Reference Signal Subtraction for Low-Uncertainty Measurements
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Solution Overview
Problem
Existing measurement systems face challenges in effectively removing noise generated by sources other than the device under test, which leads to measurement uncertainties and inaccurate assessments of device performance.
Innovation Solution
A signal processing method that involves receiving an analog measurement signal from a device under test, digitizing it, and removing noise using a first noise reduction unit. Additionally, an analog reference signal is digitized and noise is removed using a second noise reduction unit, and a digital difference signal is determined by subtracting the noise-corrected reference signal from the noise-corrected measurement signal, effectively canceling out noise from sources other than the device under test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise reduction techniques are applied to remove noise from measurement signals, then measurement precision is improved, but device complexity increases due to multiple measurement units and noise reduction units
Solution Approach 1:
The measurement system is divided into separate functional units: a first measurement unit for acquiring measurement signals, a second measurement unit for acquiring reference signals, and separate noise reduction units for each signal type. This segmentation allows independent optimization of each unit while achieving comprehensive noise reduction through coordinated operation.
Solution Approach 2:
A reference signal is introduced as an intermediary element that carries the same noise characteristics as the measurement signal but without the device-under-test-specific information. By comparing the measurement signal with this intermediary reference signal through subtraction, the common noise components are eliminated, isolating the desired measurement information.
2Reliability
If multiple measurement units and noise reduction units are used, then noise cancelation is improved, but loss of time increases due to multiple signal processing steps
Solution Approach 1:
The reference signal is acquired and processed in advance to extract noise characteristics before the actual measurement signal analysis. The noise reduction units are pre-configured with the reference signal's noise profile, enabling faster real-time noise cancellation during measurement without requiring complex post-processing.
Solution Approach 2:
The system continuously acquires both measurement signals and reference signals simultaneously through parallel measurement units, maintaining an ongoing noise profile update. This continuous operation ensures that the noise cancellation remains adaptive and effective throughout the measurement process without interruption or repeated calibration.
Data Source
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AI summary
A signal processing method for reducing measurement uncertainties is described. The signal processing method comprises the steps of: - receiving, by means of a first measurement unit (20), an analog measurement signal from a device under test (14); - digitizing, by means of the first measurement unit (20), the analog measurement signal, thereby obtaining a digital measurement signal; - removing, by means of a first noise reduction unit (26), noise from the digital measurement signal, thereby obtaining a noise-corrected measurement signal; - receiving, by means of a second measurement unit (24), an analog reference signal, wherein the device under test (14) generates the analog measurement signal based on the analog reference signal; - digitizing, by means of the second measurement unit (24), the analog reference signal, thereby obtaining a digital reference signal; - removing, by means of a second noise reduction unit (28), noise from the digital reference signal, thereby obtaining a noise-corrected reference signal; and - determining, by means of a subtraction unit (34), a digital difference signal based on the noise-corrected measurement signal and based on the noise-corrected reference signal. Further, a measurement system (10) is described.