Bioelectric Electrode Echo Suppression With Reference Signals
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Solution Overview
Problem
Existing differential voltage measuring systems for bioelectric signals, such as EKGs and EEGs, face interference issues due to gaps between electrode shields and the skin, allowing interference signals to couple in and affect measurements.
Innovation Solution
An interference signal measuring facility with additional sensor leads and measuring amplifier circuits connected via resistors to detect electrode reference interference signals, combined with adaptive filter units to generate interference-reduced measurement signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is used to prevent interference signals on electrodes, then interference prevention is improved, but gaps between the shield and skin allow interference coupling
Solution Approach 1:
The interference measurement function is segmented from the main measurement circuit. A separate additional sensor lead is introduced specifically for measuring interference signals on the electrode, while the main sensor lead measures the bioelectric signal. This segmentation allows independent measurement and processing of interference signals without affecting the primary measurement function.
Solution Approach 2:
An intermediate measurement stage is introduced through the additional sensor lead connected via a resistor to the electrode shield. This intermediary structure captures interference signals that couple onto the electrode shield, providing a reference signal that can be used for subsequent interference removal from the main measurement channel.
2Measurement precision
If additional sensor leads and measuring amplifier circuits are added to measure interference signals, then interference measurement capability is improved, but device complexity increases
Solution Approach 1:
The additional sensor lead is connected to a specific local point on the electrode shield through a resistor, creating a localized measurement path for interference signals. This local connection allows interference measurement without requiring a complete redesign of the overall electrode structure or signal path.
Solution Approach 2:
The additional sensor lead serves multiple functions: it measures interference signals on the electrode shield, provides a reference signal for interference removal, and does not significantly interfere with the primary bioelectric signal measurement. This multi-functionality justifies the added complexity by providing multiple benefits from a single structural addition.
3Measurement precision
If adaptive filtering is applied to remove interference signals, then measurement accuracy is improved, but processing complexity increases
Solution Approach 1:
The interference measurement from the additional sensor lead provides feedback information about the interference present on the main measurement channel. This feedback is used by the adaptive filter to dynamically adjust and remove interference signals from the bioelectric measurement, continuously optimizing the signal quality based on real-time interference conditions.
Solution Approach 2:
The interference signal is measured in advance through the additional sensor lead before being subtracted from the main measurement signal. This preliminary measurement allows the adaptive filter to prepare the interference reference signal ahead of time, improving the efficiency and accuracy of the interference removal process.
Data Source
AI summary
An interference signal measuring facility is in a differential voltage measuring system with a signal measuring circuit for measuring bioelectric signals with a number of useful signal paths, each with a sensor electrode. In an embodiment, the interference signal measuring facility has an additional sensor lead for each sensor electrode each of which is electrically connected to a ground connection of a supply lead of a sensor electrode; and a measuring amplifier circuit, for each sensor electrode connected to the additional sensor lead via an electrical resistor, configured to detect a change in electric potential occurring on the sensor lead and to determine an electrode reference interference signal therefrom. Also described is an interference signal compensation facility; a differential voltage measuring system; and a method for generation an interference-reduced biological measurement signal are described.