Digital linearizing system

1. A method of compensating for nonlinear distortions in a digital signal, comprising:

receiving the digital signal;

generating a nominal phase shifted signal based on the digital signal;

generating a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtracting the modeled distortion signal from the digital signal; and

generating a compensated signal;

wherein the digital signal includes an undistorted digital component and a distortion component.

2. A method as recited in claim 1 , wherein the digital signal results from an analog input signal restricted to a known region of operation.

3. A method, of compensating for nonlinear distortions in a digital signal, comprising:

receiving the digital signal;

generating a nominal phase shifted signal based of the digital signal;

generating a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtracting th modeled distortion signal from the digital signal; and

generating a compensated signal;

wherein the digital signal results form an analog input signal restricted to a specific Nyquist zone.

4. A method as recited in claim 1 , further comprising generating a modeled distortion signal that is a function of both the undistorted digital component and the distorted component.

5. A method as recited in claim 1 , wherein generating the nominal phase shifted signal includes modulating the digital signal.

6. A method as recited in claim 1 , wherein generating the nominal phase shifted signal includes interpolating the digital signal and taking interpolated values at fractional intervals of a sampling period of the digital signal.

7. A method as recited in claim 1 , wherein generating the nominal phase shifted signal includes up-sampling the digital signal to generate an up-sampled signal, filtering the up-sampled signal and obtaining interpolated values at fractional intervals of a sampling period of the digital signal.

8. A method as recited in claim 1 , wherein:

the digital signal results from an analog input signal restricted to a known region of operation; and

generating the nominal phase shifted signal includes:

up-sampling the digital signal to generate an up-sampled signal;

filtering the up-sampled signal according to the known region of operation; and

obtaining interpolated values at fractional intervals of a sampling period of the digital signal.

9. A method as recited in claim 1 , further comprising generating a derivative of the digital signal; wherein the modeled distortion signal is generated based on the digital signal, the nominal phase shifted signal and the derivative of the digital signal.

10. A method as recited in claim 1 , further comprising generating a nominal phase shifted derivative of the digital signal; wherein the modeled distortion signal is generated based on the digital signal, the nominal phase shifted signal and the nominal phase shifted derivative to the distortion model.

11. A method of compensating for nonlinear distortions in a digital signal, comprising:

receiving the digital signal;

generating a nominal phase shifted signal based on the digital signal;

generating a modeled distortion signal based on the digital and the nominal phase shifted signal;

subtracting the modeled distortion signal from the digital signal; and

generating a compensated signal;

wherein the digital signal is generated by an analog-to-digital converter.

12. A method of compensating for nonlinear distortions in a digital signal, comprising:

receiving the digital signal;

generating a nominal phase shifted signal based on the digital signal;

generating a modeled distortion signal based on the digital and the nominal phase shifted signal;

subtracting the modeled distortion signal from the digital signal; and

generating a compensated signal;

wherein the digital signal is generated by a radio frequency receiver.

13. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted signal based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the digital signal includes an undistorted digital component and a distortion component.

14. A compensating system as recited in claim 13 , wherein the digital signal results from an analog input signal restricted to a known region of operation.

15. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted signal based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the digital signal results from an analog input signal restricted to a specific Nyquist zone.

16. A compensating system as recited in claim 13 , wherein the digital signal includes an undistorted digital component and a distortion component, and the distortion model is further configured to generate a modeled distortion signal that is a function of both the undistorted digital component and the distorted component.

17. A compensating system as recited in claim 13 , wherein generating the nominal phase shifted signal includes modulating the digital signal.

18. A compensating system as recited in claim 13 , wherein generating the nominal phase shifted signal includes interpolating the digital signal and taking interpolated values at fractional intervals of a sampling period of the digital signal.

19. A compensating system as recited in claim 13 , wherein generating the nominal phase shifted signal includes up-sampling the digital signal to generate an up-sampled signal, filtering the up-sampled signal and obtaining interpolated values at fractional intervals of a sampling period of the digital signal.

20. A compensating system as recited in claim 13 , wherein:

the digital signal results from an analog input signal restricted to a known region of operation; and

generating the nominal phase shifted signal includes:

up-sampling the digital signal to generate an up-sampled signal;

filtering the up-sampled signal according to the known region of operation; and

obtaining interpolated values at fractional intervals of a sampling period of the digital signal.

21. A compensating system as recited in claim 13 , further comprising generating a derivative of the digital signal and inputting the derivative of the digital signal to the distortion model.

22. A compensating system as recited in claim 13 , further comprising generating a nominal phase shifted derivative of the digital signal and inputting the nominal phase shifted derivative to the distortion model.

23. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the digital signal is generated be an analog-to-digital converter.

24. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the digital signal is generated by a radio frequency receiver.

25. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the digital signal is generated by a nonlinear system having nonlinear channel characteristics.

26. A compensating system comprising:

an input interface configured to receive a digital signal having nonlinear distortion; and

a distortion model coupled to the interface, configured to:

generate a nominal phase shifted based on the digital signal;

generate a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtract the modeled distortion signal from the digital signal; and

generate a compensated signal;

wherein the distortion model comprises a linear processing module coupled with a nonlinear processing module.

27. A compensating system as recited in claim 26 , wherein the linear processing module is configured to generate the nominal phase shifted signal and the nonlinear processing module is configured to implement a nonlinear distortion function.

28. A compensating system as recited in claim 13 , wherein the distortion model includes a low complexity filter configured to implement a nonlinear distortion function.

29. A compensating system as recited in claim 13 , wherein the distortion modeled implements a nonlinear function that has a linear form with nonlinear coefficients.

30. A compensating system as recited in claim 13 , wherein the distortion modeled implements a nonlinear function having a plurality of coefficients, and the plurality of coefficients are determined using a thermometer code.

31. A compensating system as recited in claim 13 , wherein the distortion model is temperature compensated.

32. A computer program product for compensating for nonlinear distortion in a digital signal, the computer program product being embodied in a computer readable medium and comprising computer instructions for:

receiving the digital signal;

generating a nominal phase shifted signal based on the digital signal;

generating a modeled distortion signal based on the digital signal and the nominal phase shifted signal;

subtracting the modeled distortion signal from the digital signal; and

generating a compensated signal;

wherein the digital signal includes an undistorted digital component and a distortion component.