Clock Recovery Feedback Control for Frequency Offset Reduction
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Solution Overview
Problem
Current clock and data recovery (CDR) devices with phase-picking circuit architectures struggle to instantly reduce frequency offsets between clock signals at transmitting and receiving terminals, leading to errors in read data.
Innovation Solution
A CDR device comprising a data sampling module, phase detection circuit, frequency estimator, clock generation module, and data recovery module, which employs a feedback control mechanism to adjust clock signals and reduce frequency offsets by generating adjustment signals based on phase and frequency threshold values, thereby improving data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phase-picking circuit architecture with feed-forward circuits is used, then the device complexity is reduced, but the ability to instantly reduce frequency offset deteriorates
Solution Approach 1:
The patent introduces a feedback mechanism where the phase detector detects phase errors between the recovered clock signal and the incoming data, and this error information is fed back to adjust the sampling timing. This closed-loop feedback enables the system to dynamically compensate for frequency offsets and maintain accurate data sampling, resolving the contradiction between simple architecture and effective frequency offset reduction.
2Ease of operation
If feed-forward circuits are used in the phase-picking architecture, then the response speed to frequency offset changes is slow, but the circuit implementation is simpler
Solution Approach 1:
The feedback loop continuously monitors phase errors and immediately adjusts sampling timing in response to frequency offset changes. This real-time feedback mechanism enables rapid response to frequency variations, overcoming the slow response characteristic of feed-forward approaches while maintaining circuit simplicity through efficient use of standard digital logic components.
3Device complexity
If phase-picking circuit architecture is used, then the device structure is simplified, but data sampling accuracy deteriorates when frequency offset is present
Solution Approach 1:
The phase detector and feedback mechanism continuously monitor and correct sampling timing errors caused by frequency offsets. By adjusting the sampling phase based on detected errors, the system maintains high data sampling accuracy despite the simplified phase-picking architecture, effectively resolving the contradiction between structural simplicity and sampling precision.
Data Source
AI summary
A clock and data recovery device includes a data sampling module, a phase detection circuit, a frequency estimator, a clock generation module, and a data recovery module. The data sampling module samples input data according to first clock signals to generate data values, in which phases of the first clock signals are different from one another. The phase detection circuit detects a phase error of the input data according to at least one second clock signal, to generate an error signal. The frequency estimator generates an adjustment signal according to the error signal, a phase threshold value, and a frequency threshold value. The clock generation module generates the first clock signals and the at least one second clock signal according to the adjustment signal and a reference clock signal. The data recovery module generates recovered data corresponding to the input data according to the data values.