Is FRA sweep in Qspice possible?


I wonder if it’s possible to do a FRA sweep in Qspice?
If so how?

I tried to do like this:

Unfortunately it didn’t work for me, I assume it may be a syntax? due to "Error: no such function ‘‘mod’’ "

FRA is a native analysis in QSPICE. There’s an example: Files=>Open Demo=>BodePlot.qsch

But I can implement mod(,), too.


Any examples for using .bode for amplifiers available?
Like inverted/non-inverted OpAmp, FDA, etc…

– Victor

I didn’t prepare any .bode examples for circuits that are well evaluated in continuous time. I’d just do those in a .ac. But, yes, you can use .bode for such circuits, too.


Hi Mike,

I’ve tried the native .bode, however I seem to get quite different results compared to LTspice
and between excitation on voltage source vs Resistors in Qspice. ( se snapshots below)

I’ve also tried again to do the same measurements in Qspice as in LTspice, as it seems as .mod have been added? but I’m unable to plot the measurments, due to access restrictions maybe it’s a corporate thing, I’ll try it on my home PC later aswell.

It seems like excitation of R3 equals putting a voltage source in parallell with excitation.

Changed orientation of R3 with 180 degrees, seems to invert the results

rotating 180 degrees does not affect the result for V5