Offset cancellation system for a communication system receiver

1. A receiver circuit for use in a communication system, said receiver circuit comprising:

a forward path including a forward filter, the output of the forward filter being provided to an output device; and

a feedback path including a feedback filter and a mixer, the input of the feedback filter being coupled to the output of the forward filter and the output of the feedback filter being coupled to a first input of the mixer, the second input of the mixer being coupled to a multi-tone signal, and the output of the mixer being coupled to the forward path.

2. The receiver circuit as claimed in claim 1 , wherein said multi-tone signal includes a 0 Hz spectral component.

3. The receiver circuit as claimed in claim 1 , wherein said multi-tone signal provides multiple tones that are equally spaced from one another.

4. The receiver circuit as claimed in claim 1 , wherein said forward filter is a low pass filter.

5. The receiver circuit as claimed in claim 1 , wherein said feedback filter is a low pass filter.

6. A receiver system for use in a communication system, said receiver system comprising:

input means for receiving an input signal;

first low pass filter means for providing channel selection filtering of said input signal and providing an output signal;

second low pass filter means for filtering the output signal and providing an offset output signal; and

mixer means for mixing said offset output signal with a multi-tone signal and providing an offset correction signal to said input means.

7. A receiver system as claimed in claim 6 , wherein said first low pass filter means includes a switched capacitor filter.

8. A receiver system as claimed in claim 6 , wherein said second low pass filter means includes a switched capacitor filter.

9. A receiver system as claimed in claim 8 , wherein said switched capacitor filter sub-samples the output signal.

10. The receiver circuit as claimed in claim 6 , wherein said multi-tone signal includes a 0 Hz spectral component.

11. The receiver circuit as claimed in claim 6 , wherein said multi-tone signal provides multiple tones that are equally spaced from one another.

12. A receiver circuit for receiving radio frequency communication signals, said receiver circuit comprising:

an input filter that receives an input signal;

a combiner that combines the input signal and a feedback signal, and produces a combined input signal;

a channel selection filter that receives the combined input signal and produces an output signal;

a low pass filter that receives the output signal and produces a low pass filtered output signal; and

a mixer that receives a multi-tone signal and the low pass filtered output signal and produces the feedback signal that is provided to the first combiner.

13. The receiver circuit as claimed in claim 12 , wherein said multi-tone signal includes a 0 Hz spectral component.

14. The receiver circuit as claimed in claim 12 , wherein said multi-tone signal provides multiple tones that are equally spaced from one another.

15. A receiver system for use in a communication system, said receiver system comprising:

input means for receiving an input signal;

first low pass filter means for providing channel selection filtering of said input signal and providing an output signal;

second low pass filter means for filtering the output signal and providing an offset output signal; and

means for receiving said offset output signal and for providing a pulsed offset signal to said input means.

16. A receiver system as claimed in claim 15 , wherein said first low pass filter means includes a switched capacitor filter.

17. A receiver system as claimed in claim 15 , wherein said second low pass filter means includes a switched capacitor filter.

18. A receiver system as claimed in claim 17 , wherein said switched capacitor filter sub-samples the output signal.