Methods and apparatus for adjusting a phase of a transmitted signal based on an evaluation of an eye opening in an eye diagram

Patent metadata

Field	Value
Publication number	US-9450848-B1
Application number	US-201514824165-A
Country	US
Kind code	B1
Filing date	Aug 12, 2015
Priority date	Aug 27, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A first network device including modulation, transmit, front end, and phase modules. The modulation module amplitude or frequency modulates a data signal to generate a modulated signal. The transmit module transmits an output signal based on the modulated signal. The front end module obtains a phase of a point in a first cluster of index ratios. Each of the index ratios corresponds to a respective phase of a respective symbol period of the output signal. Each of the index ratios is based on a maximum amplitude, a minimum amplitude or a mean of amplitudes of the output signal over the symbol periods. The amplitudes for each of the means includes a corresponding one of the maximum amplitudes and a corresponding one of the minimum amplitudes. The phase module adjusts a phase of the output signal based on the phase of the point in the first cluster of index ratios.

First claim

What is claimed is:

1. A first network device comprising:
a modulation module configured to amplitude modulate or frequency modulate a data signal to generate a modulated signal;
a transmit module configured to transmit an output signal based on the modulated signal;
a front end module configured to obtain a phase of a point in a first cluster of index ratios, wherein each of the index ratios corresponds to a respective phase of a respective symbol period of the output signal, and wherein each of the index ratios is based on (a) a maximum amplitude of the output signal over the symbol periods, (b) a minimum amplitude of the output signal over the symbol periods, or (c) a mean of a plurality of amplitudes of the output signal over the symbol periods, wherein the plurality of amplitudes for each of the means includes a corresponding one of the maximum amplitudes and a corresponding one of the minimum amplitudes; and
a phase module configured to adjust a phase of the output signal based on the phase of the point in the first cluster of index ratios.

2. The first network device of claim 1 , wherein each of the index ratios is based on (a) the maximum amplitude of the output signal over the symbol periods, (b) the minimum amplitude of the output signal over the symbol periods, and (c) the mean of the plurality of amplitudes of the output signal for the symbol periods.

3. The first network device of claim 1 , further comprising an eye opening module configured to evaluate a vertical eye opening of an eye diagram of the output signal by (i) determining a plurality of index ratios over the symbol periods, wherein the plurality of index ratios includes the first cluster of index ratios, (ii) determining the first cluster of index ratios based on a predetermined threshold, and (iii) selecting the point in the first cluster of index ratios to maximize the vertical eye opening.

4. The first network device of claim 1 , further comprising an eye opening module configured to (i) determine a plurality of index ratios for the output signal, (ii) based on a first predetermined index ratio threshold, determine a minimum phase and a maximum phase for the plurality of index ratios, and (iii) based on the minimum phase and the maximum phase, determine a horizontal eye opening of an eye diagram of the output signal.

5. The first network device of claim 4 , wherein:
the eye opening module is configured to, based on a second predetermined index ratio threshold, determine the first cluster of index ratios and a second cluster of index ratios;
each of the index ratios in the first cluster of index ratios and the second cluster of index ratios are less than or equal to the second predetermined index ratio threshold;
the second predetermined index ratio threshold is less than the first predetermined index ratio threshold; and
the plurality of index ratios includes the first cluster of index ratios and the second cluster of index ratios.

6. The first network device of claim 1 , further comprising an eye opening module configured to, based on a predetermined index ratio threshold, determine the first cluster of index ratios and a second cluster of index ratios,
wherein each of the index ratios in the first cluster of index ratios and the second cluster of index ratios are less than or equal to the predetermined index ratio threshold.

7. The first network device of claim 6 , wherein:
the eye opening module is configured to determine whether the first cluster is wider in phase than the second cluster; and
the phase module is configured to adjust the phase of the output signal based on whether the first cluster is wider in phase than the second cluster.

8. The first network device of claim 7 , wherein:
the eye opening module is configured to determine a mid-point of the wider of the first cluster and the second cluster; and
the phase module is configured to adjust the phase of the output signal based on the mid-point to maximize a vertical eye opening or a horizontal eye opening of an eye diagram of the output signal.

9. A method comprising:
at a first network device, amplitude modulating or frequency modulating a data signal to generate a modulated signal;
based on the modulated signal, transmitting an output signal from the first network device to a second network device;
evaluating an eye opening of an eye diagram of the output signal including obtaining a phase of a point in a first cluster of index ratios, wherein each of the index ratios corresponds to a respective phase of a respective symbol period of the output signal, and wherein each of the index ratios is based on (a) a maximum amplitude of the output signal over the symbol periods, (b) a minimum amplitude of the output signal over the symbol periods, or (c) a mean of a plurality of amplitudes of the output signal over the symbol periods, wherein the plurality of amplitudes for each of the means includes a corresponding one of the maximum amplitudes and a corresponding one of the minimum amplitudes; and
adjusting a phase of the output signal based on the phase of the point in the first cluster of index ratios.

10. The method of claim 9 , wherein each of the index ratios is based on (a) the maximum amplitude of the output signal over the symbol periods, (b) the minimum amplitude of the output signal over the symbol periods, and (c) the mean of the plurality of amplitudes of the output signal for the symbol periods.

11. The method of claim 9 , wherein the evaluating of the eye opening comprises:
determining a plurality of index ratios over the symbol periods, wherein the plurality of index ratios includes the first cluster of index ratios;
determining the first cluster of index ratios based on a predetermined threshold; and
selecting the point in the first cluster of index ratios to maximize the eye opening.

12. The method of claim 9 , further comprising:
determining a plurality of index ratios for the output signal;
based on a first predetermined index ratio threshold, determining a minimum phase and a maximum phase for the plurality of index ratios; and
based on the minimum phase and the maximum phase, determining a horizontal eye opening of the eye diagram of the output signal.

13. The method of claim 12 , further comprising, based on a second predetermined index ratio threshold, determining the first cluster of index ratios and a second cluster of index ratios, wherein:
each of the index ratios in the first cluster of index ratios and the second cluster of index ratios are less than or equal to the second predetermined index ratio threshold;
the second predetermined index ratio threshold is less than the first predetermined index ratio threshold; and
the plurality of index ratios includes the first cluster of index ratios and the second cluster of index ratios.

14. The method of claim 9 , further comprising, based on a predetermined index ratio threshold, determining the first cluster of index ratios and a second cluster of index ratios,
wherein each of the index ratios in the first cluster of index ratios and the second cluster of index ratios are less than or equal to the predetermined index ratio threshold.

15. The method of claim 14 , further comprising determining whether the first cluster is wider in phase than the second cluster,
wherein the phase of the output signal is adjusted based on whether the first cluster is wider in phase than the second cluster.

16. The method of claim 15 , further comprising determining a mid-point of the wider of the first cluster and the second cluster,
wherein the phase of the output signal

Assignees

• Marvell Int Ltd

Inventors

• Wu Songping

Classifications

• H04L27/2035 Primary

  using a single or unspecified number of carriers · CPC title

• H04L43/087 Primary

  Jitter · CPC title

• H04L27/16 Primary

  Frequency regulation arrangements · CPC title