| abstract |
A microcontrolled electrocardiographic monitoring circuit (10) with feedback control is provided. An input signal path (23) includes an electrode (12a), a low pass filter (13a), and an amplifier (13b) connected in-line. The electrode (12a) senses an input signal and the amplifier (13b) outputs a filtered amplified output signal. A microcontroller circuit (11) includes an input codec, analog-to-digital converter (14), and feedback generation module. The analog-to-digital converter (14) converts the filtered amplified output signal into a data stream (31) of discrete digital values. The feedback module identifies a pairing of drive resistor settings matched to each discrete digital value, which are output as a digital feedback signal. The output signal path (24) includes an electrode (12b) and a buffer (20) connected in-line. A pair of drive resistors (21a, 21b) is connected in parallel to an input terminal of the buffer (20) and to the output terminals of the feedback module. Each drive resistor is adjusted according to the digital feedback signal, and the electrode (12b) provides an output signal. |