Clock Signal Calibration Using Reconstructed Reference Timing
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Solution Overview
Problem
Existing methods for calibrating clock signals in microcontrollers and IoT devices lack precision and accuracy, particularly in low-cost and small-size electronic devices, necessitating improved calibration techniques to ensure reliable synchronization and security.
Innovation Solution
A method involving a high-speed clock signal is used to sample and align a reference clock, allowing for self-compensation of synchronization errors, with the option to perform periodic or event-triggered calibration, reducing costs and complexity by saving silicon area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional clock calibration methods are used, then device complexity and power consumption are reduced, but clock signal precision and synchronization accuracy deteriorate
Solution Approach 1:
The calibration system uses the device's own high-speed clock to calibrate itself by sampling the reference clock and generating alignment signals, eliminating the need for external calibration equipment and reducing system complexity while maintaining high precision
Solution Approach 2:
The system performs calibration periodically or upon specific events (such as hacking attempt detection) rather than continuously, reducing power consumption and operational complexity while maintaining clock signal accuracy when needed
2Reliability
If continuous clock calibration is performed, then synchronization accuracy is improved, but power consumption increases
Solution Approach 1:
The calibration process is executed periodically or triggered by specific events rather than continuously, maintaining synchronization reliability while significantly reducing power consumption during normal operation
3Measurement precision
If high-precision calibration components are added, then clock calibration accuracy is improved, but silicon area and device cost increase
Solution Approach 1:
The high-speed clock serves multiple functions: it operates as both the device operational clock and the calibration reference source, eliminating the need for separate dedicated calibration components and reducing silicon area
Solution Approach 2:
The system creates a digital copy of the reference clock by sampling it with the high-speed clock and reconstructing it through logic circuits, enabling precision calibration without physical duplication of hardware components
Data Source
AI summary
A method includes providing a reference clock signal having a reference period, providing a sampling clock signal having a sampling clock period shorter than the reference period of the reference clock signal, measuring the first subperiod as a first ratio of the first subperiod to the period of the sampling clock signal, measuring the second subperiod as a second ratio of the second subperiod to the period of the sampling clock signal, detecting a starting edge of a clock signal having a clock period greater than the reference period, producing a reconstructed reference signal based on the first ratio, the second ratio, and the detected starting edge, comparing the clock period of the clock signal with a period of the reconstructed reference signal to obtain a differential signal indicating a difference therebetween, and providing the differential signal to user circuitry for calibrating the clock signal.