Variable-Gain Differentiator Circuit for Noise-Resistant Derivative Estimation

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Solution Overview

Problem

Existing differentiator systems are highly sensitive to additive noise in input signals, which affects their accuracy in estimating signal derivatives.

Innovation Solution

A variable-gain differentiator circuit is designed using a series of non-inverting operational amplifiers and comparators, with a DC voltage-controlled variable-gain amplifier to adjust the gain and reduce noise sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional differentiator circuits are used, then signal differentiation can be performed, but the sensitivity to additive noise is high

Engineering Contradiction:

Improvedifferentiation accuracyVSAvoidnoise sensitivity

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements a variable gain differentiator where the gain parameter can be dynamically adjusted based on noise conditions. The circuit transitions from a fixed-gain differentiator to a dynamically adaptable system that can modify its amplification factor to optimize the balance between differentiation accuracy and noise suppression.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the gain parameter of the differentiator circuit from a fixed value to a variable parameter. By adjusting the gain parameter, the system can adapt to different noise levels and signal conditions, thereby reducing noise sensitivity while maintaining differentiation precision.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the gain of the differentiator is increased to improve differentiation precision, then measurement accuracy improves, but noise sensitivity increases

Engineering Contradiction:

Improvederivative estimation accuracyVSAvoidamplified noise

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent creates a dynamic gain control mechanism that adjusts the amplification factor in real-time. Instead of using a fixed high gain that always amplifies noise, the system dynamically modulates the gain parameter to achieve optimal differentiation precision while suppressing noise amplification through adaptive parameter adjustment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention incorporates feedback mechanisms that monitor the output signal quality and adjust the gain parameter accordingly. This feedback loop enables the system to automatically reduce gain when noise becomes dominant and increase gain when signal precision is the limiting factor, thereby resolving the trade-off between precision and noise amplification.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250096760A1Variable gain differentiator for analog signal differentiation

Publication Date: 2025.03.20 KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS

AI summary

Systems and methods for a variable-gain differentiator in series with at least two non-inverting amplifiers. The variable-gain differentiator is connected to a voltage-controlled source at its non-inverting input and to its output at its inverting input. The output is connected to the non-inverting input of the first non-inverting amplifier. The output of the first non-inverting amplifier is connected to the input of the second non-inverting amplifier. The output of the second non-inverting amplifier is connected to a series of three integrators. Each integrator is connected to its output by a feedback path.