Variable gain amplifier and sampler offset calibration without clock recovery
First Claim
1. A method comprising:
- generating a time-varying information signal at an output of a variable gain amplifier (VGA);
sampling, using a sampler having a vertical decision threshold associated with a target signal amplitude, the time-varying information signal asynchronously to generate a sequence of decisions from varying sampling instants in sequential signaling intervals, the sequence of decisions comprising (i) positive decisions indicating the time-varying information signal is above the target signal amplitude and (ii) negative decisions indicating the time-varying information signal is below the target signal amplitude;
accumulating a ratio of positive decisions to negative decisions; and
generating a gain feedback control signal to adjust a gain setting of the VGA responsive to a mismatch of the accumulated ratio with respect to a target ratio.
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Abstract
Methods and systems are described for generating a time-varying information signal at an output of a variable gain amplifier (VGA), sampling, using a sampler having a vertical decision threshold associated with a target signal amplitude, the time-varying information signal asynchronously to generate a sequence of decisions from varying sampling instants in sequential signaling intervals, the sequence of decisions comprising (i) positive decisions indicating the time-varying information signal is above the target signal amplitude and (ii) negative decisions indicating the time-varying information signal is below the target signal amplitude, accumulating a ratio of positive decisions to negative decisions, and generating a gain feedback control signal to adjust a gain setting of the VGA responsive to a mismatch of the accumulated ratio with respect to a target ratio.
138 Citations
20 Claims
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1. A method comprising:
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generating a time-varying information signal at an output of a variable gain amplifier (VGA); sampling, using a sampler having a vertical decision threshold associated with a target signal amplitude, the time-varying information signal asynchronously to generate a sequence of decisions from varying sampling instants in sequential signaling intervals, the sequence of decisions comprising (i) positive decisions indicating the time-varying information signal is above the target signal amplitude and (ii) negative decisions indicating the time-varying information signal is below the target signal amplitude; accumulating a ratio of positive decisions to negative decisions; and generating a gain feedback control signal to adjust a gain setting of the VGA responsive to a mismatch of the accumulated ratio with respect to a target ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus comprising:
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a variable gain amplifier (VGA) configured to generate a time-varying information signal; a sampler having a vertical decision threshold associated with a target signal amplitude configured to asynchronously sample the time-varying information signal to generate a sequence of decisions from varying sampling instants in sequential signaling intervals, the sequence of decisions comprising (i) positive decisions indicating the time-varying information signal is above the target signal amplitude and (ii) negative decisions indicating the time-varying information signal is below the target signal amplitude; a control filter configured to accumulate a ratio of positive decisions to negative decisions, and to responsively generate a gain feedback control signal to adjust a gain setting of the VGA responsive to a mismatch of the accumulated ratio with respect to a target ratio. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification