Karl-Arne's comments are very valid about receiver in band linearity. Designing
an AGC stage that gives good linearity as the gain is reduced is not as easy as
might be thought. Been there, done that...
Similarly, about producing clean signals for IMD testing. Wrote an Application
note some 25 years ago - had 'professional' customers who had problems...
As far as the 'IMD against tone' and 'IMD against PEP' is concerned, as long as
you state which one you're using, it doesn't matter. ITU recommendations use
PEP, because that's more valid when you are doing spectrum sharing studies. As
it is, of course, for in band IMD measurements.
As far as using a receiver S meter is concerned - the S stands for
'suspicious'. Rich said 'sucky' but it comes to the same thing!
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