EMG Circuit Offset Removal for ADC Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromyography (EMG) systems face challenges in effectively processing action potential voltages to produce accurate EMG signals, often introducing voltage offsets that affect signal symmetry and resolution, leading to reduced ADC resolution and incomplete waveform representation.
Innovation Solution
The EMG circuit comprises a difference circuit to create an EMG signal with a non-zero voltage offset, a rectification circuit to rectify the signal, and an integration circuit to produce a first EMG output signal, with additional offset removal mechanisms like high-pass filters to center the signal and remove inherent offsets, ensuring full ADC range utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the difference circuit creates an EMG signal based on the difference between two action potential voltages, then the EMG signal is generated, but a voltage offset is introduced that centers the signal about a non-zero voltage
Solution Approach 1:
The patent extracts and removes the voltage offset from the EMG signal using an offset removal circuit. This circuit specifically targets and eliminates the non-zero voltage offset introduced by the difference circuit, allowing the signal to be centered about zero voltage while maintaining full ADC resolution. The offset removal process separates the unwanted DC component from the useful AC EMG signal.
Solution Approach 2:
The patent changes the voltage parameter of the EMG signal by dynamically adjusting the offset voltage. The offset removal circuit modifies the signal's voltage level to center it about zero, transforming the signal from being centered about a non-zero voltage to being centered about zero, thereby optimizing the utilization of the ADC's full voltage range.
2Reliability
If the rectification circuit rectifies the EMG signal about a non-zero voltage, then the signal is rectified, but the voltage offset remains and reduces ADC resolution
Solution Approach 1:
The patent applies preliminary action by removing the voltage offset from the EMG signal before the rectification process. The offset removal circuit is positioned upstream of the rectification circuit, ensuring that the signal is centered about zero voltage prior to rectification. This preliminary offset removal prevents the offset from interfering with the rectification process and preserves full ADC resolution throughout subsequent processing stages.
3Measurement precision
If additional offset removal circuits are added to remove inherent offsets, then signal accuracy is improved, but circuit complexity increases
Solution Approach 1:
The patent merges multiple offset removal functions into a single integrated offset removal circuit. This circuit simultaneously handles both the offset introduced by the difference circuit and any inherent offsets present in the action potential voltages. By combining these functions, the patent achieves comprehensive offset removal without proportionally increasing circuit complexity, as the single circuit performs multiple offset correction tasks.
Data Source
AI summary
According to one aspect of the present disclosure, an electromyography (EMG) circuit comprises a difference circuit, rectification circuit, offset removal circuit, and integration circuit. The difference circuit is configured to create an EMG signal based on a difference between two action potential voltages. Creation of the EMG signal introduces a voltage offset, not already present in the action potential voltages, that centers the EMG signal about a non-zero voltage. The rectification circuit is connected to the difference circuit and is configured to rectify the EMG signal about the non-zero voltage to create a rectified EMG signal. The offset removal circuit is configured to remove the voltage offset from the rectified EMG signal to create an adjusted EMG signal. The integration circuit is connected to the offset removal circuit and is configured to integrate the adjusted EMG signal to produce a first EMG output signal for a client device.