Patent ID: 8239012

Claim:
A microcontrolled electrocardiographic monitoring circuit with differential voltage encoding, comprising: an input signal path comprising an electrode, a low pass filter, and an amplifier, each connected in-line, the electrode configured to sense an input signal via a conductive surface and the amplifier configured to output a filtered amplified output signal; a microcontroller circuit comprising an input codec, comprising: an analog-to-digital converter connected to the input signal path through an output of the amplifier and configured to convert the filtered amplified output signal into a data stream of discrete digital values; and an encoder configured to determine a differential voltage between a current discrete digital value and a prior discrete digital value in the data stream; and a feedback generator configured to identify a pairing of drive resistor settings matched to each discrete digital value in the data stream and output the drive resistor settings from the microcontroller circuit as a digital feedback signal through a pair of output terminals; and persistent memory connected to the microcontroller circuit via a peripheral serial interface bus, wherein the differential voltages for each of the discrete digital values in the data stream are stored into the persistent memory; an output signal path comprising an electrode and a buffer, each connected in-line, and a pair of drive resistors connected in parallel to an input terminal of the buffer and to the output terminals of the feedback generator, the microcontroller circuit configured to adjust each drive resistor according to the digital feedback signal, and the electrode configured to provide an output signal via a conductive surface.