Adaptive Channel Filtering for Common-Mode Interference Mitigation
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Solution Overview
Problem
Existing physiological measurement devices struggle with common-mode interference due to slight differences in transfer functions among electrodes, which cannot be fully mitigated by existing methods, leading to noisy and inaccurate measurements.
Innovation Solution
Adapting the digital filter coefficients of each channel based on the characteristics of the vector signal, rather than focusing on channel-specific characteristics, to effectively mitigate common-mode interference, allowing for cost-efficient signal acquisition without requiring additional calibration or RLD techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional common-mode rejection methods (impedance matching, RLD technique) are used, then some interference mitigation is achieved, but common-mode interference cannot be fully cancelled due to transfer function differences between channels
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the coefficients of digital filters in each channel based on the characteristics of the vector signal. Instead of using fixed filter parameters or relying on impedance matching, the system continuously adapts the filter coefficients to optimize common-mode rejection. This allows the system to compensate for transfer function differences between channels and achieve superior interference mitigation while maintaining measurement precision.
2Object-affected harmful factors
If additional calibration techniques or RLD circuits are implemented to improve common-mode rejection, then interference mitigation improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex hardware-based common-mode rejection techniques (such as RLD circuits and impedance matching networks) with a software-based adaptive filtering approach. By using digital signal processing and adaptive coefficient adjustment, the system achieves effective interference mitigation without requiring additional analog circuitry or complex calibration hardware, thereby reducing device complexity and cost while maintaining or improving performance.
Data Source
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AI summary
The present invention relates to a physiological measurement device (11) comprising a plurality of input channels (23), at least two of the input channels including a digital section configured to process a digital signal (d1, d2) representing an analog signal (e1, e2) present at an electrode (13) assigned to the respective channel, a signal combiner (31) configured to calculate at least one vector signal (x) from at least two processed digital signals (df1, df2). To achieve improved common-mode interference mitigation, it is proposed that the digital section of at least one input channel (23) comprise a digital filter (29) configured to filter the digital signal (d1, d2) based on a set of filter coefficients (G1, G2) and a processor (33) configured for calculating the set of filter coefficients (G1, G2) based on the vector signal (x1).