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US 10,764,093 B2Granted
DFE margin test methods and circuits that decouple sample feedback timing
AssigneeRambus Inc.
InventorsBrian S. Leibowitz, Bruno W. Garlepp
Life of this patent
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Abstract
Described are methods and circuits for margin testing digital receivers. These methods and circuits prevent margins from collapsing in response to erroneously received data, and can thus be used in receivers that employ historical data to reduce intersymbol interference (ISI). Some embodiments allows feedback timing to be adjusted independent of the sample timing to measure the effects of some forms of phase misalignment and jitter.
Claims15
A receiver comprising:
- a data input terminal to receive a stream of input data symbols;
- a first data sampler with first decision-feedback equalization to sample the input data symbols and output a first series of samples, the first decision-feedback equalization based on feedback of the first series of samples;
- a second data sampler with second equalization to sample the input data symbols and output a second series of samples, the second equalization based on an assumption for each preceding data symbol absent consideration of any of the preceding data symbols;
- and
- a comparison circuit to compare the first series of samples with the assumptions of preceding data symbols.
2 more elements
A receiver comprising:
- a data input terminal to receive a stream of input data symbols;
- a first data sampler with first decision-feedback equalization to sample the input data symbols and output a first series of samples, the first decision-feedback equalization based on feedback of the first series of samples;
- a second data sampler with second decision-feedback equalization to sample the input data symbols and output a second series of samples, the second decision-feedback equalization based on an assumption for each preceding data symbol absent consideration of the preceding data symbols;
- a comparison circuit to compare the first series of samples with the assumptions of preceding data symbols, and to compare the first series of samples with the second series of samples;
- and
- an error accumulator coupled to the comparison circuit to accumulate an error signal when a given sample in the first series of samples matches the assumption of the preceding data symbol and does not match a corresponding sample in the second series of samples.
3 more elements
A receiver comprising:
- a data input terminal to receive a stream of input data symbols;
- a first data sampler with first decision-feedback equalization to sample the input data symbols and output a first series of samples, the first decision-feedback equalization based on feedback of the first series of samples;
- a second data sampler with second equalization to sample the input data symbols and output a second series of samples, the second equalization based on an assumption for each preceding data symbol absent consideration of any of the preceding data symbols;
- and
- means for comparing the first series of samples with the assumptions of preceding data symbols.
2 more elements
A receiver comprising:
- a data input terminal to receive a stream of input data symbols;
- a first data sampler with first decision-feedback equalization to sample the input data symbols and output a first series of samples, the first decision-feedback equalization based on feedback of the first series of samples;
- a second data sampler with second equalization to sample the input data symbols and output a second series of samples, the second equalization based on an assumption for each preceding data symbol absent consideration of the preceding data symbols;
- means for comparing the first series of samples with the assumptions of preceding data symbols;
- means for comparing the first series of samples with the second series of sample;
- and
- means for accumulating an error signal when a given sample in the first series of samples matches the assumption of the preceding data symbol and does not match a corresponding sample in the second series of samples.
4 more elements
Dependencies are inferred from the claim text.