Analog Signal Test Using Reference Subtraction
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Solution Overview
Problem
Existing methods for testing analog signals require high-performance analog-to-digital converters to detect small distortions, which is costly and complex, especially when dealing with signals that have small distortion components compared to the ideal waveform, and often necessitate the use of expensive programmable notch filters for different frequencies.
Innovation Solution
Generating a reference signal based on known parameters of the signal under test, combining it with the signal to create a smaller amplitude combination signal that can be evaluated with relaxed ADC specifications, allowing for accurate detection of small distortions without needing high dynamic range converters or complex filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-performance analog-to-digital converters with big dynamic range are used to detect small distortions, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the dominant signal component from the total signal by generating a reference signal that matches the ideal waveform characteristics (amplitude, frequency, phase) and subtracting it from the signal under test. This separation isolates the small distortion components that need to be measured, allowing them to be detected without requiring the ADC to handle the full dynamic range of the original signal.
Solution Approach 2:
The patent changes the parameter range of the signal being measured by transforming the original signal with large amplitude into a combination signal with much smaller amplitude. By generating a reference signal with matching parameters and subtracting it, the resulting combination signal contains only the distortion components, effectively changing the amplitude parameter from the original signal level to the distortion level, which relaxes ADC dynamic range requirements.
2Device complexity
If notch filters are used to suppress the main signal component, then dynamic range requirements are relaxed, but measurement precision deteriorates due to non-ideal filter characteristics affecting distortion components
Solution Approach 1:
Instead of using physical filters to remove the main signal, the patent creates a precise digital or analog copy of the ideal signal waveform as a reference signal. This reference signal is generated based on known parameters (amplitude, frequency, phase) and subtracted from the signal under test, providing an ideal subtraction without the imperfections of physical notch filters.
Solution Approach 2:
The patent replaces the mechanical/analog notch filter system with a signal processing approach using reference signal generation and subtraction. This substitution eliminates the need for physical filters and their associated imperfections, achieving signal component separation through mathematical operations instead of analog filtering.
3Adaptability or versatility
If programmable notch filters are used for different signal frequencies, then adaptability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent implements adaptability through dynamic parameter adjustment of the reference signal generator. The reference signal's amplitude, frequency, and phase parameters can be programmatically adjusted to match the signal under test characteristics, allowing the system to adapt to different test frequencies without requiring programmable filters. This dynamic parameter control provides flexibility while maintaining system simplicity.
Data Source
AI summary
A method and a corresponding system for testing an analog signal under test includes using knowledge of at least one parameter of the signal under test. The method includes generating a reference signal using the knowledge of at least one parameter of the signal under test, combining the generated reference signal with the signal under test, resulting in a combination signal, and evaluating the combination signal for testing the signal under test.