How to Search for 1dB Compression Point with CXA Opt. ESC and EXG ?

Hi,

I have an N9000A CXA and would like to make amplifier measurements with an external Keysight EXG signal generator. There is an application named ESC for the CXA that allows you to draw gain curves, ... by automatically controlling the level of the EXG, thereby doing a power sweep. That works fine, but what is the trick to AUTOMATICALLY compute or search the 1dB compression point ?

Thanks

  Wolfgang