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US 9,071,320 B1Granted
Gain calibration for a timing error detector
AssigneePMC-Sierra, Inc.
InventorsWilliam D. Warner, Anthony Eugene Zortea
Life of this patent
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Abstract
Apparatus and methods calibrate and control detector gain in a Mueller-Muller timing detector. A Mueller-Muller circuit obtains timing information for a received signal in which the receiving device samples the signal once per baud period.
Claims28
A method of adjusting gain, the method comprising:
- in a main signal path that includes a timing error detector (TED):
- receiving first soft symbol samples that are sampled from a received signal at a rate of one sample per baud period;
- processing the first soft symbol samples to generate a main error signal;
- scaling the main error signal with a scaling factor to generate a scaled main error signal, wherein the scaled main error signal is used for clock recovery;
- in a secondary signal path that includes a secondary TED:
- receiving second soft symbol samples from the received signal that are sampled at the rate of one sample per baud period, wherein the second soft symbol samples are deliberately offset in time with a known offset from the first symbol samples;
- processing the second soft symbol samples to generate a secondary error signal;
- scaling the secondary error signal with the scaling factor to generate a scaled secondary error signal, wherein the scaled secondary error signal is not used for clock recovery;
- comparing the scaled main error signal and the scaled secondary error signal;
- and
- adaptively adjusting the scaling factor based on the comparison between the scaled main error signal and the scaled secondary error signal such that the scaling of the scaled main error signal is adjusted.
8 more elements
An apparatus comprising:
- a main signal path of a receiver comprising:
- a first timing error detector (TED), wherein the first TED is configured to process first soft symbol samples to generate a main error signal, wherein the first soft symbol samples are sampled from a received signal at a rate of one sample per baud period;
- and
- a multiplier configured to multiply the main error signal with a scaling factor to generate a scaled main error signal, wherein the scaled main error signal is used for clock recovery;
- a secondary signal path of the receiver comprising:
- a second TED configured to process the second soft symbol samples to generate a secondary error signal, wherein the second soft symbol samples are sampled from the received signal at the rate of one sample per baud period, wherein the second soft symbol samples are deliberately offset in time with a known offset from the first symbol samples;
- a multiplier configured to multiply the secondary error signal with the scaling factor to generate a scaled secondary error signal, wherein the scaled secondary error signal is not used for clock recovery;
- and
- a gain calibration circuit configured to compare the scaled main error signal and the scaled secondary error signal and to adaptively adjust the scaling factor based on the comparison between the scaled main error signal and the scaled secondary error signal.
6 more elements
An apparatus for adjusting gain, the apparatus comprising:
- a main signal path that includes a timing error detector (TED), the main signal path comprising:
- a first timing error detector (TED), wherein the first TED is configured to process first soft symbol samples to generate a main error signal, wherein the first soft symbol samples are sampled from a received signal at a rate of one sample per baud period;
- and
- a means for scaling the main error signal with a scaling factor to generate a scaled main error signal, wherein the scaled main error signal is used for clock recovery;
- a secondary signal path that includes a secondary TED, the secondary signal path comprising:
- a second TED configured to process the second soft symbol samples to generate a secondary error signal, wherein the second soft symbol samples are sampled from the received signal at the rate of one sample per baud period, wherein the second soft symbol samples are deliberately offset in time with a known offset from the first symbol samples;
- a means for scaling the secondary error signal with the scaling factor to generate a scaled secondary error signal, wherein the scaled secondary error signal is not used for clock recovery;
- a means for comparing the scaled main error signal and the scaled secondary error signal;
- and
- a means for adaptively adjusting the scaling factor based on the comparison between the scaled main error signal and the scaled secondary error signal such that the gain of the first TED is adjusted.
7 more elements
Dependencies are inferred from the claim text.