Clock Recovery Device for Coherent Receivers

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Solution Overview

Problem

The non-synchronization between the clock of a transmitter and the clock of a receiver in communication systems leads to errors in signal demodulation, which existing clock recovery methods fail to fully address.

Innovation Solution

A clock recovery method that calculates and adjusts for clock sampling errors, signal phase errors, and residual phase errors through polarization demultiplexing and equalizing, involving multiple phases of adjustments to synchronize the sampling clocks, using expressions for phase detection and filtering to refine error compensation values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single-phase phase adjustment is performed based on phase detection, then the device complexity is reduced, but the clock synchronization precision is insufficient to fully address transmitter-receiver clock non-synchronization

Engineering Contradiction:
Improveclock synchronization precisionVSAvoidcomplexity of phase adjustment mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The phase adjustment process is divided into three distinct phases: clock sampling error correction, signal phase error correction, and residual phase error correction. Each phase addresses a specific type of error with dedicated processing steps, allowing precise correction of each error component separately rather than attempting single-phase correction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clock sampling error is corrected in advance before signal phase error correction. By first aligning the sampling clock timing and then proceeding with phase adjustments, the system establishes a proper foundation for subsequent more precise phase corrections to be effective

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple phases of error correction are implemented, then the signal demodulation accuracy is improved, but the processing time and computational complexity increase

Engineering Contradiction:
Improvesignal demodulation accuracyVSAvoidclock recovery processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The three-phase correction process operates periodically in sequence: clock sampling error correction, then signal phase error correction, then residual phase error correction. This structured periodic approach ensures comprehensive error correction while maintaining efficient processing rhythm

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Phase detection continuously monitors the signal and provides feedback on phase errors. This feedback drives the three-phase correction process, allowing the system to automatically adjust and converge on optimal synchronization without manual intervention or excessive processing iterations

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3046300B1Clock recovery method and device
Publication Date: 2020.12.09 ZTE CORP
  • EP3046300B1 patent drawingFigure 1
  • EP3046300B1 patent drawingFigure 2~3
  • EP3046300B1 patent drawingFigure 4~5

AI summary

A clock recovery method and device relate to the field of communication; and address the problem of the non-synchronization between the sampling clock of the transmitter and the sampling clock of the receiver. The method includes calculating a clock sampling error, a signal phase error compensation value, and a residual phase error compensation value based on data obtained after polarization demultiplexing and equalizing; adjusting a sampling clock based on the clock sampling error; performing phase adjustment for the first time based on the signal phase error compensation value; performing phase adjustment for the second time based on the residual phase error compensation value. The technical scheme provided by the embodiments of the present invention is adapted to a coherent data receiver, and achieve the mechanism of the three levels of error compensation.