Dynamic Clock Calibration for Wireless Devices
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Solution Overview
Problem
Mobile communication devices face inaccuracies in clock synchronization due to temperature fluctuations, which can lead to incorrect time estimation and synchronization issues when the device wakes up from sleep mode, as existing calibration methods assume gradual temperature changes that may not account for rapid internal temperature variations caused by device design changes.
Innovation Solution
A system and method that dynamically adjust clock calibration by using a temperature sensor to determine a temperature measurement rate and calibration rate based on measured temperature, allowing for more frequent calibration and measurement at higher temperature deviations, with rates stored in a look-up table to minimize processing and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the real time clock is calibrated periodically against the main system clock, then the clock accuracy is improved, but the temperature fluctuation between calibration and correction causes incorrect time estimation
Solution Approach 1:
The patent implements dynamic calibration rate adjustment based on temperature conditions. The system transitions from static periodic calibration to dynamic calibration where the calibration rate is adjusted in real-time according to temperature changes. When temperature deviation exceeds a threshold, the calibration rate is increased to compensate for rapid frequency drift, ensuring reliable synchronization despite temperature fluctuations.
Solution Approach 2:
The patent changes the calibration parameter (calibration rate) based on temperature conditions. The system monitors temperature and adjusts the calibration rate parameter dynamically - using higher calibration rates when temperature changes are detected and lower rates when temperature is stable. This parameter adaptation resolves the contradiction by making the calibration system responsive to environmental conditions that affect clock accuracy.
2Use of energy by moving object
If the main system clock is disabled during sleep mode to conserve battery life, then power consumption is reduced, but the real time clock becomes less accurate due to temperature sensitivity
Solution Approach 1:
The patent adjusts the calibration rate parameter based on temperature conditions to maintain time tracking accuracy while keeping power consumption low. During sleep mode, instead of running the main system clock continuously, the system uses the real time clock with dynamically adjusted calibration. When temperature is stable, calibration occurs at lower rates to save power; when temperature changes rapidly, calibration rate increases to maintain accuracy despite the lower-power sleep mode operation.
3Device complexity
If fixed temperature measurement and calibration rates are used, then device complexity is reduced, but synchronization accuracy deteriorates under rapid temperature changes
Solution Approach 1:
The patent introduces dynamic adjustment of calibration and temperature measurement rates based on actual temperature conditions. The system monitors temperature and automatically adjusts the calibration rate - increasing it when temperature changes indicate potential frequency drift and decreasing it when conditions are stable. This dynamic approach maintains high measurement accuracy without requiring overly complex fixed-rate systems, adapting the calibration behavior to match actual environmental conditions.
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
This approach ensures accurate clock synchronization by accounting for non-linear frequency drift caused by temperature changes, reducing the likelihood of synchronization failures and conserving system resources by adapting to rapid temperature fluctuations.
Implementation Method 1
A temperature sensor is used to determine a temperature measurement rate and a calibration rate
Implementation Method 2
The real time clock typically has lower accuracy and may be sensitive to the operating temperature. To correct this fluctuation, the real time clock is typically calibrated against a reference frequency
Data Source
AI summary
A system for dynamically adjusting clock calibration in a wireless communication device. The system includes a temperature sensor for measuring a temperature, a primary clock coupled to the microprocessor for synchronizing the operation of the wireless communication device and a secondary clock coupled to the microprocessor for tracking time. A signal representing a measured temperature is received. At least one of a temperature measurement rate and a calibration rate based on the measured temperature is determined. A signal representing the at least one of the determined temperature measurement rate and the determined calibration rate is transmitted.