Methods and systems for adaptive receiver equalization

• US 8,824,538 B2
• Filed: 05/16/2013
• Issued: 09/02/2014
• Est. Priority Date: 04/28/2000
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Buchwald, Aaron, Jiang, Xicheng, Wang, Hui, Baumer, Howard A., Madisetti, Avanindra
• Primary Examiner(s): Puente, Eva
• Application Number:
  US13/895,891
• Publication Number:
  US 20130251020A1
• Time in Patent Office: 474 Days
• Field of Search: 375/232, 375/233
• US Class Current: 375/232
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/0814 the phase shifting device being digitally controlled
• CPC Class Codes: H03L 7/0816 the controlled phase shifter and the frequency- or phase-detection arrangement being connected to a common input
• CPC Class Codes: H03L 7/091 the phase or frequency detector using a sampling device H03L7/087 takes precedence
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 2025/03617 Time recursive algorithms H04L2025/03643 takes precedence
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference
• CPC Class Codes: H04L 25/03885 adaptive
• CPC Class Codes: H04L 7/0025 interpolation of clock signal
• CPC Class Codes: H04L 7/0274 with Costas loop
• CPC Class Codes: H04L 7/0337 Selecting between two or more discretely delayed clocks or selecting between two or more discretely delayed received code signals

Abstract

Methods and systems adaptively equalizing an analog information signal, the method including sampling the analog information signal to provide analog samples including post-transition samples and steady-state samples, and equalizing the analog samples to produce equalized analog samples. The equalizing includes determining a difference between an average post-transition amplitude associated with at least one of the post-transition samples and an average steady-state amplitude associated with at least one of the steady-state samples, and adjusting an equalization coefficient to adjust the difference between the average post-transition amplitude and the average steady-state amplitude.

Claims

1. A method for adaptively equalizing an analog information signal, the method comprising:

sampling the analog information signal to provide analog samples including post-transition samples and steady-state samples; and

equalizing the analog samples to produce equalized analog samples, the equalizing including;

determining a difference between an average post-transition amplitude associated with at least one of the post-transition samples and an average steady-state amplitude associated with at least one of the steady-state samples; and

adjusting an equalization coefficient to adjust the difference between the average post-transition amplitude and the average steady-state amplitude.

2. The method of claim 1, further comprising:

integrating the post-transition samples, the average post-transition amplitude being associated with integrated post-transition samples; and

integrating the steady-state samples, the average steady-state amplitude being associated with integrated steady-state samples.

3. The method of claim 1, further comprising:

accumulating the post-transition samples, the average post-transition amplitude being associated with accumulated post-transition samples; and

accumulating the steady-state samples, the average steady-state amplitude being associated with accumulated steady-state samples.

4. The method of claim 1, wherein the adjusting includes adjusting the difference at a sub-sample rate relative to the sampling the analog information signal.

5. The method of claim 1, wherein the adjusting includes adjusting the difference at an offset of a sub-sample rate relative to the sampling the analog information signal.

6. The method of claim 1, wherein the adjusting includes minimizing the difference between the average post-transition amplitude and the average steady-state amplitude.

7. The method of claim 1, wherein the equalizing includes minimizing inter-symbol interference among the analog samples.

8. The method of claim 1, wherein the sampling includes sampling the analog information signal at a plurality of phases, the method further comprising:

measuring an equalization quality associated with a first phase from among the plurality of phases, wherein

the equalizing includes equalizing the analog samples based on the measured equalization quality.

9. The method of claim 1, wherein a post-transition amplitude represents an amplitude of an equalized analog sample after transitioning from a first amplitude to a second amplitude and before settling to a steady-state value.

10. The method of claim 1, further comprising:

quantizing the equalized analog samples to produce quantized samples;

comparing a multi-level representation of the equalized analog samples with the quantized samples;

performing a least-means-squared operation on a result of the comparing; and

adjusting the equalization coefficient based on a result of the least-means-squared operation.

11. A system, comprising:

a sampler configured to sample an analog information signal to provide analog samples including post-transition samples and steady-state samples; and

an equalizer configured to equalize analog samples to produce equalized analog samples, the equalizer being configured to;

determine a difference between an average post-transition amplitude associated with at least one of the post-transition samples and an average steady-state amplitude associated with at least one of the steady-state samples; and

adjust an equalization coefficient to adjust the difference between the average post-transition amplitude and the average steady-state amplitude.

12. The system of claim 11, wherein the equalizer is further configured to:

integrate the post-transition samples, the average post-transition amplitude being associated with integrated post-transition samples; and

integrate the steady-state samples, the average steady-state sample amplitude being associated with integrated steady-state samples.

13. The system of claim 11, wherein the equalizer is further configured to:

accumulate the post-transition samples, the average post-transition amplitude being associated with accumulated post-transition samples; and

accumulate the steady-state samples, the average steady-state sample amplitude being associated with accumulated steady-state samples.

14. The system of claim 11, wherein the equalizer is configured to adjust the difference at a sub-sample rate relative to the sampling of the analog information signal.

15. The system of claim 11, wherein the equalizer is configured to adjust the difference at an offset of a sub-sample rate relative to the sampling of the analog information signal.

16. The system of claim 11, wherein, to adjust the difference, the equalizer is configured to minimize the difference between the average post-transition amplitude and the average steady-state amplitude.

17. The system of claim 11, wherein the equalizer is configured to minimize inter-symbol interference among the analog samples.

18. The system of claim 11, wherein the sampler is configured to sample the analog information signal at a plurality of phases, and wherein the equalizer is configured to measure an equalization quality associated with a first phase from among the plurality of phases, and to equalize the analog samples based on the measured equalization quality.

19. The system of claim 11, wherein a post-transition amplitude represents an amplitude of an equalized analog sample after transitioning from a first amplitude to a second amplitude and before settling to a steady-state value.

20. The system of claim 11, further comprising:

a quantizer configured to quantize the equalized analog samples to produce quantized samples;

a comparator configured to compare a multi-level representation of the equalized analog samples with the quantized samples;

a least-means-squared module configured to perform a least-means-squared operation on a result of the comparison, wherein the equalizer is configured to adjust the equalization coefficient based on the results of the least-means-squared operation.