Inductive Resonator Sensing for Heart-Lung Signal Separation
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Solution Overview
Problem
Existing inductive sensing systems struggle to reliably distinguish between different physiological signals, such as heart and lung activity, and to differentiate these from motion artefacts, leading to incorrect clinical diagnoses and unreliable measurements.
Innovation Solution
An inductive sensing system that utilizes a resonator circuit with a loop antenna to detect both the real and imaginary parts of an additional inductance component induced by electromagnetic signals, employing independent component analysis and a dataset of characteristic relative magnitudes to separate individual signal components corresponding to different physiological sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency-based separation is used to distinguish heart and lung signals, then signal separation is possible under normal conditions, but measurement reliability deteriorates when heart rate and breathing rate frequencies overlap
Solution Approach 1:
The patent transitions from single-frequency analysis to multi-dimensional frequency analysis by examining both positive and negative frequency components. This dimensional expansion allows differentiation of overlapping signals through their distinct spectral signatures in the frequency domain, resolving the contradiction between signal separation and measurement reliability when frequencies overlap.
Solution Approach 2:
The patent applies parameter changes by analyzing multiple frequency parameters simultaneously (positive and negative frequencies) rather than relying on a single frequency measurement. This multi-parameter approach enables reliable distinction between heart and lung signals even when their primary frequencies overlap, maintaining both measurement precision and clinical reliability.
2Object-generated harmful factors
If motion artefact filtering is performed using frequency and waveform analysis, then some artefacts can be removed, but measurement precision deteriorates when artefact characteristics match physiological signals
Solution Approach 1:
The patent extends artefact filtering beyond traditional single-dimensional frequency analysis to multi-dimensional spectral analysis including negative frequencies. This additional dimension provides more discriminatory power to distinguish motion artefacts from physiological signals, reducing false filtering while maintaining measurement precision even when artefact and signal characteristics overlap.
3Device complexity
If a single frequency measurement is used to represent heart rate, then the measurement system is simple, but measurement precision deteriorates when heart rate and breathing rate frequencies overlap
Solution Approach 1:
The patent increases measurement precision by analyzing multiple frequency dimensions (positive and negative frequencies) rather than relying on a single frequency measurement. This multi-dimensional approach provides more information for accurate heart rate determination while maintaining reasonable system complexity through efficient spectral analysis methods.
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
Effectively separates and identifies distinct physiological signals by leveraging the unique relative magnitudes of real and imaginary inductance components, reducing errors and improving the reliability of clinical measurements.
Implementation Method 1
An oscillating primary magnetic field is generated by a generating loop antenna, and this induces, via Faraday's law, eddy currents in the tissue irradiated by the signals. The eddy currents generate a secondary magnetic field.
Implementation Method 2
a resonator circuit comprising a loop antenna; a signal generation means adapted to excite the loop antenna to generate the electromagnetic excitation signals, a signal sensing means adapted to sense said returned signals from the body using the loop antenna, based on detecting variations in electrical characteristics of the resonator circuit
Data Source
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AI summary
An inductive sensing system (8) is adapted to apply electromagnetic excitation signals into a body, the system comprising a resonator circuit (10) incorporating a loop antenna (12). The system senses signals returned back from the body with the same antenna, based on variation in electrical characteristics of the resonator circuit. The system is configured for separating signals received from different physiological sources within the body. This is performed based on detecting in the resonator circuit electrical characteristics indicative of both a real and an imaginary part of an additional inductance component added to the antenna by received electromagnetic signals. The separating the signals from different physiological sources is based on relative magnitudes of said detected real and imaginary inductance components added to the resonator circuit by the returned signals.