Clock and data recovery unit
First Claim
1. A clock and data recovery unit for recovering a received serial data bit stream having:
- (a) phase adjustment means for adjustment of a sampling time in the center of a unit interval of the received data bit stream, wherein the phase adjustment means comprises;
(a1) means for generating equidistant reference phase signals;
(a2) a phase interpolation unit which rotates the generated reference phase signals with a predetermined granularity in response to a rotation control signal;
(a3) an oversampling unit for oversampling the received data bit stream with the rotated reference phase signals according to a predetermined oversampling rate;
(a4) a serial-to-parallel-conversion unit which converts the oversampled data bit stream into a deserialized data bit stream with a predetermined decimation factor;
(a5) a binary phase detection unit for detecting an average phase difference between the received serial data bit stream and the rotated reference phase signal by adjusting a phase detector gain depending on an actual data density of the deserialized data bit stream such that the variation of the average phase detection gain is minimized; and
(a6) a loop filter for filtering the detected average phase difference to generate the rotation control signal for the phase interpolation unit;
(b) data recognition means for recovery of the received data bit stream which includes a number of parallel data recognition FIR-Filters, wherein each data recognition FIR-Filter comprises;
(b1) a weighting unit for weighting data samples of the deserialized data bit stream around the sampling time adjusted by the phase adjustment means;
(b2) a summing unit for summing up the weighted data samples; and
(b3) a comparator unit for comparing the summed up data samples with a threshold value to detect the logic value of a data bit within the received serial data bit stream.
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Abstract
A clock and data recovery unit for recovering a received serial data bit stream having: phase adjustment means for adjustment of a sampling time in the center of a unit interval of the received data bit stream, wherein the phase adjustment means comprises means for generating equidistant reference phase signals, a phase interpolation unit, an oversampling unit, a serial-to-parallel-conversion unit, a binary phase detection unit, and a loop filter; and data recognition means for recovery of the received data stream which includes a number of parallel data recognition FIR-Filters, wherein each data recognition FIR-Filter comprises a weighting unit, a summing unit, and a comparator unit.
22 Citations
31 Claims
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1. A clock and data recovery unit for recovering a received serial data bit stream having:
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(a) phase adjustment means for adjustment of a sampling time in the center of a unit interval of the received data bit stream, wherein the phase adjustment means comprises; (a1) means for generating equidistant reference phase signals; (a2) a phase interpolation unit which rotates the generated reference phase signals with a predetermined granularity in response to a rotation control signal; (a3) an oversampling unit for oversampling the received data bit stream with the rotated reference phase signals according to a predetermined oversampling rate; (a4) a serial-to-parallel-conversion unit which converts the oversampled data bit stream into a deserialized data bit stream with a predetermined decimation factor; (a5) a binary phase detection unit for detecting an average phase difference between the received serial data bit stream and the rotated reference phase signal by adjusting a phase detector gain depending on an actual data density of the deserialized data bit stream such that the variation of the average phase detection gain is minimized; and (a6) a loop filter for filtering the detected average phase difference to generate the rotation control signal for the phase interpolation unit; (b) data recognition means for recovery of the received data bit stream which includes a number of parallel data recognition FIR-Filters, wherein each data recognition FIR-Filter comprises; (b1) a weighting unit for weighting data samples of the deserialized data bit stream around the sampling time adjusted by the phase adjustment means; (b2) a summing unit for summing up the weighted data samples; and (b3) a comparator unit for comparing the summed up data samples with a threshold value to detect the logic value of a data bit within the received serial data bit stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. Method for clock and data recovery of a received serial data bit stream comprising the following steps:
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(a) adjusting a sampling time in the center of a unit interval of a received data bit comprising the following substeps; (a1) generating reference phase signals; (a2) rotating said reference phase signals in response to a rotation control signal; (a3) oversampling the received data bit stream with the rotated reference phase signals; (a4) converting an oversampled data bit stream into a deserialized data stream; (a5) detecting an average phase difference between the received serial data bit stream and the rotated phase signals by adjusting a phase detector gain depending on a data density of the deserialized data stream to minimize the variation of an average phase detector gain; (a6) filtering the detected phase difference to generate the rotation control signal; (b) recovering the received data bit stream comprising the following substeps; (b1) weighting data samples of the deserialized data stream around the adjusted sampling time; (b2) summing up the weighted data samples; (b3) comparing the summed up weighted data samples with a threshold value to detect the logic value of a data bit within the serial data bit stream.
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Specification