Sampler reference level, DC offset, and AFE gain adaptation for PAM-N receiver
AssigneeRaambus Inc.
InventorNanyan Wang
Life of this patent
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Abstract
In a PAM-N receiver, sampler reference levels, DC offset and AFE gain may be jointly adapted to achieve optimal or near-optimal boundaries for the symbol decisions of the PAM-N signal. For reference level adaptation, the hamming distances between two consecutive data samples and their in-between edge sample are evaluated. Reference levels for symbol decisions are adjusted accordingly such that on a data transition, an edge sample has on average, equal hamming distance to its adjacent data samples. DC offset may be compensated to ensure detectable data transitions for reference level adaptation. AFE gains may be jointly adapted with sampler reference levels such that the difference between a reference level and a pre-determined target voltage is minimized.
Claims20
A receiver circuit, comprising:
- a first error detection circuit to detect based on a sequence of input symbols, a first sequence of error values between a first reference level and a first desired decision boundary;
- a first combining circuit to combine, over a time window, the first sequence of error values to generate a first cumulative error value;
- a first reference level computation circuit to adjust the first reference level based on the first cumulative error value to generate a first adjusted reference level;
- and
- a decoder circuit to generate output symbols based on a comparison of the sequence of input symbols to the first adjusted reference level.
A method for operating a receiver circuit, comprising:
- detecting based on a sequence of input symbols, by a first error detection circuit, a first sequence of error values between a first reference level and a first desired decision boundary;
- combining over a time window, by a first combining circuit, the first sequence of error values to generate a first cumulative error value;
- adjusting, by a first reference level computation circuit, the first reference level based on the first cumulative error value to generate a first adjusted reference level;
- and
- generating, by a decoder circuit, output symbols based on a comparison of the sequence of input symbols to the first adjusted reference level.
A receiver circuit comprising:
- first error detection means for detecting based on a sequence of input symbols, a first sequence of error values between a first reference level and a first desired decision boundary;
- first combining means for combining over a time window, the first sequence of error values to generate a first cumulative error value;
- first reference level adjusting means for adjusting the first reference level based on the first cumulative error value to generate a first adjusted reference level;
- and
- decoding means for generating output symbols based on a comparison of the sequence of input symbols to the first adjusted reference level.
Dependencies are inferred from the claim text.