System Clock Compensation for Precise PLL Timing Recovery
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Solution Overview
Problem
Existing electronic systems face challenges in achieving precise clock synchronization and frequency translation due to system clock errors, variations in clock propagation delay, and latency issues, which affect the accuracy and reliability of timing distribution in applications like ADCs, DACs, and data communication links.
Innovation Solution
The integration of a system clock compensation circuit within ICs that generates compensation signals based on error models accounting for temperature, vibration, and supply voltage conditions, using a combination of closed-loop and open-loop estimates to correct system clock errors and delay variations, thereby enhancing PLL update rates and phase detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If system clock signals are used to control timing of circuit blocks, then timing control is achieved, but system clock errors cause timing inaccuracies
Solution Approach 1:
The patent implements a feedback mechanism where the actual timing of circuit blocks is monitored and compared against expected timing, and compensation signals are generated based on the measured deviations to correct future timing operations
Solution Approach 2:
The patent changes the parameter of clock signal frequency by generating compensation signals with adjusted frequencies that counteract the systematic errors in the original system clock signal
2Measurement precision
If compensation signals are generated based on multiple operating conditions, then compensation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the compensation function into separate processing stages: temperature compensation, vibration compensation, and supply voltage compensation, where each stage handles a specific environmental factor independently
Solution Approach 2:
The patent creates a universal compensation circuit that handles multiple types of environmental variations (temperature, vibration, supply voltage) through a single integrated system that processes all factors
3Reliability
If closed-loop and open-loop estimates are combined, then system clock error correction is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the closed-loop feedback mechanism (which provides real-time error correction) with the open-loop feedforward mechanism (which provides predictive compensation based on environmental sensors) into a unified compensation signal generation system
Data Source
AI summary
Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.