TDR

Cursitor Doom · 2026-07-24T17:07:11+00:00

Gentlemen,Does anyone here have a dedicated TDR? I'd previously assumed theywere only good for 'distance to fault' applications, but was disabusedof my ignorance during a recent read of Tom Lee's Planar MicrowaveEngineering, in which it was stated that they can also be used foridentifying the value of caps and inductors by means of the shape ofthe reflection and doing a bit of integration to it.A TDR is one of the vanishingly few items of test gear I do notpossess. I have a 50ps pulse generator which can be used with a fast'scope to achieve a certain amount of functionality, but I waswondering how much more useful and versatile a stand-alone TDR mightbe.I use a VNA for determining the value of small caps and coils and findit hard to believe any TDR could give better results than that.However, once again I could be wrong. Info, anyone?

Jul 24, 2026 Last reply: 1 month ago 21 Replies

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Glen Walpert 1 month ago

If you don't have the option installed, it looks like you can install it for free:

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Cursitor Doom 1 month ago

Thanks. I know there are some codes you can input to unlock the range and take it from 3Ghz up to 6. However, the matching S parameter test set still tops out at 3 and there's no way to expand it.

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