System and method for decoupling multiple control loops

• US 7,804,921 B2
• Filed: 05/24/2007
• Issued: 09/28/2010
• Est. Priority Date: 05/30/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hidaka, Yasuo
• Primary Examiner(s): Ahn; Sam K
• Application Number:
  US11/753,164
• Publication Number:
  US 20070280391A1
• Time in Patent Office: 1,223 Days
• Field of Search: 375229-236, 333/18, 333/28.R, 708/300, 708/322, 708/323, 379/340, 379/398
• US Class Current: 375/346
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296
• CPC Class Codes: H04L 25/068 by sampling faster than the nominal bit rate

Abstract

A method for adjusting a signal includes applying a compensation for distortion to a signal to generate an output signal and sampling the output signal to generate data values and boundary values. The method further includes monitoring the sampled values for a first set of data patterns, detecting in the sampled values one of the first set of data patterns, and adjusting the compensation based on the sampled data values and boundary values associated with the detected data pattern in the first set of data patterns. The method further includes, after adjusting the compensation, monitoring the sampled values for a second set of data patterns, detecting in the sampled values one of the second set of data patterns, and adjusting the compensation based on one or more of the sampled data values and boundary values associated with the detected data pattern in the second set of data patterns.

Claims

1. A method for adjusting a signal, comprising:

using an equalizer, applying at least one of a loss compensation for frequency-dependent distortion and an offset compensation for direct current offset (“

DC-offset”

) distortion to a signal before or after the distortion occurs to generate an output signal;

using a clock signal, sampling the output signal at a sampler to generate a plurality of data values and boundary values;

using a controller, monitoring the sampled values for a first set of data patterns;

using the controller, detecting in the sampled values one of the data patterns in the first set of data patterns;

using the controller, adjusting at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the first set of data patterns;

after adjusting at least one of the loss compensation and the offset compensation, monitoring the sampled values for a second set of data patterns using the controller;

using the controller, detecting in the sampled values one of the data patterns in the second set of data patterns; and

using the controller, adjusting at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the second set of data patterns.

2. The method of claim 1, wherein:

each data pattern in the first set of data patterns comprises a high data value at a particular bit in the data pattern; and

each data pattern in the second set of data patterns comprises a low data value at a particular bit in the data pattern, wherein the particular bit comprising the high data value in the first set of data patterns corresponds to the particular bit comprising the low data value in the second set of data patterns.

3. The method of claim 1, wherein:

each data pattern in the first set of data patterns comprises a transition in value and a high data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value; and

each data pattern in the second set of data patterns comprises a transition in value and a low data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value.

4. The method of claim 1, wherein the clock signal is associated with the output signal.

5. A method for adjusting a signal, comprising:

using an equalizer, applying at least one of a loss compensation for frequency-dependent distortion and an offset compensation for direct current offset (“

DC-offset”

) distortion to a signal before or after the distortion occurs to generate an output signal;

using a clock signal, sampling the output signal at a sampler to generate a plurality of data values and boundary values;

using a controller, selecting one of a first set and a second set of data patterns in a random manner;

using the controller, monitoring the sampled data values and boundary values for the selected set of data patterns;

using the controller, detecting in the sampled data values and boundary values a data pattern in the selected set of data patterns;

using the controller, adjusting at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the selected set of data patterns; and

after adjusting at least one of the loss compensation and the offset compensation, selecting one of the first set and the second set of data patterns in a random manner using the controller.

6. The method of claim 5, wherein:

each data pattern in the first set of data patterns comprises a high data value at a particular bit in the data pattern; and

each data pattern in the second set of data patterns comprises a low data value at a particular bit in the data pattern, wherein the particular bit comprising the high data value in the first set of data patterns corresponds to the particular bit comprising the low data value in the second set of data patterns.

7. The method of claim 5, wherein:

each data pattern in the first set of data patterns comprises a transition in value and a high data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value; and

each data pattern in the second set of data patterns comprises a transition in value and a low data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value.

8. The method of claim 5, wherein the clock signal is associated with the output signal.

9. An adaptive equalizer, comprising:

an equalizer configured to apply at least one of a loss compensation for frequency-dependent distortion and an offset compensation for direct current offset (“

DC-offset”

) distortion to a signal before or after the distortion occurs to generate an output signal;

a sampler configured to;

receive the output signal and a clock signal;

using the clock signal, sample the output signal to generate a plurality of data values and boundary values; and

a controller configured to;

monitor the sampled values for a first set of data patterns;

detect in the sampled values one of the data patterns in the first set of data patterns;

adjust at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the first set of data patterns;

after adjusting at least one of the loss compensation and the offset compensation, monitor the sampled values for a second set of data patterns;

detect in the sampled values one of the data patterns in the second set of data patterns; and

adjust at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the second set of data patterns.

10. The adaptive equalizer of claim 9, wherein:

each data pattern in the first set of data patterns comprises a high data value at a particular bit in the data pattern; and

each data pattern in the second set of data patterns comprises a low data value at a particular bit in the data pattern, wherein the particular bit comprising the high data value in the first set of data patterns corresponds to the particular bit comprising the low data value in the second set of data patterns.

11. The adaptive equalizer of claim 9, wherein:

each data pattern in the first set of data patterns comprises a transition in value and a high data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value; and

each data pattern in the second set of data patterns comprises a transition in value and a low data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value.

12. The adaptive equalizer of claim 9, wherein the clock signal is associated with the output signal.

13. An adaptive equalizer, comprising:

an equalizer configured to apply at least one of a loss compensation for frequency-dependent distortion and an offset compensation for direct current offset (“

DC-offset”

) compensation to a signal before or after the distortion to generate an output signal;

a sampler configured to;

receive the output signal and a clock signal; and

using the clock signal, sample the output signal to generate a plurality of data values and boundary values; and

a controller configured to;

select one of a first set and a second set of data patterns in a random manner;

monitor the sampled data values and boundary values for the selected set of data patterns;

detect in the sampled data values and boundary values a data pattern in the selected set of data patterns;

adjust at least one of the loss compensation and the offset compensation applied to the signal based on one or more of the sampled data values and boundary values associated with the detected data pattern in the selected set of data patterns; and

after adjusting at least one of the gain and the offset compensation, select one of the first set and the second set of data patterns in a random manner.

14. The adaptive equalizer of claim 13, wherein:

each data pattern in the first set of data patterns comprises a high data value at a particular bit in the data pattern; and

each data pattern in the second set of data patterns comprises a low data value at a particular bit in the data pattern, wherein the particular bit comprising the high data value in the first set of data patterns corresponds to the particular bit comprising the low data value in the second set of data patterns.

15. The adaptive equalizer of claim 13, wherein:

each data pattern in the first set of data patterns comprises a transition in value and a high data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value; and

each data pattern in the second set of data patterns comprises a transition in value and a low data value 1.5 bits before the boundary value that is between the two successive data values comprising the transition in value.

16. The adaptive equalizer of claim 13, wherein the clock signal is associated with the output signal.