Analog Motion Artifact Extraction in Biosignal Monitoring Circuits
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Solution Overview
Problem
Existing biosignal monitoring systems face challenges in effectively reducing motion artifacts from biopotential electrical signals, such as ECG, EEG, and EMG, due to changes in the skin-electrode interface during movement, which current techniques like digital adaptive filters and accelerometer-based methods do not adequately address for single-end motion artifact reduction.
Innovation Solution
A biosignal monitoring system comprising a signal processing module, a motion artifact extraction module implemented as an analog domain electronic circuit with a filter network, and a subtraction module, which extracts and attenuates differential mode signals from a first frequency while passing motion artifact signals up to a second frequency, allowing for accurate and efficient single-end motion artifact reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If digital adaptive filters are used to remove motion artifacts, then motion artifact reduction is achieved, but the system complexity and power consumption increase
Solution Approach 1:
The patent replaces complex digital signal processing systems with a simple analog filter circuit. The analog filter uses passive components (resistors, capacitors) and an operational amplifier to achieve motion artifact reduction through frequency-based signal separation, eliminating the need for complex digital algorithms and processors.
Solution Approach 2:
The patent employs a cost-effective analog filter circuit that can be easily manufactured and integrated into biosignal monitoring systems. The use of standard electronic components makes the solution economically viable and suitable for widespread deployment in portable and wearable devices.
2Object-affected harmful factors
If accelerometer-based methods are used for motion artifact removal, then motion detection capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts and filters only the motion artifact frequency components from the biosignal using an analog filter, separating the harmful motion-induced frequencies from the useful physiological signal frequencies. This extraction approach removes motion artifacts without requiring additional sensors or complex processing systems.
3Object-affected harmful factors
If electrode-skin impedance measurement is used as reference signal, then motion artifact extraction is improved, but the measurement precision requirements increase
Solution Approach 1:
The patent segments the biosignal into different frequency components using the analog filter. The filter network separates motion artifact frequencies from physiological signal frequencies, allowing independent processing of each component. This segmentation enables motion artifact removal without requiring precise impedance measurements.
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
The system effectively extracts and subtracts motion artifacts, improving the accuracy and power efficiency of biosignal monitoring by attenuating differential mode signals and representing motion artifacts up to a specific frequency, thereby enhancing the quality of biopotential electrical signals.
Implementation Method 1
a filter network, configured for attenuating differential mode signals of the biopotential electrical signal input from a first frequency, and passing a representation of the motion artifact signal from the biopotential electrical signal input up to a second frequency
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
A biosignal monitoring system (100) for reducing a motion artifact from at least one biopotential electrical signal input (1, 2), comprises: a signal processing module (10), a motion artifact extraction module (9) and a subtraction module (11). The motion artifact extraction module (9) and the signal processing module (10) receive the biopotential electrical signal input (1, 2) and the subtraction module (11) receives both an extracted signal from an output (3, 4) of the motion artifact extraction module (9) and a biopotential electrical signal from an output (5, 6) of the signal processing module (10). The subtraction module (11) is configured for subtracting the extracted signal from the biopotential electrical signal. The motion artifact extraction module (9) is implemented as analog domain electronic circuit and comprises a filter network, configured for attenuating differential mode signals of the biopotential electrical signal input (1, 2) from a first frequency (F1), and passing a representation of the motion artifact signal from the biopotential electrical signal input (1, 2) up to a second frequency (F2) at the output (3, 4) of the motion artifact extraction module (9).