Electrical duobinary soft information receiver for NRZ modulation fiber transmission
AssigneeMaxLinear, Inc.
InventorRainer Strobel
Life of this patent
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Abstract
A receiver circuit is disclosed and is configured to receive an optical signal. The receiver circuit includes a receiving circuit configured to receive the optical signal and convert the optical signal from a duobinary signal format into a binary signal based on a plurality of decision thresholds. The receiver circuit also includes a clock data recovery circuit configured to sample the binary signal per data period at a first time instant based on a predetermined clock data recovery technique, and sample the binary signal per data period at a second time instant offset from the first instant, as well as determine an intermediate sample based on an offset for decoding a transmitted bit sequence according to soft information based on the samples.
Claims11
An electrical duobinary receiver circuit configured to receive an optical signal, comprising:
- a receive circuit configured to perform an electrical duobinary demodulation by processing the optical signal, and converting the optical signal into a binary signal based on three or more decision thresholds with distances therebetween that are unequally spaced from one another;
- and
- a decoder circuitry comprising a log-likelihood ratio circuit configured to process samples from a clock data recovery circuit, and generate a soft information output signal in terms of log-likelihood ratios based on the samples, wherein the samples are based on different bit positions and one or more intermediate positions between the bit positions based on an offset.
A method for an electrical duobinary receiver circuit, the method comprising:
- receiving, via a photo diode, an optical signal;
- converting, via the photo diode, the optical signal to an electrical signal;
- converting the electrical signal to a binary signal based on a plurality of decision thresholds;
- determining, via a clock data recovery circuit, a plurality of samples based on a conditional probability that the plurality of samples are a one bit or a zero bit, and at least one additional intermediate sample based on an offset;
- and
- generating soft information based on the plurality of samples to decode a transmitted bit sequence.
Dependencies are inferred from the claim text.