ADC digital gain error compensation

A method for compensating gain error of an analog-to-digital converter (ADC) circuit, the method comprising:

• receiving an indication of an external resistance coupled to an input of a combined amplifier and ADC integrated circuit;
• amplifying a received input signal of the combined amplifier and ADC integrated circuit;
• converting the amplified signal to an uncompensated digital signal;
• determining a compensation coefficient using the indication and a stored indication of an input resistance of the combined amplifier and ADC integrated circuit;
• and
• digitally multiplying the compensation coefficient with the uncompensated digital signal to provide an output of the combined amplifier and ADC integrated circuit.

A data acquisition system comprising:

• an electrical apparatus;
• an integrated analog-to-digital converter (ADC) circuit configured to receive a signal from the electrical apparatus and provide a digital representation of the signal;
• and
• wherein the integrated ADC circuit includes:
• an amplifier circuit configured to receive an input signal and to amplify the input signal based on an input resistance of the amplifier and a feedback resistance, and to provide an amplified representation of the input signal;
• and
• an ADC circuit configured to receive an output of the amplifier, to determine a compensation coefficient associated with an additional input resistance coupled to the amplifier, and to provide a compensated digital representation of the amplified representation of the input signal using the compensation coefficient.