EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: w3amd on February 24, 2016, 03:30:55 pm
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Hi all,
Is it possible to use this to measure impendence of a circuit? I want to measure a cabinet chassis in particular and look at the impedance for a few frequencies.
The test:
1) Use tracking generator output between two different points on the cabinet.
2) Use spectrum analyzer to measure the difference across these two points.
In the worst case the tracking generator output might be near short at some frequencies. Can it handle this? Or should I put a 50 ohm resistor in series with the tracking generator output?
Is there a better way?
TIA,
John
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You want to drive the DUT with the TG and sample it from the same point? Treating the DUT like a shunt (higher response means higher impedance, less loading)?
I guess it could work.
I'd put a 10dB attenuator on the TG output ( and maybe another one on the SA input ), and then do a normalization without the DUT. Then work out the math for how to interpret the resopnse as impedance.
>>Is there a better way?
I'd use a Directional Coupler ( Return Loss Bridge ) like the Mini-Circuits ZFDC-20-5.
See Alan's video: https://www.youtube.com/watch?v=iBK9ZIx9YaY (https://www.youtube.com/watch?v=iBK9ZIx9YaY)
Or this one from James Edgerton: https://www.youtube.com/watch?v=5W_abYvvVls (https://www.youtube.com/watch?v=5W_abYvvVls)