Adaptive mismatch compensators and methods for mismatch compensation

An analog-to-digital converter system that compensates for mismatches in converted digital signals during normal operation of the analog-to-digital converter system, comprising:

• a plurality of analog-to-digital converters, each converting an analog input signal to a converted digital signal, the converted digital signals having mismatches;
• a mismatch estimator that monitors at least two mismatched converted digital signals output by the analog-to-digital converters during normal operation and that generates matching parameters indicating an amount of mismatch between the at least two mismatched converted digital signals, the mismatch estimator updating the matching parameters during normal operation of the analog-to-digital converter system;
• and
• a mismatch equalizer that compensates mismatches in the mismatched converted digital signals output by the analog-to-digital converters during normal operation of the analog-to-digital converter system in response to the matching parameters.

A multi-stage analog-to-digital converter that compensates for mismatches in signals during normal operation, comprising:

• a first analog-to-digital converter that converts an analog input signal into a corresponding first stage digital signal;
• an analog delay unit that delays the analog input signal to generate a delayed analog input signal;
• a first mismatch equalizer that compensates mismatches between the delayed analog input signal and a first stage analog signal during normal operation of the multi-stage analog-to-digital converter in response to first matching parameters and that outputs a first stage matched digital signal;
• a first digital-to-analog converter that converts the first stage matched digital signal to the first stage analog signal;
• a subtractor that subtracts the delayed analog input signal from the first stage analog signal to generate a residual analog signal;
• a second analog-to-digital converter that converts the residual analog signal into a corresponding second stage digital signal;
• a second mismatch equalizer that compensates mismatches between the first stage digital signal and the second stage digital signal output by the second analog-to-digital converter during normal operation of the multi-stage analog-to-digital converter in response to second matching parameters and that outputs a second stage matched digital signal;
• and
• a mismatch estimator that monitors the second stage digital signal during normal operation of the multi-stage analog-to-digital converter and that generates the first matching parameters indicating an amount of mismatch between the delayed analog input signal and the first stage analog signal and that generates the second matching parameters indicating an amount of mismatch between the first stage digital signal and the second stage digital signal, the mismatch estimator updating the first and second matching parameters during normal operation of the multi-stage analog-to-digital converter.

A method for compensating mismatches in a system with mismatches, the method comprising:

• monitoring at least two mismatched signals output by the system with mismatches;
• determining amplitudes of the at least two mismatched signals;
• determining frequency content of the at least two mismatched signals;
• and
• during normal operation of the system with mismatches, determining whether the at least two mismatched signals are suitable for an accurate estimation of at least one of:
• gain mismatch, phase mismatch, and DC-offset based on the determined amplitudes and frequency content of the at least two mismatched signals;
• and
• during normal operation of the system with mismatches, estimating at least one of the gain mismatch, the phase mismatch, and the DC-offset between the at least two mismatched signals;
• compensating for mismatches in the at least two mismatched signals based on the estimated at least one of the gain mismatch, the phase mismatch, and the DC-offset between the at least two mismatched signals.