I'm faced with the problem of explaining the harmonic production in a system where the second order intercept points of the cascaded components are unknown. As a way to bolster my explanation, I would like to provide some realistic sample calculations that might reasonably approximate what we observe the harmonic levels to be, but I don't have any IIP2 information except what I can get from the observations.
In other words, I would like to show that the observations agree (within some reasonable amount) with what we could expect from a cascade analysis based on the IIP2 and IIP3 values of the devices involved. (Or, alternatively, what we observe is inconsistent with what should be expected!)
I know from experience (IIRC) that for the devices we are using, a rule of thumb is that the IIP3 is generally about 15 to 16 dB above the 1 dB compression point.
However, I never needed such a rule of thumb for the IIP2 until now. Is there one? If someone can cite an authoritative reference in addition to providing the rule of thumb that would be even better. (I will have to be convincing with my analysis.)
The active devices involved are multi-octave class A RF amplifiers.
I understand how to do the cascade analysis and I am experienced in doing it for narrow bandwidth systems. The system at hand has a multi-octave bandwidth, so harmonic performance is an important issue. I am trying to characterize an individual stage. Generally, I know the 1 dB compression point and IIP3 for each stage.
(Could someone help with the tags on this questions?)