Maybe you mean "Equivalent Transfer Function Method" or "Describing Function Method" in control system theory.
Hello pancho_hideboo,
You are right - my answer was directed towards the HB method based on describing functions.
But - why are you so sensitive and touchy? My only intention was to answer a question concerning "the stability of a circuit which is in the nonlinear state?".
This was a very general question - and I have tried an answer, that`s all.
Regards
LvW
Just now, I have discovered that you have supplemented your former answer.
Your first answer was only: "I don`t think so" - without any explanation. This gave reason to a misunderstanding. (By the way: From the beginning I didn't realize that the question was asked in the RF part of the forum).