Adaptive composite analog to digital converter

1. A distortion correcting analog to digital converter (ADC) system, comprising:

a plurality of ADCs configured to convert an analog signal to a plurality of digital ADC outputs, wherein:

the plurality of ADCs are configured to generate a composite signal based on the plurality of ADC outputs;

there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal; and

an adaptive module coupled to the plurality of ADCs, wherein:

the adaptive modules includes an adaptive filter having a filter response; and

the adaptive module is configured to adaptively adjust the filter response to reduce the distortion in the composite signal.

2. The system of claim 1 , wherein the offset includes a phase offset.

3. The system of claim 1 , wherein adaptively adjusting the filter response includes adaptively adjusting a filter phase delay.

4. The system of claim 1 , wherein the offset includes an amplitude offset.

5. The system of claim 1 , wherein adaptively adjusting the filter response includes adaptively adjusting a filter coefficient.

6. The system of claim 1 , wherein the adaptation is based at least in part on a cost function.

7. The system of claim 6 , wherein the cost function measures energy of the distortion.

8. The system of claim 6 , wherein the cost function is determined based on a cross-correlation function of a phase adjusted signal and a mirror-modulated signal.

9. The system of claim 8 , wherein the mirror-modulated signal is generated based at least in part on a mirroring sequence.

10. The system of claim 1 , wherein the adaptive filter includes a finite impulse response (IIR) filter.

11. The system of claim 1 , wherein adaptively adjusting the filter response includes adjusting a first filter coefficient while keeping a second filter coefficient constant.

12. The system of claim 1 , wherein the adaptive module is one of a plurality of adaptive modules, and the plurality of adaptive modules are arranged in a cascade configuration.

13. A method of generating a distortion corrected digital signal, comprising:

converting an analog signal to a plurality of digital signals;

generating a composite signal based on the plurality of digital signals; wherein there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal;

sending the composite signal to an adaptive module that includes an adaptive filter having a filter response; and

adaptively adjust the filter response to reduce the distortion in the composite signal.

14. The method of claim 13 , wherein adaptively adjusting the filter response includes adaptively adjusting a filter phase delay.

15. The method of claim 13 , wherein adaptively adjusting the filter response includes adaptively adjusting a filter coefficient.

16. The method of claim 13 , wherein the adaptation is based at least in part on a cost function.

17. The method of claim 16 , wherein the cost function measures energy of the distortion.

18. The method of claim 16 , further comprising determining the cost function, based on a cross-correlation function of a phase adjusted signal and a mirror-modulated signal.

19. The method of claim 18 , further comprising generating a mirror-modulated signal based at least in part on a mirroring sequence.

20. The method of claim 13 , wherein adaptively adjusting the filter response includes adjusting a first filter coefficient while keeping a second filter coefficient constant.

21. An adaptive module, comprising:

an interface configured to receive a composite signal that is a combination of a plurality of ADC outputs; and

an adaptive filter coupled to the interface; wherein:

there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal;

the adaptive filter has a filter response; and

the adaptive filter is configured to adapt the filter response to reduce the distortion; wherein

adapting the filter response includes adaptively adjusting a filter phase delay.

22. An adaptive module, comprising:

an interface configured to receive a composite signal that is a combination of a plurality of ADC outputs; and

an adaptive filter coupled to the interface; wherein:

there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal;

the adaptive filter has a filter response; and

the adaptive filter is configured to adapt the filter response to reduce the distortion; wherein

adapting the filter response to reduce the distortion is based at least in part on a cost function that measures energy of the distortion.

23. A method of generating a distortion corrected digital signal, comprising:

receiving a composite signal that is a combination of a plurality of digital signals;

wherein there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal; and

adapting a filter response of an adaptive filter to reduce the distortion; wherein

adapting the filter response includes adaptively adjusting a filter phase delay.

24. A method of generating a distortion corrected digital signal, comprising:

receiving a composite signal that is a combination of a plurality of digital signals;

wherein there is an offset between a first one of the plurality of ADC outputs and a second one of the plurality of ADC outputs, the offset causing distortion in the composite signal; and

adapting a filter response of an adaptive filter to reduce the distortion; wherein

adapting the filter response to reduce the distortion is based at least in part on a cost function that measures energy of the distortion.