A method of cardiac signal registration through a capacitive coupling between sensors and patient's skin

In this paper a method of cardiac activity registration through a capacitive coupling between sensing electrodes and skin surface is described. An original circuit for input amplifier ultra-high impedance biasing, which allows receiving of the electrocardiogram (ECG) signal through capacitive electrodes, is proposed. The industrial 50/60 Hz interference is suppressed by a notch filter with independent frequency and quality factor adjustment. The output signal from the filter is acquired by an external sound card with 24-bit resolution. The sound card is connected to a personal computer, where ECG signal in digital form is recorded and processed using the Audacity audio editor.