Also there can toggle between units using "Amplitude" long press. So if user enter 0dBm and it display 0dBm then long push Amplitude and next it display 632.6mVpp and next 223.6mVrms. (note: it display it without offset even if there is offset ./ )
But about level flatness. SDG6022X is specified for ± 0.3dBm
Here sweeps using 7.50, 6.00, 3.00 and 0.00 dBm output level setting. Sweep range 2MHz - 200MHz.
Level absolute accuracy is not quaranteed here but it give quite good imagine about flatness. Also there is (quite good quality) 70cm BNC - N cable what attenuation is not corrected. With some experience it can assume flatness is least inside ± 0.15 dBm if use calibrated level meter and measure directly from SDG output port (even power total include all spurs and harmonics).
Flatness is not in "State of Art" class, not even "High End" class but it very good.
@oz2cpu some previous message is used just level as example 1v
Example SDG6kX can handle 200MHz 1.5Vpp or 0.530Vrms @50ohm
It is good to use right values for tell level and in some cases including impedance if talk example SDG displayed level. Vpp, Vp, Vrms or dBm etc just for avoid any misinterpretation.
And when talk SDG displayed levels also load impedance setup is important if not fully self-evident, it is not same if it is set for 50, 61 or 77 or 93, or 128 ohm or what ever user have set (setup range is free between 50ohm - 100kohm or Hi-Z.
SDG6022X just as factory new out from box. Output 50ohm, set for 50ohm load, 50ohm chinese high quality coax 70cm, and 50ohm input and all these have some ± tolerances.