Transmitter with dynamic equalizer

• US 8,526,532 B2
• Filed: 01/31/2011
• Issued: 09/03/2013
• Est. Priority Date: 01/31/2011
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Warke, Nirmal, Chong, Kian Haur
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US13/017,959
• Publication Number:
  US 20120195359A1
• Time in Patent Office: 946 Days
• Field of Search: 375/229, 375/230, 375/232, 375/259, 375/285, 375/295, 375/296, 375/E7.202, 341/59, 333/18, 333/28.R
• US Class Current: 375/296
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03885 adaptive

Abstract

A method for filtering a signal having a series of symbols to be transmitted using the default coefficients, detecting occurrence of a series of consecutive common symbols followed by a different symbol in the series of symbols and based on detecting the occurrence, changing from the default coefficients to a second set of coefficients.

Claims

1. A method, comprising:

applying default coefficients to a transmit filter;

filtering a signal to be transmitted using the default coefficients, said signal comprising a series of symbols;

detecting occurrence of a series of consecutive common symbols followed by a different symbol; and

based on detecting said occurrence, changing from the default coefficients to a second set of coefficients.

2. The method of claim 1 further comprising changing back to the default coefficients following transmission of the different symbol.

3. The method of claim 1 further comprising changing back to the default coefficients following transmission of a symbol immediately following the different symbol.

4. The method of claim 1 wherein changing from the default coefficients to the second set of coefficients occurs for transmission of the last symbol in the series of consecutive common symbols that precede the different symbol.

5. The method of claim 1 wherein changing from the default coefficients to the second set of coefficients occurs for the last symbol in the series of consecutive common symbols that precede the different symbol with the default coefficients remaining in place for the subsequent two symbols, and the method further comprising changing back to the default coefficients after said subsequent two symbols.

6. The method of claim 1 wherein changing from the default coefficients to the second set of coefficients comprises increasing the coefficient for a post cursor symbol from the post cursor symbol'"'"'s value in the default coefficients.

7. The method of claim 1 wherein changing from the default coefficients to the second set of coefficients comprises decreasing the coefficient for a post cursor symbol from the post cursor symbol'"'"'s value in the default coefficients.

8. A transmitter, comprising:

a dynamic equalizer; and

a digital-to-analog converter coupled to said dynamic equalizer;

wherein said dynamic equalizer is configured to implement a set of default coefficients and then change to a second set of coefficients upon detection of a series of consecutive common symbols followed by a different symbol.

9. The transmitter of claim 8 wherein the dynamic equalizer is configured to change the coefficients back from the second set of coefficients to the default coefficients following transmission of the different symbol.

10. The transmitter of claim 8 wherein the dynamic equalizer is configured to change the coefficients back from the second set of coefficients to the default coefficients following transmission of a symbol immediately following the different symbol.

11. The transmitter of claim 8 wherein the dynamic equalizer is configured to change from the default coefficients to the second set of coefficients for the last symbol in the series of consecutive common symbols that precede the different symbol.

12. The transmitter of claim 8 wherein the dynamic equalizer is configured to change from the default coefficients to the second set of coefficients by increasing the coefficient for a post cursor symbol.

13. The transmitter of claim 8 wherein the dynamic equalizer is configured to change from the default coefficients to the second set of coefficients by decreasing the coefficient for a post cursor symbol.

14. The transmitter of claim 8 wherein the dynamic equalizer is configured to change from the default coefficients to the second set of coefficients for the last symbol in the series of consecutive common symbols that precede the different symbol with the default coefficients remaining in place for the subsequent two symbols and the dynamic equalizer reverts back to the default coefficients after said subsequent two symbols.

15. A serializer/deserializer, comprising:

a parallel-to-serial converter; and

a transmitter coupled to the parallel-to-serial converter, said transmitter configured to implement a set of default filter coefficients and then change to a second set of filter coefficients upon detection of a series of consecutive common symbols followed by a different symbol.

16. The serializer/deserializer of claim 15 wherein the transmitter is configured to change the coefficients back from the second set of coefficients to the default coefficients following transmission of the different symbol.

17. The serializer/deserializer of claim 15 wherein the transmitter is configured to change the coefficients back from the second set of coefficients to the default coefficients following transmission of a symbol immediately following the different symbol.

18. The serializer/deserializer of claim 15 wherein the transmitter is configured to change from the default coefficients to the second set of coefficients for the last symbol in the series of consecutive common symbols that precede the different symbol.

19. The serializer/deserializer of claim 15 wherein the transmitter is configured to change from the default coefficients to the second set of coefficients by increasing the coefficient for a post cursor symbol.

20. The serializer/deserializer of claim 15 wherein the transmitter is configured to change from the default coefficients to the second set of coefficients by decreasing the coefficient for a post cursor symbol.

21. The serializer/deserializer of claim 15 wherein the transmitter is configured to change from the default coefficients to the second set of coefficients for the last symbol in the series of consecutive common symbols that precede the different symbol with the default coefficients remaining in place for the subsequent two symbols and the transmitter reverts back to the default coefficients after said subsequent two symbols.