Acoustic Temperature Measurement Using Electromagnetic Reference
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Solution Overview
Problem
Current temperature measurement methods, such as those based on sound speed, face challenges in accurately determining fluid temperatures, especially in non-stationary conditions like exhaled breath, due to limitations in direct measurement and sensitivity to ambient cooling.
Innovation Solution
An apparatus and method that determine the time difference between sound arrival and an electromagnetic signal reflected from a vibrating surface, allowing for the calculation of fluid temperature based on sound speed, using chirp mixing and phase-based sampling to improve resolution beyond microphone sampling rate limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sound speed-based temperature measurement is used, then the method is simple, but measurement precision is insufficient especially for non-stationary fluids like exhaled breath
Solution Approach 1:
The patent introduces an intermediary electromagnetic signal as a reference to measure the time difference between sound arrival and electromagnetic signal arrival. This intermediary reference enables precise temperature measurement of non-stationary fluids like exhaled breath by providing a stable timing baseline against which sound propagation can be measured, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent replaces direct mechanical temperature sensing with an acoustic field-based measurement system that uses sound propagation time differences. By substituting mechanical temperature sensors with an acoustic measurement approach using microphones and electromagnetic signals, the system achieves higher precision for non-stationary fluids while maintaining relative simplicity.
2Measurement precision
If direct temperature measurement is used, then measurement precision is high, but the method is sensitive to ambient cooling and lacks accuracy for non-stationary fluids
Solution Approach 1:
The patent converts the harmful effect of ambient cooling sensitivity into a beneficial measurement approach by using sound propagation characteristics, which are inherently resistant to ambient temperature variations. The time difference between sound arrival and electromagnetic signal arrival provides a measurement that reflects the actual fluid temperature without being adversely affected by ambient cooling, effectively turning the limitation of direct measurement into an advantage of acoustic measurement.
3Measurement precision
If microphone sampling rate is used for time difference measurement, then device complexity is low, but resolution is limited
Solution Approach 1:
The patent resolves the resolution limitation by transitioning from a single-dimensional time measurement approach to a two-dimensional measurement space by introducing the electromagnetic signal as a reference dimension. This enables resolution beyond the microphone sampling rate limitation through the time difference calculation between sound and electromagnetic signal arrival, achieving higher precision without proportionally increasing device complexity.
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
Enables accurate and sensitive temperature determination of fluids, including exhaled breath, with reduced impact from ambient cooling and improved resolution, facilitating early detection of medical conditions like asthma and lung cancer.
Implementation Method 1
The speed of sound can be estimated using a difference in the time of arrival of sound at two microphones located at different distances from the sound source. This can be used to determine the temperature of a medium through which the sound passes since speed of sound has a known relationship with temperature.
Implementation Method 2
determining a time difference between arrival at a device of a sound produced by a sound source and an electromagnetic signal reflected from a surface, of a body comprising the sound source
Data Source
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Figure 3~4B
AI summary
According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for: determining a time difference between arrival at a device of a sound produced by a sound source and an electromagnetic signal reflected from a surface, of a body comprising the sound source, which vibrates when the sound is produced; and providing the time difference to enable determination of a fluid temperature based on the speed of sound through the fluid between the body and the device.