Clock Data Recovery Circuit Frequency Drift Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The accuracy of data recovery in clock and data recovery (CDR) circuits is compromised by frequency drift in the reference clock signal, especially when generated by an oscillator circuit, leading to undesired sampling errors and incorrect data recovery.
Innovation Solution
A CDR circuit with frequency control capability, incorporating a voltage controlled oscillator, frequency detector, and control circuit to detect and adjust the frequency of the clock signal, ensuring accurate data recovery by compensating for frequency drift through voltage signal adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reference clock signal is provided by an oscillator circuit, then the device complexity is reduced, but the frequency drift increases leading to sampling errors
Solution Approach 1:
The patent implements a feedback mechanism where the frequency detector continuously monitors the clock signal frequency and compares it with the target frequency. When frequency drift is detected, the control circuit adjusts the VCO control voltage to correct the frequency deviation, forming a closed-loop feedback system that maintains frequency accuracy without requiring a crystal oscillator.
Solution Approach 2:
The patent dynamically changes the control voltage parameter applied to the VCO based on frequency detection results. The control circuit modifies the VCO control voltage in response to frequency drift conditions, enabling the oscillator to adapt its frequency output and maintain synchronization with the target frequency despite initial drift.
2Ease of operation
If the reference clock frequency drifts, then the ease of operation is maintained, but the data recovery accuracy deteriorates due to sampling errors
Solution Approach 1:
The patent performs preliminary frequency detection and correction actions before data sampling occurs. The frequency detector and control circuit proactively monitor and adjust the clock frequency in advance, ensuring that by the time data sampling takes place, the clock frequency is already corrected and synchronized, thereby preventing sampling errors.
3Reliability
If frequency control capability is added to the CDR circuit, then the frequency accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent merges the frequency control functions (VCO, frequency detector, control circuit) into an integrated frequency synchronization module that works cooperatively with the existing CDR circuit. By combining these functions into a unified control system rather than separate independent components, the patent reduces overall system complexity while achieving frequency drift compensation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for frequency drift in the reference clock, ensuring accurate data recovery by adjusting the clock signal frequency, thereby preventing sampling errors and ensuring correct data recovery.
Implementation Method 1
a voltage controlled oscillator, configured to generate a clock signal according to a voltage signal
Data Source
AI summary
A clock and data recovery circuit includes a voltage controlled oscillator, a frequency detector and a control circuit. The voltage controlled oscillator is configured to generate a clock signal according to a voltage signal. The frequency detector is configured to detect whether increasing a frequency of the clock signal is required according to a plurality of sampling results of the input data signal and accordingly generate a first up control signal. The control circuit is coupled to the voltage controlled oscillator and the frequency detector and configured to adjust the voltage signal according to the first up control signal. The clock and data recovery circuit operates in a data recovery mode after detecting that the frequency of the clock signal is locked, and the frequency detector is configured to detect whether increasing the frequency of the clock signal is required in the data recovery mode.