Microwave Analog Isolator for Floating Signal Measurement
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Solution Overview
Problem
Test and measurement systems face challenges in isolating floating signals from ground-referenced signals, leading to erroneous data and improper scaling due to direct connections, which can result in injury or equipment damage.
Innovation Solution
An electromagnetically coupled mechanism using an upconverter to modulate floating analog signals to a microwave frequency band, transmitted across an isolation barrier via a microwave structure, and then demodulated to obtain a ground-referenced test signal, preventing direct current path to ground and allowing only desired frequency signals to cross the barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a direct connection is made between the DUT and the oscilloscope, then the measurement system can operate with ground reference, but the floating signals become incorrectly referenced to ground causing erroneous data and improper scaling
Solution Approach 1:
An isolation barrier is introduced 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 input, allowing signal transfer while preventing direct galvanic connection. The transformer acts as a mediator that translates the floating signal into a ground-referenced signal without creating a direct electrical path, thus resolving the reference conflict.
2Measurement precision
If an isolation barrier is introduced to prevent direct connection, then signal reference accuracy is improved, but the device complexity increases due to additional isolation components
Solution Approach 1:
The patent replaces complex electronic isolation circuits with a transformer-based magnetic coupling system. Instead of using complicated active isolation components or multiple circuit stages, the solution employs a passive transformer that provides galvanic isolation through magnetic field coupling. This substitution simplifies the isolation system while maintaining signal reference accuracy, as the transformer naturally blocks DC paths and provides clean galvanic isolation.
3Measurement precision
If the oscilloscope measures voltage relative to ground, then ground-referenced signals are measured correctly, but floating signals show large base voltage values that obfuscate fine differential measurements
Solution Approach 1:
The measurement system is segmented into two distinct domains: a floating domain for the DUT signals and a ground-referenced domain for the oscilloscope. The transformer creates a clear separation between these domains, allowing the floating differential signals to be measured accurately in their own reference frame while being transferred to the ground-referenced oscilloscope for display. This segmentation prevents the large common-mode voltage from contaminating the differential measurement.
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 effectively isolates floating signals from ground-referenced test systems, preventing grounding and ensuring accurate measurements while allowing microwave frequency signals to be transmitted, thus preventing damage and ensuring safety.
Implementation Method 1
a microwave structure to transmit the microwave frequency analog signal across the isolation barrier via electromagnetic coupling
Data Source
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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 in the instrument 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.