Development of a two-electrode ECG acquisition system with dynamic interference rejection

The aim of this work was the development of a two electrode electrocardiogram acquisition system with dynamic interference rejection. The developed system is capable of measuring the electrocardiogram using only two electrodes due to its capacity to cancel the differential voltage from the 50 Hz interference signal. This capacity is given by a PLL circuit that generates a signal in phase opposition with the 50 Hz interference. The attenuation of the 50 Hz interference is not static due to the ability of canceling the interfering signal whatever its amplitude. This system proved to have a good performance in the elimination of the 50 Hz interference, particularly when the individual moves or gets closer to power sources with high levels of interference. The system is capable of measuring the electrocardiogram even when there is a small distance between electrodes.