Biopotential Signal Detection With Electrode Impedance Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bio-signal monitoring devices struggle to accurately measure biopotential signals due to impedance changes caused by movement artifacts and sweat accumulation, which they cannot fully compensate for, and fail to identify which electrodes are displaced or shunted.
Innovation Solution
The apparatus uses two skin electrodes and a reference electrode, with variable controlled resistance loads and a controller that adjusts these loads and the gain in response to simultaneous changes in signal amplitudes, allowing for compensation of movement artifacts and sweat effects by generating distinct alternating signals and performing time-frequency analysis to differentiate between signal origins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bio-signal monitoring devices are used, then the device complexity is low, but the measurement precision deteriorates due to impedance changes caused by movement artifacts and sweat accumulation
Solution Approach 1:
The patent segments the monitoring system into multiple independent functional modules: a biopotential signal monitoring module for measuring the primary signal, an impedance signal monitoring module for detecting impedance changes, and a control module for coordinating their operation. This segmentation allows each module to specialize in specific tasks, improving overall measurement precision while managing device complexity through modular design
Solution Approach 2:
The patent introduces an intermediary impedance measurement mechanism that acts as a mediator between the electrodes and the biopotential signal measurement system. By measuring impedance changes separately and using this information to compensate for movement artifacts and sweat effects, the system improves biopotential signal accuracy without directly complicating the core measurement pathway
2Reliability
If no compensation mechanism is used, then the device complexity is low, but the reliability deteriorates due to inability to compensate for movement artifacts and sweat effects
Solution Approach 1:
The patent implements a feedback mechanism where the control module continuously monitors impedance signal changes and uses this information to adjust and compensate for movement artifacts and sweat accumulation effects on the biopotential signal. This closed-loop feedback system maintains signal quality consistency over time, improving reliability while managing complexity through intelligent control algorithms
Solution Approach 2:
The patent performs preliminary impedance measurement and analysis before the impedance changes significantly affect the biopotential signal quality. By detecting impedance trends early and preparing compensation parameters in advance, the system maintains signal reliability proactively rather than reactively, reducing the complexity of real-time emergency compensation
3Measurement precision
If electrodes are placed on skin surface, then the ease of operation is high, but the measurement precision deteriorates due to impedance changes from external factors
Solution Approach 1:
The patent converts the harmful effect of sweat accumulation and movement-induced impedance changes into a beneficial measurement opportunity. By using the impedance signal monitoring module to detect these changes and the control module to compensate for them, the system transforms previously detrimental factors into useful information that enhances measurement precision through active compensation
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 solution enables accurate and continuous measurement of biopotential signals by effectively compensating for impedance changes caused by movement artifacts and sweat accumulation, maintaining signal quality and reliability over time.
Implementation Method 1
a first signal generator for generating a first alternating signal connected to the first terminal, a second signal generator for generating a second alternating signal connected to the second terminal
Implementation Method 2
a first circuitry configured for measuring the biopotential signal from the first and the second terminal, a fourth circuitry connected to the output of the first circuitry and configured to apply a variable controlled gain
Implementation Method 3
a first variable controlled resistance load connected to the first terminal, a second variable controlled resistance load connected to the second terminal, the controller being configured: to control the first variable controlled resistance load and the second variable controlled resistance load
Implementation Method 4
a fourth circuitry connected to the output of the first circuitry and configured to apply a variable controlled gain to the output signal of the first circuitry
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and apparatus (1) for measuring a biopotential signal together with impedance changes using electrodes (100, 101 and 102) on a subject's skin and for compensating for such impedances to increase accuracy and usability of such devices for short-and long-term monitoring of biosignals.