Understanding Output Changes with Sensitivity on SR830 Lock-In Amplifier

[Andres kubliki]

Does somebody knows why the output changes with the change of the sensitivity?

When I'm measuring noise, let say I have a value of 5nV/sqrt(Hz) at 10 nV sensitivity. When I switch to 20 nV, the output goes to 10nV/sqrt(Hz). Why?
Which on is them the correct?

 

[Charles Link]

Just a guess might be that some of the noise signals are saturating the amplifier at 10nV sensitivity and don't get measured in their entirety at this level of sensitivity, but that is only a guess.