Adaptation of gain of baseline wander signal

Patent metadata

Field	Value
Publication number	US-9306775-B1
Application number	US-201414484209-A
Country	US
Kind code	B1
Filing date	Sep 11, 2014
Priority date	Sep 11, 2014
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A receiver disposed in a serializer/deserializer (SerDes) system includes a coupling capacitor configured to receive a serial input signal from a transmitter operatively coupled with the receiver via a communication channel established therebetween and to output a capacitance output signal, an equalizer configured to receive a signal including the capacitance output signal having a baseline wander gain subtracted therefrom, a running disparity generator receiving decoded symbols and generating a running disparity signal, and a low-pass filter receiving the running disparity signal and outputting the BLW gain.

First claim

What is claimed is:

1. A receiver disposed in a serializer/deserializer (Ser Des) system, the receiver comprising:
a coupling capacitor configured to receive a serial input signal from a transmitter operatively coupled with the receiver via a communication channel established therebetween and to output a capacitance output signal;
an equalizer configured to receive a signal comprising the capacitance output signal having a baseline wander gain subtracted therefrom, and to output an equalized signal;
a running disparity generator receiving decoded symbols and generating a running disparity signal; and
a low-pass filter receiving the running disparity signal and outputting the baseline wander gain, wherein the coupling capacitor is part of an on-chip alternating current coupling capacitance that causes a high-pass filter to be applied to the received serial input signal and wherein a cut-off frequency of the low-pass filter is equal to that of the high-pass filter at least due to the on-chip alternating current coupling capacitance.

2. The receiver of claim 1 , further comprising a slicer receiving the equalized signal from the equalizer and outputting the decoded symbols.

3. The receiver of claim 2 , wherein the baseline wander gain is generated using the decoded symbols and a direct current (dc) gain of the receiver up to that of the serial input signal.

4. The receiver of claim 2 , wherein the slicer is configured to quantize the equalized signal.

5. The receiver of claim 2 , wherein the slicer is configured to output a transition sample.

6. The receiver of claim 5 , wherein the transition sample comprises sampled values of the capacitance output signal at transitions.

7. The receiver of claim 1 , further comprising an adaptation loop receiving the decoded symbols and outputting a target value for the capacitance output signal.

8. A method for adaptation of baseline wander gain executed by a receiver disposed in a serializer/deserializer (SerDes) system, the method comprising:
receiving, by a coupled capacitor, a serial input signal from a transmitter operatively coupled with the receiver via a communication channel established therebetween;
outputting, by the coupled capacitor, a capacitance output signal;
subtracting a baseline wander gain from the capacitance output signal output by the coupled capacitor prior to inputting the capacitance output signal to an equalizer;
generating a running disparity signal with a running disparity generator that is receiving decoded symbols; and
applying a low-pass filter to the running disparity signal to obtain the baseline wander gain, wherein the coupled capacitor is part of an on-chip alternating current coupling capacitance that causes a high-pass filter to be applied to the received serial input signal and wherein a cut-off frequency of the low-pass filter is equal to that of the high-pass filter leas due to the on-chip alternating current coupling capacitance.

9. The method of claim 8 , further comprising determining an equalized signal given the capacitance output signal having the baseline wander gain subtracted therefrom.

10. The method of claim 9 , further comprising quantizing the equalized signal.

11. The method of claim 8 , further comprising:
determining the baseline wander gain as a function of the running disparity signal.

12. The method of claim 11 , further comprising receiving an equalized signal from the equalizer and outputting the decoded symbols.

13. The method of claim 11 , wherein the baseline wander gain is generated using the decoded symbols and a direct current (dc) gain of the receiver up to that of the serial input signal.

14. The method of claim 8 , further comprising determining a target value for the capacitance output signal using decoded symbols.

15. A computer program product embodied in a non-transitory machine-readable medium having machine-readable program code embodied thereon for performing a method of adaptation of baseline wander gain, the method comprising:
receiving a serial input signal;
outputting a capacitance output signal using the serial input signal;
subtracting a baseline wander gain from the capacitance output signal prior to inputting the capacitance output signal to an equalizer;
generating a running disparity signal using decoded symbols; and
applying a low-pass filter to the running disparity signal to obtain the baseline wander gain, wherein the coupled capacitor is part of an on-chip alternating current coupling capacitance that causes a high-pass filter to be applied to the received serial input signal and wherein a cut-off frequency of the low-pass filter is equal to that of the high-pass filter at least due to the on-chip alternating current coupling capacitance.

16. The computer program product of claim 15 , further comprising determining an equalized signal given the capacitance output signal having the baseline wander gain subtracted therefrom.

17. The computer program product of claim 15 , further comprising:
determining the baseline wander gain as a function of the running disparity signal.

18. The computer program product of claim 17 , further comprising receiving an equalized signal from the equalizer and outputting the decoded symbols.

19. The computer program product of claim 17 , wherein the baseline wander gain is generated using the decoded symbols and a direct current (dc) gain of the receiver up to that of the serial input signal.

20. The computer program product of claim 15 , further comprising determining a target value for the capacitance output signal using decoded symbols.

Assignees

• Avago Technologies General Ip

Inventors

• Kotagiri Shiva Prasad
• Malipatil Amaresh V

Classifications

• H04L25/03019 Primary

  adaptive, i.e. capable of adjustment during data reception · CPC title