Dual-Path Signal Measurement for External Noise Cancellation
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Solution Overview
Problem
Existing measurement systems struggle to effectively cancel noise generated by sources other than the device under test, leading to measurement uncertainties and inaccuracies in high-precision assessments.
Innovation Solution
A signal processing method involving digitization and noise reduction of both measurement and reference signals, followed by signal level adaptation and subtraction to cancel noise from external sources, resulting in a digital difference signal containing only device-specific noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement systems are used to measure device under test, then measurement can be performed, but noise from external sources (signal generator, measurement instrument) degrades measurement precision
Solution Approach 1:
The measurement system is segmented into two independent signal paths: one for the measurement signal (through the device under test) and one for the reference signal (bypassing the device under test). Each path has its own measurement circuit that independently captures noise from external sources. This segmentation allows separate noise characterization and subsequent cancellation through subtraction, effectively removing external noise contributions from the final measurement.
Solution Approach 2:
A reference signal path acts as an intermediary that captures noise from external sources (signal generator, measurement instrument) without passing through the device under test. This reference path serves as a mediator that allows the system to identify and subtract external noise components from the measurement signal, thereby improving measurement precision by isolating the device under test's actual performance characteristics.
2Measurement precision
If noise cancellation techniques are applied to remove noise from measurement signal, then measurement precision improves, but measurement system complexity increases
Solution Approach 1:
The system merges the measurement signal path and reference signal path at the subtraction stage, where the reference signal (containing external noise) is subtracted from the measurement signal. This merging approach allows noise cancellation to be achieved through a single subtraction operation rather than requiring complex filtering or processing, thereby improving measurement precision while keeping the system relatively simple.
Solution Approach 2:
The system changes the parameter of signal representation by capturing both measurement and reference signals in the same time domain and using digital subtraction. This parameter change from analog filtering to digital signal processing allows for precise noise cancellation while maintaining system simplicity, as the subtraction can be performed with high precision using standard digital processing techniques.
Data Source
AI summary
A signal processing method includes the steps of: receiving, by a first measurement circuit, an analog measurement signal from a device under test; digitizing, by the first measurement circuit, the analog measurement signal, thereby obtaining a digital measurement signal; removing, by a first noise reduction circuit, noise from the digital measurement signal, thereby obtaining a noise-corrected measurement signal; receiving, by a second measurement circuit, an analog reference signal, wherein the device under test generates the analog measurement signal based on the analog reference signal; digitizing, by the second measurement circuit, the analog reference signal, thereby obtaining a digital reference signal; removing, by a second noise reduction circuit, noise from the digital reference signal, thereby obtaining a noise-corrected reference signal; and determining, by a subtraction circuit, a digital difference signal based on the noise-corrected measurement signal and based on the noise-corrected reference signal. Further, a measurement system is described.