Design of a gel-less two-electrode ECG monitor

In this paper, an ECG amplifier design, specifically to interface two gel-less electrodes for low-power portable applications, is presented. The goal is to develop a circuit with performance sufficient to extract heart rate information reliably using digital signal processing techniques, when measuring a subject engaging in moderate physical activity (such as walking). This application, having no reference electrode, requires biasing of the input to avoid amplifier saturation, all the while maintaining a sufficiently high common-mode noise rejection. A baseline correction circuit and an isolated circuit ground are included in the proposed design to handle changes in DC voltage drift due to electrode movement as well as to minimize common-mode noise from mains.