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Ansys Learning Forum › Forums › Discuss Simulation › Electronics › ANSYS Electronics Circuit:Transient analysis error › Reply To: ANSYS Electronics Circuit:Transient analysis error

January 26, 2024 at 2:59 pm
Dan Dvorscak
Ansys Employee

The s-parameter rejection is due to the state-space (the method by which we solve s-parameters in the time domain) fitting error is greater than 10%. That is a very strong indicator that the model is behaving in a non-physical manner. I would recommend running the causality checker in the Network Data Explorer to see if if flaggs the model as non-causal. 

Though you had mentioned this being based on an LNA simulation. Undersampeld frequency domain data can often appear as numerically non-causal. On a related note, the no DC point warning is coming from the same s-parameter model. What was the frequency sweep settings for the LNA that crated this?Â