Dual-Clock Measurement Time Correction for Low-Power Wearables
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Solution Overview
Problem
Wearable sensors face a trade-off between power consumption and measurement time accuracy due to the use of low-power oscillation circuits, which reduces the precision of clock signals, making it difficult to accurately manage measurement times without increasing power consumption.
Innovation Solution
A measurement system that uses a first oscillation circuit for frequent measurements and a second oscillation circuit with higher precision to provide time stamps, combined with a management device that corrects measurement times using time stamps and adjusts the number of measurements to minimize power consumption while maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly accurate clock signal is used for measurement, then the accuracy of the measurement time is improved, but the power consumption increases
Solution Approach 1:
The clock signal generation is segmented into two parts: a low-power oscillation circuit for basic timekeeping and a high-precision oscillation circuit activated only when measurement accuracy is required. This segmentation allows the system to use different clock sources based on operational needs, reducing overall power consumption while maintaining measurement accuracy when necessary.
Solution Approach 2:
The high-precision oscillation circuit is activated periodically or on-demand rather than continuously. The system switches between low-power and high-precision clock modes based on whether measurements are being performed, ensuring accuracy only when needed and minimizing power consumption during non-measurement periods.
2Use of energy by moving object
If an oscillation circuit operating with low power consumption is used, then the power consumption is reduced, but the precision of the clock signal is reduced
Solution Approach 1:
The system dynamically switches between different oscillation circuits based on operational requirements. A low-power oscillation circuit is used during normal operation, while a high-precision oscillation circuit is activated when measurement accuracy is required. This dynamic adaptation allows the system to optimize between power consumption and clock signal precision in real-time.
Solution Approach 2:
The system changes the parameters of the clock signal generation by switching between different oscillation circuits with different characteristics. The low-power circuit provides acceptable precision for general operation, while the high-precision circuit provides accurate timing when measurements are performed, changing the precision parameter based on operational mode.
3Measurement precision
If measurements are performed frequently to improve accuracy, then the measurement precision is improved, but the power consumption increases
Solution Approach 1:
Measurements are performed periodically at optimized intervals rather than continuously. The system determines appropriate measurement timing based on the operational state and activates the high-precision clock only during measurement periods, reducing overall power consumption while maintaining measurement accuracy when data collection occurs.
Data Source
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AI summary
A measurement system (10) includes: a measurement unit (22A) configured to perform measurement a plurality of times on the basis of a first clock signal having a first clock period to obtain a plurality of measurement results; a time stamp provision unit (22B) configured to provide a time stamp indicating a measurement time to each measurement result obtained in the second period among the plurality of measurement results obtained using the measurement unit (22A) the basis of a second clock signal having a second clock period longer than the first clock period and having better period accuracy than the first clock signal; and a measurement time correction unit (32B) configured to correct a measurement time of a measurement result in accordance with a period specified using two time stamps and the number of measurement results obtained during the period. As a result, it is possible to obtain a measurement result to which a measurement time with a small time lag with respect to an actual time is provided with low power consumption.