Step analysis on FRA analysis

Hello
I am testing to do a step analysis on a FRA analysis of a simple RC circuit. I want to use this later on a dc-dc converter. I am stepping two values of the capacitor 100nF and 10 nF.
The results of the text file seem ok. However, when doing the plotting it seems that Qspice only represents the results of one of the values of Cf.
Any idea?
Thanks very much!

RC-circuit-FRA-test-step-on-Cf.qsch (3.5 KB)

A quick verify, change the order of freq and Cf. In general, I put x-axis quantity in first sweep. What I don’t understand is why x-axis quantity in your original .step sequence is also freq instead of Cf.

.step dec param freq 100 100K 10 param Cf list 100n 10n

Thank you very much. That works.
You won’t believe but I also considered inverting the order of the parameters but I dismissed the idea because it seemed to me that it wouldn’t work either …
Thanks!

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Hi Marcos and Kelvin,

Just accidentally run the dicussed simulation and found I cannot get the curves you had. My result:

.
What can be wrong? I have tried both fast math or not fast math, with latest QSPICE version.

It appears that the issue started with the build from the 19-Oct. I have just submitted this case to Mike for review.

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It seems the solution can only be fixing Tstart when .meas is used. Attached is a modification that should work. The downside is that the data file (.qraw) will be larger as more data is saved.

RC-circuit-FRA-test-step-on-Cf (Fix Tstart).qsch (3.2 KB)

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Hi Kelvin,
Thanks for your always helpful support!

Best regards
Yi