Biopotential Measuring Apparatus Artifact Suppression
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Solution Overview
Problem
The prolonged duration of artifact tails in biopotential measurements causes overlap with response waveforms, making it difficult to accurately measure latency and amplitude, thus affecting the examination results.
Innovation Solution
A biopotential measuring apparatus with a stimulating section, lead electrodes, a first amplifier circuit, a high-pass filter, and switches that disconnect electrical connections and adjust gain during stimulation to suppress artifact tails, ensuring accurate measurement by preventing overlap with evoked potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplifier circuit remains connected to the lead electrodes during stimulation, then the response waveform can be continuously monitored, but the artifact tail overlaps with the response waveform causing measurement inaccuracy
Solution Approach 1:
The switch is activated before stimulation begins to disconnect the amplifier from the electrodes, preventing artifact generation in advance. This preliminary action eliminates the artifact tail overlap problem while maintaining continuous monitoring capability through subsequent reconnection.
Solution Approach 2:
The measurement process is divided into distinct phases: a first measurement period before stimulation where the amplifier is connected, a stimulation period where the amplifier is disconnected, and a second measurement period after stimulation where connection is restored. This segmentation allows artifact-free measurement of the response waveform.
2Object-generated harmful factors
If the switch disconnects the amplifier circuit during stimulation to reduce artifact, then the artifact tail is suppressed, but the response waveform measurement may be interrupted
Solution Approach 1:
The system performs preliminary measurement of the response waveform before stimulation occurs while the amplifier is connected. After stimulation and artifact generation, the amplifier is reconnected to continue monitoring. This ensures the response waveform is captured without artifact contamination while maintaining measurement continuity.
Solution Approach 2:
The amplifier connection is periodically adjusted: connected during pre-stimulation and post-stimulation phases for measurement, disconnected during stimulation to prevent artifact. This periodic switching ensures both artifact suppression and continuous response waveform acquisition across multiple cycles.
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 solution effectively suppresses fast and slow artifact tails, allowing for clear measurement of response waveforms, thereby improving the accuracy of biopotential measurements by preventing overlap during stimulation.
Implementation Method 1
a high-pass filter including a capacitor and configured to filter a frequency component of an output from the first amplifier circuit that is no less than a predetermined value
Data Source
AI summary
A stimulating section applies stimulation to a living body. A first lead electrode and a second lead electrode are attached on the living body. A first amplifier circuit amplifies potential difference that is evoked between the first lead electrode and the second lead electrode due to the stimulation. A first switch cancels electrical connection between the first amplifier circuit and each of the first lead electrode and the second lead electrode at least while the stimulation is applied. A high-pass filter includes a capacitor (C) and filters a frequency component of an output from the first amplifier circuit that is no less than a predetermined value. A second amplifier circuit amplifies the output from the first amplifier circuit. A second switch stops charging/discharging of the capacitor (C) and decreases a gain of the second amplifier circuit at least while the first switch cancels the electrical connection.