Continuous time linear equalization and bandwidth adaptation using asynchronous sampling

Patent metadata

Field	Value
Publication number	US-11575549-B2
Application number	US-202217719136-A
Country	US
Kind code	B2
Filing date	Apr 12, 2022
Priority date	Apr 2, 2021
Publication date	Feb 7, 2023
Grant date	Feb 7, 2023

Abstract

Methods and systems are described for generating a time-varying information signal at an output of a continuous time linear equalizer (CTLE), asynchronously sampling a data signal according to a sampling clock having a frequency less than a data rate of the data signal; generating corresponding pattern-verified samples for at least two data patterns, each of the at least two data patterns having a respective frequency content; determining corresponding frequency-specific voltage measurements associated with each of the at least two data patterns based on the corresponding pattern-verified samples of the at least two data patterns; and adjusting an equalization of the data signal based on a comparison of the corresponding frequency-specific voltage measurements.

First claim

We claim:

1. A method comprising:
asynchronously sampling a data signal using a sampler, having a reference decision threshold, according to a sampling clock having a frequency less than a data rate of the data signal to gather statistical eye information at various horizontal offsets throughout the data signaling eye;
detecting decision patterns indicative of either a first data pattern having a high transition density or a second data pattern having a low transition density;
determining an average peak signal value for each decision pattern; and
adjusting an equalization of the data signal based on a comparison of the average peak signal values for each decision pattern.

2. The method of claim 1 , wherein determining the average peak signal value for each decision pattern comprises accumulating pattern-verified samples generated using at least one other sampler having a variable decision threshold, and adjusting the variable decision threshold based on an accumulated ratio of pattern verified samples above the variable decision threshold to pattern verified samples below the variable decision threshold.

3. The method of claim 2 , wherein the variable decision threshold is adjusted until the accumulated ratio reaches a target ratio.

4. The method of claim 2 , wherein the variable decision threshold is adjusted until pattern verified samples above the variable decision threshold are no longer detected.

5. The method of claim 2 , wherein the average peak signal values for each decision pattern are determined using respective samplers of the at least one other sampler having respective variable decision thresholds.

6. The method of claim 2 , wherein the average peak signal values for each decision pattern are determined consecutively using a single sampler of the at least one other sampler.

7. The method of claim 1 , wherein the comparison of the average peak signal values for each decision pattern corresponds determining a ratiometric calculation of the average peak signal values is within a known threshold.

8. The method of claim 7 , wherein the known threshold is approximately a 2:1 ratio of the average peak signal value for the decision pattern indicative of the first data pattern to the average peak signal value for the decision pattern indicative of the second data pattern.

9. The method of claim 1 , wherein the first data pattern having the high transition density corresponds to a “010” data pattern or a “101” data pattern.

10. The method of claim 1 , wherein the second data pattern having the low transition density corresponds to a “111” data pattern or a “000” data pattern.

11. An apparatus comprising:
a sampler having a reference decision threshold configured to asynchronously sample a data signal according to a sampling clock having a frequency less than a data rate of the data signal to gather statistical eye information at various horizontal offsets throughout the data signaling eye;
a pattern detection circuit configured to detect decision patterns indicative of either a first data pattern having a high transition density or a second data pattern having a low transition density;
a controller configured to determine an average peak signal value for each decision pattern and to responsively adjust an equalization of the data signal based on a comparison of the average peak signal values for each decision pattern.

12. The apparatus of claim 11 , wherein the controller comprises an accumulator and at least one other sampler, the accumulator configured to accumulate pattern-verified samples generated using the at least one other sampler having a variable decision threshold, and wherein the controller is configured to adjust the variable decision threshold based on an accumulated ratio of pattern verified samples above the variable decision threshold to pattern verified samples below the variable decision threshold.

13. The apparatus of claim 12 , wherein the controller is configured to adjust the variable decision threshold is until the accumulated ratio reaches a target ratio.

14. The apparatus of claim 12 , wherein the controller is configured to adjust the variable decision threshold until pattern-verified samples above the variable decision threshold are no longer detected.

15. The apparatus of claim 12 , wherein the at least one other sampler comprises two samplers, and wherein the average peak signal values for each decision pattern are determined using respective samplers of the two samplers having respective variable decision thresholds.

16. The apparatus of claim 12 , wherein the at least one other sampler comprises one sampler, and wherein the average peak signal values for each decision pattern are determined consecutively using the one sampler.

17. The apparatus of claim 11 , wherein the controller is configured to determine a ratiometric calculation of the average peak signal values is within a known threshold.

18. The apparatus of claim 17 , wherein the known threshold is approximately a 2:1 ratio of the average peak signal value for the decision pattern indicative of the first data pattern to the average peak signal value for the decision pattern indicative of the second data pattern.

19. The apparatus of claim 11 , wherein the first data pattern having the high transition density corresponds to a “010” data pattern or a “101” data pattern.

20. The apparatus of claim 11 , wherein the second data pattern having the low transition density corresponds to a “111” data pattern or a “000” data pattern.

Assignees

• Kandou Labs SA

Inventors

• Hormati Ali

Classifications

• H04L27/01 Primary

  Equalisers {(baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005)} · CPC title

• H04L25/03885

  adaptive · CPC title

• H04L25/03057

  with a recursive structure (H04L25/03031 takes precedence) · CPC title

• H03F3/45201

  Non-folded cascode stages · CPC title

• H04L7/0079

  Receiver details · CPC title