How to plot gain vs output diff voltage?

[jszair]

I'd like to test output swing, so how do I plot differential gain vs output differential voltage? I use balun to get output differential voltage.

Thanks!

 

[prcken]

i think just do DC, and take the derivative of the output.
BTW: why don't you measure the peak-to-peak swing instead of the gain? you can also plot the swing versus time.