Differential Signal Processing for Temperature-Drift Compensation

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Solution Overview

Problem

In signal processing systems, temperature variations and noise, particularly clock noise, lead to errors in estimating input signals from output signals, especially when calibration is done at different temperatures, compromising precision.

Innovation Solution

A differential signal processing method using two systems to receive input signal y and its opposite, generating weighted difference and sum signals to compensate for temperature effects and reduce noise, allowing for accurate estimation of y and temperature determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single system processes the input signal, then the device complexity is low, but measurement precision deteriorates due to temperature variations and noise

Engineering Contradiction:
Improveprecision of input signal estimationVSAvoidcomplexity of processing system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The single processing system is segmented into two differential systems (S1 and S2) that process the input signal and its opposite separately. This segmentation enables the system to distinguish between signal components and noise/temperature drift components, thereby improving measurement precision through differential measurement techniques.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A second system S2 is created as a copy of the first system S1, but configured to process the opposite of the input signal (-y). This copying approach allows for differential processing where the output signals can be combined to eliminate common-mode errors such as temperature drift and clock noise, improving measurement precision.

Inventive Principle:
Principle #26Copying

2Measurement precision

If calibration parameters are used without temperature compensation, then the ease of operation is high, but measurement precision deteriorates due to temperature drift

Engineering Contradiction:
Improveprecision of signal estimationVSAvoidsimplicity of processing operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system uses feedback by processing both the input signal y and its opposite -y through identical systems, then combining the outputs to eliminate temperature-dependent parameters. The feedback mechanism allows the system to automatically compensate for temperature drift without requiring manual recalibration, thereby improving measurement precision while maintaining ease of operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the parameter being measured by processing both y and -y simultaneously. This parameter transformation allows temperature-dependent parameters (X0 and coefficients of f) to be eliminated through mathematical operations on the combined outputs, improving measurement precision without requiring temperature compensation calibration.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If digital processing with sampling is used, then the productivity is high, but measurement precision deteriorates due to clock noise

Engineering Contradiction:
Improveprecision of output signalVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system converts the harmful clock noise into a beneficial differential signal. By processing both y and -y with the same sampling clock, the clock noise appears as a common-mode signal that can be eliminated through differential combination of the outputs. This allows high-speed digital processing to be maintained while improving measurement precision by converting the harmful clock noise into a removable artifact.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS7908122B2Signal processing device for systems in differential configuration
Publication Date: 2011.03.15 THALES SA
  • US7908122B2 patent drawing

AI summary

A signal measurement and processing device includes two systems allowing a signal and its opposite to be simultaneously received at the input and two signals able to take polynomial form, as a function of the input signals, to be returned. The device includes means for performing a weighted sum and difference of the two output signals in such a manner that at least the weighted sum is independent to a first order of the variations in the input signals. This processing operation is particularly well adapted to systems subjected to spurious effects such as thermal drifts.