Adaptive optimum CDR bandwidth estimation by using a kalman gain extractor
US8938043B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2013 |
| Grant date | Jan 20, 2015 |
| Priority date | — |
| Expiry date | Mar 15, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0331
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Exemplary embodiments of the present invention relate to a clock and data recovery (CDR) apparatus with adaptive optimum CDR bandwidth estimation by using a Kalman gain extractor. The Kalman gain extractor includes an off chip digital processor which receives a phase update information from the CDR outputs an estimated optimum Kalman gain obtained by extracting the standard deviation of step sizes of the accumulation jitter from the power spectral density (PSD) of the phase update information, and a on chip digital loop filter consists of a cyclic accumulator which accumulates the phase detector's output, a gain multiplier and a phase interpolator (or DCO) controller. The off chip digital processor includes a storage register, a fast Fourier transform (FFT) processor and an optimum Kalman gain estimator. The storage register stores the phase update information, from which the FFT processor extracts the PSD of the absolute input jitter. The optimum Kalman gain estimator calculates the optimum gain from the PSD of the accumulation jitter. The off chip digital processor may further include a gain calibrator to compensate for the variations in the transition density.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.