Excerpt from electronic documentation:
The Graph report displays any combination of system parameters versus input power, frequency or system temperature. This report is especially useful when a project contains one or more AGC loops. When AGC loops are present most system parameters vary with input power because the loop(s) adjusts its gain in an attempt to keep the power at the detector(s) constant. The graph below shows how the system gain and noise figure changes with input power because of the AGC loop.
