Adc error correction

A calibration circuit for correcting timing errors introduced by a DAC in a signal path of an ADC, the calibration circuit comprising:

• an input subtraction module configured to subtract an estimated error from an output of the ADC and provide a corrected output;
• a filter module configured to approximate an error transfer function corresponding to the timing errors;
• a correlation module configured to correlate the corrected output with an output from the filter module to extract an error term;
• an integrator module configured to integrate the error term to provide an updated error coefficient;
• and
• a correction module configured to multiply the updated error coefficient with the output from the filter module to provide the estimated error to the input subtraction module.

An ADC circuit comprising:

• an ADC having an input for receiving an analog input signal, an output for providing a digital signal and a signal path between the input and output comprising a DAC;
• and
• a calibration circuit connected to the output of the ADC for correcting timing errors introduced by the DAC, the calibration circuit comprising:
• an input subtraction module configured to subtract an estimated error from an output of the ADC and provide a corrected output;
• a filter module configured to approximate an error transfer function corresponding to the timing errors;
• a correlation module configured to correlate the corrected output with an output from the filter module to extract an error term;
• an integrator module configured to integrate the error term to provide an updated error coefficient;
• and
• a correction module configured to multiply the updated error coefficient with the output from the filter module to provide the estimated error to the input subtraction module.

A method of correcting timing errors introduced by a DAC in a signal path of an ADC with a calibration circuit, the method comprising:

• subtracting with an input subtraction module an estimated error from an output of the ADC and providing a corrected output;
• approximating with a filter module an error transfer function corresponding to the timing errors;
• correlating with a correlation module the corrected output with an output from the filter module to extract an error term;
• integrating with an integrator module the error term to provide an updated error coefficient;
• and
• multiplying with a correction module the updated error coefficient with the output from the filter module to provide the estimated error to the input subtraction module.