Wearable Electrode Gain Adjustment for Dry-Contact Signal Loss
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Solution Overview
Problem
Traditional electrodes used in wearable devices for physiological signal measurement, such as ECG, often experience signal attenuation due to high electrical impedance at the user-electrode interface, especially when dry electrodes are used.
Innovation Solution
The method involves using a contact detection circuit to apply test signals to the sensing electrode and determine input impedance, allowing for a gain adjustment to be calculated and applied to the measured electrical signals to compensate for signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dry electrodes are used in wearable devices, then ease of operation and device simplicity are improved, but signal quality and measurement precision deteriorate due to high electrical impedance causing signal attenuation
Solution Approach 1:
The system dynamically adjusts the gain parameter of the physiological sensing circuit based on measured input impedance values. When impedance exceeds a threshold (indicating dry electrode contact), the gain is increased to compensate for signal attenuation, thereby maintaining measurement precision while using simple dry electrodes
Solution Approach 2:
The system implements a feedback loop where the contact detection circuit continuously monitors input impedance at the electrode-skin interface, and this impedance information is used to automatically adjust the gain setting of the physiological sensing circuit, ensuring optimal signal quality adapt
2Measurement precision
If gain adjustment is applied to compensate for signal attenuation, then measurement precision is improved, but device complexity increases due to additional control circuits and impedance measurement requirements
Solution Approach 1:
The contact detection circuit and physiological sensing circuit are integrated into a single system where the same hardware components serve dual purposes. The input impedance measurement function is combined with the physiological signal acquisition, allowing gain adjustment without requiring completely separate measurement and control subsystems
Solution Approach 2:
The physiological sensing circuit is designed to perform multiple functions: it can measure both the input impedance (for contact detection) and the physiological signals (such as ECG). This multi-functionality reduces the need for dedicated separate circuits, thereby limiting the increase in device complexity while still enabling gain adjustment
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 improves the accuracy and reliability of physiological measurements by enhancing the signal quality and meeting defined accuracy and reliability criteria, even with dry electrodes.
Implementation Method 1
determining, using the contact detection circuit, an input impedance for the sensing electrode using the test signal
Implementation Method 2
measuring, using a physiological sensing circuit, an electrical signal of the user using the sensing electrode
Data Source
AI summary
Embodiments are directed to methods, devices and systems for determining and applying a gain adjustment to sensed electrical signals. The methods can include operating a device to determine that a user is wearing the wearable electronic device and applying a test signal to a sensing electrode of the wearable device. An input impedance for the sensing electrode can be determined using the test signal. The input impedance and a baseline impedance can be used to determine a gain adjustment. An electrical signal of the user can be measured using the sensing electrode and the gain adjustment can be applied to the electrical signal. A physiological parameter of the user can be determined using the measured electrical signal having the gain adjustment applied.