Freq as a param in AC analysis

Is there a way to use Freq as a param in AC analysis simulation?
I know that “Freq” can be used in a plot statement but when I tried to use it in Behavioral source I got an error.

@RM_Simulate ,

You can use frequency as a part of a Voltage source using the SINE() function.

Is that what you are looking for?


Not exactly.
For example, I can use Freq in a plot statement like following.
.plot (V(1)/I(1))/(2piFreq)
However, I can’t use “Freq” in a B source. I get a message of “Unresolved parameter: “FREQ””

It can be a bit tricky when you need to include frequency in an “.ac” simulation.

I have just updated my Command Reference Guide for this discussion. You can download the updated guide and search for the topic “.ac”. I suggest considering the idea of using .step param frq… with .ac list frq. This approach may help you achieve what you need.

Qspice/Guideline at main · KSKelvin-Github/Qspice

Thanks for your reply.
I am not sure if I am looking at the updated file, but I couldn’t find what you mentioned in the document.

OH!!! My bad, I mistakenly load to root directory, and just reload the file. Please review again.

Qspice - Command Reference Guide by KSKelvin.pdf


Thanks so much, Kelvin