Switching Circuit for Bioelectric Electrode Impedance Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for measuring electrode impedances in bioelectric signal monitoring systems require manual intervention, are unable to detect faults in real-time, and cannot accurately measure impedances of a small number of electrodes individually, disrupting the signal-monitoring process and leading to poor signal quality.
Innovation Solution
An apparatus and method that uses a switching arrangement and controller to determine electrode impedances without disconnecting electrodes from the amplifier, allowing for high-speed impedance measurement of multiple electrodes simultaneously, including a voltage source, switches, and a microcontroller to calculate impedances through various signal paths, enabling continuous monitoring and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual impedance measurement methods are used, then impedance values can be obtained, but the signal-monitoring process is interrupted and real-time fault detection is unable
Solution Approach 1:
The patent implements continuous impedance measurement by integrating the measurement function into the existing amplifier circuit. The amplifier continuously monitors impedance across all electrodes without interruption, allowing both signal monitoring and impedance measurement to occur simultaneously. This eliminates the need to disconnect electrodes or pause monitoring, maintaining continuous useful action for both functions.
Solution Approach 2:
The amplifier is designed to perform multiple functions: it amplifies bioelectric signals while simultaneously measuring impedance across all electrodes. By making the amplifier universal, the system can conduct both signal acquisition and impedance measurement through the same device, enabling continuous operation without interrupting monitoring to perform manual impedance checks.
2Measurement precision
If conventional impedance measurement methods are used, then impedance values can be determined, but individual electrode impedances cannot be accurately measured when few electrodes are present
Solution Approach 1:
The patent measures impedance for each electrode individually by sequentially connecting each electrode to the amplifier input through switching circuitry. This segmentation approach allows the system to isolate and measure each electrode's impedance separately, even when only a few electrodes are present, avoiding the need to measure combined impedances of multiple electrodes as in conventional methods.
Solution Approach 2:
The system changes the measurement parameters by using the amplifier's high-input-impedance characteristic and varying the gain settings to accurately measure individual electrode impedances. By adjusting measurement parameters such as gain and input impedance, the system can accurately determine individual electrode impedances regardless of the total number of electrodes, making it adaptable to small electrode arrays.
3Measurement precision
If electrodes are disconnected for impedance measurement, then impedance values can be obtained, but the mechanical connection stability is compromised
Solution Approach 1:
The patent introduces switching circuitry as an intermediary between the electrodes and the amplifier input. This intermediary allows the system to measure impedance by electronically switching connections without physically disconnecting electrodes from the subject. The switches enable selective connection of each electrode to the measurement circuit while maintaining the stable mechanical attachment of electrodes to the subject's skin.
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
Enables rapid and accurate measurement of electrode impedances, allowing for continuous bioelectric signal monitoring and real-time fault detection, improving signal quality by maintaining electrode connections and providing individual impedance values for each electrode.
Implementation Method 1
a voltage source outputting a voltage signal; a switching arrangement including an input electrically connected with the voltage source for receiving the voltage signal
Implementation Method 2
The electrodes 110, 120 are connected to an EEG amplifier 140. The EEG amplifier 140 amplifies the differential signal between electrodes 110, 120 and produces an output voltage, Vamp
Implementation Method 3
a controller in communication with the switches for opening and closing the switches to establish signal paths between the voltage source and the output, the controller calculating the electrode impedances relative to voltage outputs of the amplifier for each signal path
Data Source
AI summary
Apparatuses and methods are provided for determining electrode impedances of a bioelectric signal-monitoring/recording system that includes an amplifier, and electrodes connected between a subject and the amplifier. An example apparatus includes: a voltage source outputting a voltage signal; a switching arrangement including an input electrically connected with the voltage source for receiving the voltage signal, an output electrically connected with the amplifier and the electrodes, and switches between the input and the output; and a controller in communication with the switches for opening and closing the switches to establish signal paths between the voltage source and the output, the controller calculating the electrode impedances relative to voltage outputs of the amplifier for each signal path.