Granted Patent B2

US 6,885,323 · App. 10/641,332 · Granted Apr 26, 2005

Abstract

Claims (50)

1. A method of correcting for output distortion of an analog to digital converter comprising:

estimating the output distortion;

providing an estimated distortion;

combining an output of the analog to digital converter with the estimated distortion to compensate for the output distortion; and

training a calibration module.

2. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein the output distortion comprises an output distortion of the analog to digital converter.

3. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein the output distortion comprises an output distortion of a circuit that includes the analog to digital converter.

4. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training a calibration module includes training a calibration module adaptively.

5. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein the calibration module comprises a digital signal processor.

6. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein the calibration module comprises a nonlinear filter.

7. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein the calibration module comprises a nonlinear filter; and the nonlinear filter includes at least one linear filter coupled with at least one nonlinear element.

8. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein:

the calibration module comprises a nonlinear filter;

the nonlinear filter includes at least one linear filter coupled with a nonlinear element; and

the nonlinear filter includes delay stages.

9. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training the calibration module includes applying an analog signal to the analog to digital converter and a digital version of the analog signal to the calibration module.

10. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training the calibration module includes applying a first signal to the analog to digital converter and applying a second signal to the calibration module.

11. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training the calibration module includes feeding back an error adaptation signal to adapt the calibration module.

12. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training the calibration module includes feeding back an error adaptation signal to adapt the calibration module using a least mean squared technique.

13. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein:

the calibration module comprises a nonlinear filter; and

training the calibration module includes applying a signal to the calibration module and feeding back an error adaptation signal to adapt a coefficient of the nonlinear filter.

14. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training includes:

selecting a most significant bit output of the analog to digital converter;

applying the selected most significant bit output to the calibration module; and

adapting the calibration module.

15. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training includes:

selecting a most significant bit output of the analog to digital converter;

applying the selected most significant bit output to the calibration module; and

adapting the calibration module to reduce the interference of the selected most significant bit output on a least significant output bit output of the analog to digital converter.

16. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training a calibration module includes training a calibration module using a uniform noise source.

17. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training a calibration module includes training a calibration module using a digital to analog converter.

18. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training a calibration module includes training a calibration module using a digital to analog converter, wherein the digital to analog converter includes fewer output bits than the analog to digital converter.

19. A method of correcting for output distortion of an analog to digital converter as recited in claim 1 , wherein training a calibration module includes training a calibration module using a dynamic element matching digital to analog converter.

20. A distortion correcting analog to digital converter comprising:

a first analog to digital converter configured to provide a first output;

a second analog to digital converter configured to provide a second output having a first output distortion;

a first calibration module coupled to the first analog to digital converter, configured to estimate the first output distortion and provide a first estimated distortion; and

a first combiner for combining the second output with the first estimated distortion to compensate the first output distortion and to provide a first error corrected signal.

21. A distortion correcting analog to digital converter as recited in claim 20 further comprising:

a third analog to digital converter configured to provide a third output having a second output distortion;

a second calibration module coupled to the first analog to digital converter, configured to estimate the second output distortion and provide a second estimated distortion; and

a second combiner for combining the third output with the second estimated distortion to compensate the second output distortion and provide a second distortion corrected signal.

22. A distortion correcting analog to digital converter as recited in claim 20 further comprising:

a third calibration module coupled to the first combiner, configured to estimate a distortion component of the second distortion corrected signal resulting from the first error corrected signal and to provide a third estimated distortion;

a third combiner for combining the second distortion corrected signal with the third estimated signal to provide a third distortion corrected signal.

23. A method of correcting for output distortion of an analog to digital converter, comprising:

determine an estimated distortion in a least significant bit from a most significant bit; and

combining an output of the analog to digital converter with the estimated distortion to compensate for the output distortion;

wherein the determination is made independent of the value of the least significant bit.

Assignments (8)