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On Sun, Feb 9, 2025 at 01:23 AM, DiSlord wrote:

Here is renormalization in coppermountaintech
Analysis > Fixture Simulator > Port Z Conversion
(z)-c.html

Unfortunately the link you provided was cutoff and did not work. Hopefully groups.io formats this one correctly...

(z)-c.html

Copper mountain Provides for several Fixture Simulations. Here is the link to the topic.


The current Port Z function in the NanoVNA changes the reference impedance using only the real part with imaginary set to zero.. The measurement is still made using 50 ohms on Port 1 (CH0) and Port 2 (CH1) and a mathematical conversion of the matrix of S-parameters measured at 50 ohms to the matrix of S-parameters with a reference impedance entered by the user is generated. In my opinion there is a limitation to this method in that the DUT is being driven and loaded by 50 ohms and that only linear passive devices will yield correct results. Non linear devices or active circuits will not be tested with the impedance they are designed to operate with and simulation using this method will not yield correct results. So a 300 ohm resistive attenuator would measure OK but a crystal filter circuit that was not designed to work in a 50 ohm system would not.

Roger