Thank you all for the replies. Now I understand better. I do not have full license nonlinear simulator, but I downloaded the student version of Ansoft Designer. I don't know if it includes the nonlinear simulator. Anyway, I think I will start by trying the load-pull technique. I have not done that before, but I have read it from books years ago. It's time to go back to the book again. Will the result from load-pull testing give me information to match the input?