 and I-014; and by the National Agency for Scientific and Technological Promotion (ANPCyT, Argentina) under Grant PICT-2018-03747.

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All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by all authors. The first draft of the manuscript was written by VAC and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Correspondence to Valentín A. Catacora.

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Catacora, V.A., Guerrero, F.N. & Spinelli, E.M. Size Constraint to Limit Interference in DRL-Free Single-Ended Biopotential Measurements. J. Med. Biol. Eng. 42, 332–340 (2022).

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  • Biopotential amplifier
  • Electromagnetic interference
  • Single-ended system
  • Two-electrode measurement