Granted Patent B2

US 7,142,137 · App. 11/090,931 · Granted Nov 28, 2006

Abstract

Claims (75)

1. A method of converting an input analog signal to a compensated digital signal, comprising:

converting the input analog signal to an uncompensated digital signal;

inputting the uncompensated digital signal to a distortion model;

generating a modeled distortion signal based on the uncompensated digital signal; and

subtracting the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the distortion model includes a nonlinear coefficient that is empirically determined.

2. A method as recited in claim 1 , wherein the uncompensated digital signal includes an ideal digital signal and a distorted signal.

3. A method as recited in claim 1 , wherein the modeled distortion signal is generated based on a function of the ideal digital signal and the distorted signal.

4. A method as recited in claim 1 , wherein generating a modeled distortion signal includes generating a fractional phase sample.

5. A method as recited in claim 1 , wherein generating a modeled distortion signal includes:

generating a plurality of fractional phase samples by sampling the input analog signal using a plurality of fractional phase sampling clocks;

inputting the plurality of fractional phase samples to the distortion model; and

generating a modeled distortion signal based on the uncompensated digital signal and the plurality of fractional phase samples.

6. A method as recited in claim 1 , wherein generating a modeled distortion signal includes generating a derivative of the input analog signal and inputting the derivative to the distortion model.

7. A method as recited in claim 1 , wherein the distortion modeled implements a nonlinear function having a plurality of nonlinear coefficients, and the plurality of coefficients is determined using a thermometer code.

8. A method as recited in claim 1 , wherein the distortion model is temperature compensated.

9. A method of converting an input analog signal to a compensated digital signal, comprising:

converting the input analog signal to an uncompensated digital signal;

inputting the uncompensated digital signal to a distortion model;

generating a modeled distortion signal based on the uncompensated digital signal; and

subtracting the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein generating a modeled distortion signal includes sampling the input analog signal using a fractional phase sampling clock and inputting the fractional phase sample to the distortion model.

10. A method of converting an input analog signal to a compensated digital signal, comprising:

converting the input analog signal to an uncompensated digital signal;

inputting the uncompensated digital signal to a distortion model;

generating a modeled distortion signal based on the uncompensated digital signal; and

subtracting the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the distortion model includes a low complexity filter configured to implement a nonlinear distortion function.

11. A distortion compensating analog to digital converter (ADC), comprising:

an uncompensated ADC configured to convert an input analog signal to an uncompensated digital signal; and

a compensation module coupled to the uncompensated ADC, configured to:

receive the uncompensated digital signal;

generate a modeled distortion signal based on the uncompensated digital signal; and

subtract the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the compensation module includes a distortion correction module having a distortion model with a nonlinear coefficient that is empirically determined.

12. An ADC as recited in claim 11 , wherein the uncompensated digital signal includes an ideal digital signal and a distorted signal.

13. An ADC as recited in claim 11 , wherein the compensation module is configured to generate the modeled distortion signal based on a function of the ideal digital signal and the distorted signal.

14. An ADC as recited in claim 11 , wherein the compensation module implements a nonlinear function having a plurality of nonlinear coefficients, and the plurality of coefficients is determined using a thermometer code.

15. A distortion compensating analog to digital converter (ADC), comprising:

an uncompensated ADC configured to convert an input analog signal to an uncompensated digital signal; and

a compensation module coupled to the uncompensated ADC, configured to:

receive the uncompensated digital signal;

generate a modeled distortion signal based on the uncompensated digital signal; and

subtract the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the uncompensated ADC includes a primary ADC and the compensation module includes a plurality of auxiliary ADCs.

16. An ADC as recited in claim 15 , wherein:

the primary ADC is configured to generate an L-bit output;

each of the plurality of auxiliary ADCs is configured to generate an m-bit output; and

L is greater than m.

17. An ADC as recited in claim 15 , wherein the plurality of auxiliary ADCs are configured to generate a plurality of fractional phase samples.

18. An ADC as recited in claim 15 , wherein:

the plurality of auxiliary ADCs are configured to:

generate a fractional phase sample by sampling the input analog signal using a fractional phase sampling clock; and

input the fractional phase sample to a distortion correction module.

19. An ADC as recited in claim 15 , wherein the compensation module includes an auxiliary ADC configured to generate a derivative of the input analog signal and input the derivative to a distortion model.

20. A distortion compensating analog to digital converter (ADC), comprising:

an uncompensated ADC configured to convert an input analog signal to an uncompensated digital signal; and

a compensation module coupled to the uncompensated ADC, configured to:

receive the uncompensated digital signal;

generate a modeled distortion signal based on the uncompensated digital signal; and

subtract the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the compensation module includes a low complexity filter configured to implement a nonlinear distortion function.

21. A distortion compensating analog to digital converter (ADC), comprising:

an uncompensated ADC configured to convert an input analog signal to an uncompensated digital signal; and

a compensation module coupled to the uncompensated ADC, configured to:

receive the uncompensated digital signal;

generate a modeled distortion signal based on the uncompensated digital signal, and

subtract the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein compensation module implements a distortion model that is temperature compensated.

22. A computer program product for converting an uncompensated digital signal to a compensated digital signal, the computer program product being embodied in a computer readable medium and comprising computer instructions for:

receiving the uncompensated digital signal;

inputting the uncompensated digital signal to a distortion model;

generating a modeled distortion signal based on the uncompensated digital signal; and

subtracting the modeled distortion signal from the uncompensated digital signal to generate the compensated digital signal;

wherein the distortion model includes a nonlinear coefficient.

Assignments (8)