DC offset correction for very low intermediate frequency receiver

1. A method for down converting a Radio Frequency (RF) information signal to a baseband information signal, the method comprising:

receiving the RF information signal;

down converting the RF information signal to produce a Very Low Intermediate Frequency (VLIF) information signal at a VLIF and having a DC offset;

down converting the VLIF information signal to produce a baseband information signal having a DC offset component at −VLIF frequency;

low pass filtering the baseband information signal;

producing a DC offset indication for the baseband information signal;

generating a DC offset correction based upon the DC offset indication, the DC offset correction having a DC offset correction component; and

subtracting the DC offset correction at −VLIF frequency from the baseband information signal to substantially remove the DC offset component at −VLIF frequency from the baseband information signal.

2. The method of claim 1 , wherein the VLIF is approximately 100 kHz.

3. The method of claim 2 , wherein the DC offset of the VLIF information signal is introduced by at least one of amplification operations, filtering operations, and down conversion operations.

4. The method of claim 1 , wherein the DC offset indication is produced by correlating a VLIF tone with the baseband information signal across a full RF burst.

5. The method of claim 1 , wherein the DC offset indication is produced by averaging the DC offset of the VLIF information signal across a full RF burst.

6. The method of claim 5 , wherein the full RF burst carries a portion of one of a GPRS data packet or an EDGE data packet.

7. The method of claim 5 , wherein the full RF burst is digitally modulated according to an 8-PSK constellation.

8. The method of claim 5 , wherein the full RF burst is digitally modulated according to a GMSK constellation.

9. A method for down converting a Radio Frequency (RF) information signal to a baseband information signal, the method comprising:

receiving the RF information signal;

in an analog operation, down converting the RF information signal to produce a Very Low Intermediate Frequency (VLIF) information signal at a VLIF and having a DC offset;

in an analog operation, down converting the VLIF information signal to produce a baseband information signal having a DC offset component at −VLIF frequency;

converting the baseband information signal from an analog signal to a digital signal;

in a digital operation, low pass filtering the baseband information signal;

in a digital operation, producing a DC offset indication for the baseband information signal;

in a digital operation, generating a DC offset correction based upon the DC offset indication, the DC offset correction having a DC offset correction component; and

in a digital operation, subtracting the DC offset correction at −VLIF frequency from the baseband information signal to substantially remove the DC offset component at −VLIF frequency from the baseband information signal.

10. The method of claim 9 , wherein the VLIF is approximately 100 kHz.

11. The method of claim 9 , wherein the DC offset indication is produced by averaging the DC offset of the VLIF information signal across a full RF burst.

12. The method of claim 11 , wherein the full RF burst carries a portion of one of a GPRS data packet or an EDGE data packet.

13. The method of claim 11 , wherein the full RF burst is digitally modulated according to an 8-PSK constellation.

14. The method of claim 11 , wherein the hill RF burst is digitally modulated according to a GMSK constellation.

15. A wireless receiver for down converting a Radio Frequency (RF) information signal to a baseband information signal, the wireless receiver comprising:

a local oscillator operable to produce a first local oscillation and a second local oscillation;

a first mixer operable to mix the RF information signal with the first local oscillation to down convert the RF information signal to produce a Very Low Intermediate Frequency (VLIF) information signal at a VLIF and having a DC offset;

a second mixer operable to mix the RF information signal with the second local oscillation to down convert the VLIF information signal to produce a baseband information signal having a DC offset component at −VLIF frequency;

a low pass filter operable to low pass filter the baseband information signal;

a DC offset determination module operable to produce a DC offset indication for the baseband information signal;

a DC offset correction module operable to generate a DC offset correction at −VLIF frequency based upon the DC offset indication; and

a subtraction module operable to subtract the DC offset correction from the baseband information signal to substantially remove a DC offset component at −VLIF frequency from the baseband information signal.

16. The wireless receiver of claim 15 , wherein the VLIF is approximately 100 kHz.

17. The wireless receiver of claim 15 , wherein the DC offset of the VLIF information signal is introduced by at least one of an amplifier, a filter, and the mixer.

18. The wireless receiver of claim 15 , wherein the DC offset indication is produced by averaging the DC offset of the VLIF information signal across a full RF burst.

19. The wireless receiver of claim 18 , wherein the full RF burst carries a portion of one of a GPRS data packet or an EDGE data packet.

20. The wireless receiver of claim 18 , wherein the full RF burst is digitally modulated according to an 8-PSK constellation.

21. The wireless receiver of claim 18 , wherein the full RF burst is digitally modulated according to a GMSK constellation.