Phase-Sensitive Signal Normalization for Interference-Robust Measurement
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Solution Overview
Problem
Existing measuring devices for non-electrical quantities face challenges in minimizing the influence of interference signal components on measured values, particularly in systems like gas analyzers, where changes in magnetic circuit properties affect the measurement results, requiring costly equipment for current measurement.
Innovation Solution
Incorporating a normalization stage that normalizes the measured value using the square of the interference signal value, eliminating the need for current measurement equipment and compensating for interference effects by processing both useful and interference signal components through the same analog and digital pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurement equipment is added to compensate for interference, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent converts the harmful interference signal component into a useful normalization factor. By measuring the interference signal value and using its square to normalize the measured value, the system transforms the previously harmful interference into a beneficial reference for compensation, eliminating the need for separate current measurement equipment.
Solution Approach 2:
The interference signal measurement serves multiple functions: it acts as both a diagnostic indicator for system health monitoring and as a normalization reference for measurement compensation. This multi-functionality eliminates the need for dedicated current measurement equipment while maintaining measurement precision.
2Measurement precision
If current measurement equipment is added to compensate for interference, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent converts the harmful interference signal component into a useful normalization factor. By measuring the interference signal value and using its square to normalize the measured value, the system transforms the previously harmful interference into a beneficial reference for compensation, eliminating the need for separate current measurement equipment.
Solution Approach 2:
The system uses its own interference signal measurement to perform the normalization function that would otherwise require external current measurement equipment. The measuring device serves itself by utilizing the interference signal it already detects for diagnostic purposes to also perform measurement compensation.
3Measurement precision
If interference signal components are attenuated by filter measures, then measurement precision is improved, but loss of information occurs
Solution Approach 1:
Instead of filtering out the interference signal component, the patent converts it into a useful normalization reference. The interference signal value is squared and used to normalize the measured value, transforming the harmful interference into a beneficial compensation factor that preserves all signal information.
Solution Approach 2:
Rather than removing the interference signal through filtering, the patent inverts the approach by utilizing the interference signal for normalization. This inversion preserves the complete signal information while achieving measurement compensation through a fundamentally different methodology.
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 allows for accurate normalization of measured values without requiring current measurement equipment, effectively compensating for interference and changes in the signal path, thereby enhancing measurement reliability and reducing operational costs.
Implementation Method 1
the electrical measurement signal having a useful signal component dependent on the non-electrical variable with twice the frequency and an interference signal component dependent on the alternating current with the frequency
Implementation Method 2
the signal processing software being designed to make the digital signal phase-sensitive by multiplying it with a reference signal at twice the frequency to be detected and processed by subsequent low-pass filtering
Data Source
Figure 1~3
Figure 4~5
AI summary
In a measuring device, a non-electrical variable (2) is converted into an electrical measurement signal (3) by means of an alternating electrical current of frequency (f), which has a useful signal component (3(2f)) that is dependent on the non-electrical variable (2) and has twice the frequency ( 2f) and an interference signal component (3 (f)) which is dependent on the alternating current (I (f)) and has the frequency (f). A digital signal (9) is generated from the measurement signal (3) by pre-processing and digitization, which is detected phase-sensitively by multiplication (13) with a reference signal (14) at twice the frequency (2f) and by subsequent low-pass filtering (15) to one of the non-electrical variable (2) proportional measured value (11) is processed. The digital signal (9) is also detected phase-sensitively by multiplication (18) with a further reference signal (19) at the simple frequency (f) and processed by subsequent low-pass filtering (15) to form an interference signal value (20). According to the invention, the interference signal value (20) is used to normalize the measured value (11) by normalizing it in a normalization stage (22) by forming the quotient with the square of the interference signal value (20) and outputting it as a normalized measured value (11).