Analog signal isolator
AssigneeTektronix, Inc.
InventorsJonathan S. Dandy, Daniel G. Knierim
Life of this patent
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Abstract
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.
Claims20
An apparatus comprising:
- an input to receive a floating analog signal;
- an upconverter, coupled to the input, the upconverter to modulate the floating analog signal to a microwave frequency analog signal;
- an isolation barrier to prevent coupling of the floating analog signal to an earth ground;
- and
- a microwave structure to transmit the microwave frequency analog signal across the isolation barrier via electromagnetic coupling,
- wherein the microwave structure includes an input conductor on an input side of the isolation barrier and an output conductor on an output side of the isolation barrier, the input side opposite the output side, the input conductor and the output conductor electromagnetically coupled across the isolation barrier, and
- wherein the microwave structure is tuned to allow the microwave frequency analog signal from the upconverter to traverse the isolation barrier from the input conductor to the output conductor substantially unchanged while preventing sub-microwave signals from traversing the isolation barrier.
A method comprising:
- receiving a floating analog signal;
- modulating the floating analog signal into a microwave frequency analog signal;
- and
- using a microwave structure to transmit the microwave frequency analog signal across an isolation barrier in a test and measurement system,
- wherein the microwave structure includes an input conductor on an input side of the isolation barrier and an output conductor on an output side of the isolation barrier, the input side opposite the output side, the input conductor and the output conductor electromagnetically coupled across the isolation barrier, and
- wherein the microwave structure is tuned to allow the microwave frequency analog signal from the upconverter to traverse the isolation barrier from the input conductor to the output conductor substantially unchanged while preventing sub-microwave signals from traversing the isolation barrier.
A test network comprising:
- an isolated signal probe including
- an input for receiving a floating signal from a device under test,
- an output,
- a substrate including an input side, an output side, a proximate end, and a distal end,
- a pair of differential input traces extending from the proximate end of the input side of the substrate,
- a pair of differential output traces extending from the distal end of the output side of the substrate, and
- an isolation barrier of non-conductive material included in the substrate, the isolation barrier positioned between the differential input traces and the differential output traces for electro-magnetic coupling between the differential input traces and the differential output traces at micro-wave frequencies and isolation of the differential input traces from the differential output traces at sub-microwave frequencies,
- wherein the input is coupled to the pair of differential input traces, and the output is coupled to the pair of differential output traces;
- and
- a ground referenced test system including an input port for receiving a ground referenced test signal representing the floating signal from the output of the probe, wherein the input port of the test system is galvanically isolated from the device under test.
Dependencies are inferred from the claim text.