Auto-Phase Compensation Circuit for Power Frequency Common Mode Interference Suppression
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Solution Overview
Problem
Existing bioelectrical signal measurement systems face challenges in effectively suppressing power frequency common mode interference due to incomplete phase opposition of feedback signals and uncertain system transfer functions, leading to reduced interference suppression capabilities.
Innovation Solution
An embedded system circuit is introduced that performs auto-phase compensation, analyzing bioelectrical signals to determine the necessary phase compensation for the amplified signal, ensuring it is in opposite phase with the power frequency common mode interference, and selectively outputs this phase-compensated signal to improve interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback capacitance is added to ensure system stability, then system stability is improved, but the phase opposition between feedback signal and common mode signal becomes incomplete, reducing interference suppression capability
Solution Approach 1:
The patent dynamically adjusts the feedback capacitance value based on the detected phase difference between the feedback signal and the common mode interference signal. By changing the capacitance parameter in real-time, the system achieves both stability and complete phase opposition, resolving the contradiction between stability and interference suppression.
Solution Approach 2:
The patent implements a feedback mechanism that continuously monitors the phase relationship between the feedback signal and the common mode signal. This feedback information is used to adjust the feedback capacitance, creating a closed-loop control system that simultaneously maintains stability and achieves optimal interference suppression.
2Stability of the object's composition
If corner frequency is lowered to ensure system stability, then system stability is improved, but the phase shift of the system changes, preventing complete phase opposition with common mode signal
Solution Approach 1:
The patent makes the corner frequency dynamic rather than fixed. The corner frequency is adjusted in real-time based on the detected phase difference, allowing the system to adapt to different operating conditions and maintain both stability and complete phase opposition for optimal interference suppression.
Solution Approach 2:
The patent dynamically changes the corner frequency parameter based on feedback from the phase detection circuit. By adjusting this critical parameter, the system achieves both stability and complete phase opposition between the feedback signal and common mode interference.
3Device complexity
If fixed hardware circuit frequency characteristic is used, then circuit simplicity is maintained, but the uncertain system transfer function prevents complete phase opposition, reducing interference suppression capability
Solution Approach 1:
The patent introduces a feedback mechanism that detects the actual phase relationship between signals and uses this information to adjust the driving circuit parameters. This feedback approach allows the simple hardware circuit to adapt to uncertain system transfer functions and achieve complete phase opposition.
Solution Approach 2:
The system performs self-adjustment by automatically detecting the phase difference and modifying its own parameters accordingly. This self-service capability allows the fixed hardware circuit to compensate for uncertainties in the system transfer function without external intervention.
Data Source
AI summary
A method for suppressing power frequency common mode interference comprises the following steps of: receiving a bioelectrical signal from a living body on examination by phase compensating and processing circuitry; analyzing the characteristics of the bioelectrical signal and determining a phase compensation amount by the phase compensating and processing circuitry; performing a corresponding time delay processing on an amplified signal outputted by the driving circuit; and providing the delay signal to the living body on examination.