Electric Potential Sensor Coherent Feedback Signal
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Solution Overview
Problem
Existing electric potential sensors face challenges in accurately measuring weak capacitive coupling signals, particularly in medical and microscopic applications, due to noise issues and poor signal-to-noise ratios, which hinder precise signal capture and stability.
Innovation Solution
The implementation of a coherent narrowband feedback signal in electric potential sensors enhances the signal-to-noise ratio by applying a feedback signal that is tuned to specific frequencies, thereby increasing sensitivity and rejecting other frequencies, and incorporates techniques like bootstrapping, guarding, and neutralization to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high input impedance electrometer is used to measure small electrical potentials, then sensitivity is improved, but stability deteriorates
Solution Approach 1:
The patent employs multiple feedback mechanisms including guard feedback, bootstrap feedback, and neutralisation feedback. These feedback circuits continuously monitor and adjust the sensor operation to maintain stability while preserving high input impedance, thereby resolving the contradiction between sensitivity and stability
Solution Approach 2:
The patent dynamically adjusts circuit parameters such as feedback impedance values and capacitor configurations to optimize the balance between sensitivity and stability under different operating conditions, allowing the system to maintain high measurement precision while ensuring operational stability
2Measurement precision
If ancillary circuits providing feedback are added to increase sensitivity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated circuit blocks. For example, the guard amplifier, bootstrap capacitor, and neutralisation circuit are merged into a coordinated feedback system that achieves multiple objectives simultaneously, reducing the overall complexity compared to separate independent circuits
Solution Approach 2:
The feedback circuits are designed to serve multiple purposes: the same feedback network provides both sensitivity enhancement and stability maintenance, and the ancillary circuits simultaneously perform guarding, bootstrapping, and neutralisation functions, thereby improving measurement precision without proportionally increasing complexity
3Adaptability or versatility
If broadband feedback signal is used, then feedback coverage is improved, but signal to noise ratio deteriorates
Solution Approach 1:
The patent applies different feedback strategies for different frequency ranges. Narrowband feedback is used at specific critical frequencies where signal enhancement is most needed, while broadband feedback provides general stability. This localized approach ensures high signal-to-noise ratio at measurement frequencies without sacrificing overall feedback coverage
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
This approach significantly enhances the signal-to-noise ratio, allowing for more accurate signal measurement and improved stability in sensors, even in situations with weak capacitive coupling, by selectively amplifying the measurement signal and reducing noise interference.
Implementation Method 1
at least one detection electrode arranged for capacitive coupling with a sample under test and for generating a measurement signal
Implementation Method 2
feedback means for applying a coherent feedback signal to the input of the sensor amplifier for enhancing the signal to noise ratio of the sensor
Data Source
AI summary
The invention provides an electric potential sensor including, at least one detection electrode arranged for capacitive coupling with a sample under test and for generating a measurement signal, and a sensor amplifier adapted to receive the measurement signal as input and to supply an amplified detection signal as output. An input impedance enhancing element provides a high input impedance to the sensor amplifier for increasing the sensitivity of the electrode to reduced electric potentials, and a feedback element applies a coherent feedback signal to the input of the sensor amplifier for enhancing the signal to noise ratio of the sensor.