Analog Signal Isolation via Microwave Coupling for Floating Measurements
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Solution Overview
Problem
Test and measurement systems face challenges in accurately measuring floating signals relative to each other without referencing ground, as direct connections can lead to erroneous data and exceed oscilloscope design constraints.
Innovation Solution
The implementation of an isolation barrier using a microwave structure that electromagnetically couples floating analog signals to a ground referenced test and measurement system, while preventing sub-microwave signals from crossing the isolation barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct connection is made between the DUT and the oscilloscope, then the measurement system can reference ground, but the measurement precision deteriorates due to erroneous data and improper scaling when measuring floating signals
Solution Approach 1:
The patent introduces an isolation barrier as an intermediary component between the DUT and the oscilloscope. This barrier includes a transformer that magnetically couples the floating signal from the DUT to the ground-referenced oscilloscope without direct electrical connection. The transformer acts as a mediator that transfers the signal while maintaining galvanic isolation, thereby preventing ground reference errors and improving measurement reliability without sacrificing signal fidelity
Solution Approach 2:
The patent replaces direct electrical connection (mechanical/electrical contact) with electromagnetic coupling through a transformer. Instead of using a direct wire connection that references ground, the system uses magnetic field coupling to transfer the signal across the isolation barrier. This substitution eliminates the harmful ground reference connection while maintaining signal transmission, resolving the contradiction between measurement precision and data accuracy
2Reliability
If an isolation barrier is introduced to prevent direct connection, then data accuracy improves, but the device complexity increases due to additional isolation components
Solution Approach 1:
The isolation barrier is designed to perform multiple functions simultaneously: it provides galvanic isolation to prevent ground reference errors, transfers the floating signal from the DUT to the oscilloscope, and maintains impedance matching for accurate measurements. By consolidating these functions into a single integrated component, the system achieves high data accuracy without proportionally increasing complexity
Solution Approach 2:
The patent transforms the signal from a floating voltage reference to a magnetically coupled signal with different electrical characteristics. The transformer changes the signal's reference frame from floating to ground-referenced while maintaining the original signal integrity. This parameter transformation allows the use of standard ground-referenced oscilloscopes to measure floating signals, improving reliability without requiring complex custom measurement systems
3Ease of operation
If the oscilloscope measures voltage relative to ground, then the measurement system operates within design constraints, but the measurement precision deteriorates when measuring differential voltages due to large base voltage values
Solution Approach 1:
The patent segments the measurement system into two independent parts: the floating DUT side and the ground-referenced oscilloscope side, separated by the isolation barrier. The transformer on the oscilloscope side measures only the differential voltage component that crosses the isolation barrier, excluding the large common-mode base voltage. This segmentation allows the oscilloscope to operate within its ground-referenced design constraints while accurately measuring small differential signals without being overwhelmed by large voltage offsets
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 solution allows for accurate measurement of floating signals relative to each other without grounding issues, ensuring precise data and compliance with oscilloscope design constraints.
Implementation Method 1
a microwave structure to transmit the microwave frequency analog signal across the isolation barrier via electromagnetic coupling
Data Source
AI summary
Disclosed is a signal isolating test instrument, such as an electronics test probe. The instrument includes an input to receive a floating analog signal. An upconverter is employed to modulate the floating analog signal to a microwave frequency analog signal. An isolation barrier prevents coupling of the floating analog signal to an earth ground. The instrument employs a microwave structure to transmit the microwave frequency analog signal across the isolation barrier via electromagnetic coupling. A downconverter is then employed to demodulate the microwave frequency analog signal to obtain a ground referenced test signal corresponding to the floating analog signal.