Granted Patent B2

US 8,787,430 · App. 12/558,781 · Granted Jul 22, 2014

Abstract

Claims (60)

1. A transmission system, comprising:

a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:

a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;

a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;

an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;

an equalizer coupled to receive the digitized signals; and

a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter, and

an offset block coupled between the down-converter and the filter, the offset block offsetting the in-phase signal and the quadrature signal such that signals output from the analog-to-digital converter averages zero.

2. A transmission system, comprising:

a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:

a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;

a filter coupled to receive the in-phase and the quadrature signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;

an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;

an amplifier coupled between the filter and the analog-to-digital converter, the amplifier amplifying an in-phase filtered signal from the in-phase filter and a quadrature filter signal from the quadrature filter such that the analog-to-digital converter is filled;

an equalizer coupled to receive the digitized signals; and

a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter,

wherein an in-phase gain of the amplifier and a quadrature gain of the amplifier are adaptively chosen in an automatic gain controller.

3. The system of claim 2 , wherein the automatic gain controller sets the in-phase gain and the quadrature gain based on the digitized signals from the analog to digital converters.

4. The system of claim 3 , wherein the in-phase gain and the quadrature gain are equal.

5. A transmission system, comprising:

a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:

a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;

a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band and including an in-phase filter filtering the in-phase signal and a quadrature filter filtering the quadrature signal;

an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals, the analog-to-digital converter including a first analog-to-digital converter coupled to receive signals from the in-phase filter and a second analog-to-digital converter coupled to receive signals from the quadrature filter;

an equalizer coupled to receive the digitized signals;

a correction circuit coupled between the analog-to-digital converter and the equalizer, the correction circuit including an adjustment to correct phases between the in-phase signal and the quadrature signal; and

a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter,

wherein a small portion of one of the in-phase signal and the quadrature signal are added to the opposite one of the in-phase signal and the quadrature signal.

6. The system of claim 5 , wherein a second portion of the opposite one of the in-phase signal and the quadrature signal is added to the opposite one of the in-phase signal and the quadrature signal.

7. The system of claim 6 , wherein the small portion and the second portion are adaptively chosen.

8. The system of claim 7 , wherein the small portion is a function of in-phase and quadrature output signals from the correction circuit.

9. The system of claim 7 , wherein the second portion is a function of the ratio between in-phase and quadrature signals from the correction circuit.

10. The system of claim 5 , wherein a phase rotator circuit is coupled between the analog-to-digital converter and the equalizer.

11. The system of claim 10 , wherein a parameter of the phase rotator circuit is adaptively chosen.

12. A transmission system, comprising:

a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:

a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;

a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band;

an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;

an equalizer coupled to receive the digitized signals;

a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter;

an amplifier coupled between the equalizer and the trellis decoder; and

a quadrature correction coupled between the amplifier and the trellis decoder.

13. The system of claim 12 , wherein an offset circuit is coupled between the quadrature correction and the trellis decoder.

14. The system of claim 13 , wherein a parameter of the offset circuit is adaptively chosen.

15. The system of claim 12 , wherein an in-phase gain and a quadrature gain of the amplifier are adaptively chosen from error signals calculated from sliced values.

16. The system of claim 15 , wherein the sliced values are determined from input signals to the trellis decoder.

17. The system of claim 12 , wherein a parameter of the quadrature correction is adaptively chosen.

18. A transmission system comprising:

a plurality of receivers, each of the plurality of receivers receiving signals from one of a plurality of transmission bands, at least one of the plurality of receivers comprising:

a down-converter that converts an input signal from the one of the plurality of transmission bands to a base band, the down-converter creating an in-phase signal and a quadrature signal, the in-phase signal being the input signal multiplied by a cosine function at the frequency of the one of the plurality of transmission bands and the quadrature signal being the input signal multiplied by a sine function at the frequency of the one of the plurality of transmission bands;

a filter coupled to receive signals from the down-converter, the filter substantially filtering out signals not in the base band;

an analog-to-digital converter coupled to receive signals from the filter and generate digitized signals;

an equalizer coupled to receive the digitized signals, wherein the equalizer is a complex equalizer executing a transfer function, the transfer function having parameters C k x (j) and C k y (j), where j is an integer; and

a trellis decoder coupled to receive signals from the equalizer and generate recreated data, the recreated data being substantially the same data transmitted by a corresponding transmitter.

19. The system of claim 18 , wherein the center parameters C k x (0) and C k y (0) are fixed.

20. The system of claim 19 , wherein C k x (0) is one and C k y (0) is zero.

21. The system of claim 19 , wherein the parameters C k x (−1) and C k y (−1), are fixed.

22. The system of claim 21 , wherein the parameter C k x (−1) is about −0.3125.

23. The system of claim 21 , wherein the parameter C k y (−1) is about −0.015625.

Assignments (8)