Chopper-Based Biopotential and Impedance Measurement With 1/f Noise Bypass
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medical devices face challenges in effectively measuring biopotentials and impedances due to noise interference, particularly 1/f noise in amplifiers, which affects the accuracy of biopotential signals and requires separate configurations for biopotential and impedance measurements.
Innovation Solution
A reconfigurable measuring apparatus with choppers and a controller that modulates and demodulates signals based on measurement modes, using frequency signals to bypass noise bands and adjust resistance units for biopotential and impedance measurements, allowing for simultaneous biopotential and impedance measurement with reduced noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate configurations are used for biopotential and impedance measurements, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The measuring apparatus is designed with a single configurable system that can operate in both biopotential measurement mode and impedance measurement mode. The controller selectively activates different choppers and resistance units based on the measurement mode, allowing one device to perform multiple measurement functions without requiring separate dedicated configurations for each mode.
Solution Approach 2:
The apparatus employs dynamic reconfiguration of its internal components through the controller. The first chopper, second chopper, and resistance units are selectively activated or deactivated based on whether biopotential or impedance measurement is required. This dynamic switching capability allows the system to adapt its configuration in real-time, maintaining measurement accuracy for both modes while avoiding the need for permanent separate configurations.
2Object-affected harmful factors
If signal modulation is applied to avoid noise bands, then noise interference is reduced, but device complexity increases
Solution Approach 1:
The first chopper modulates the input signal by periodically switching it, translating the biopotential signal from the low-frequency band where 1/f noise dominates to a higher frequency band. The second chopper then periodically demodulates the amplified signal, recovering the original signal while leaving the amplifier's 1/f noise in the high-frequency band where it can be filtered out. This periodic modulation and demodulation effectively transfers the signal away from the noise band.
Solution Approach 2:
The choppers serve as intermediary devices that facilitate signal translation between frequency bands. Rather than directly measuring the biopotential signal in the noisy low-frequency band, the first chopper acts as an intermediary that shifts the signal to a cleaner high-frequency band for amplification. The second chopper then acts as another intermediary that brings the signal back to the base band while leaving the noise behind.
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 apparatus enables accurate and noise-free measurement of biopotentials and impedances by modulating signals to avoid noise bands and adjusting resistance components, facilitating flexible configuration between biopotential and impedance modes.
Implementation Method 1
a first chopper configured to modulate an input signal
Implementation Method 2
an amplifier configured to amplify an output signal of the first chopper
Implementation Method 3
a second chopper configured to demodulate an output signal of the amplifier
Implementation Method 4
adjusting resistance units for biopotential and impedance measurements
Data Source
AI summary
A reconfigurable measuring apparatus includes a first chopper configured to modulate an input signal, and an amplifier configured to amplify an output signal of the first chopper. The reconfigurable measuring apparatus further includes a second chopper configured to demodulate an output signal of the amplifier, and a controller configured to control the first chopper and the second chopper based on a measurement mode.