I am following "Load-Pull Measurements Using SpectreRF" in "PA Design Using SpectreRF". There is a problem I can't figure out. After run PSS analysis, I choose Results—Direct Plot—Main Form; Click pss analysis and choose the Power Contours function to plot Power Contours. However, after click Power Contours, there is no "plot" button and at the bottom of the Direct Plot Form displays this:
"A two dimensional parametric sweep must be performed before the above selected function can be executed."
I guess this is my problem.
Could you explain it? What is the two dimensional sweep that I need to run?