Re: IIP3 measurement
You need two signal generators and one spectrum analyzer. Connect the two generators input by a combiner to the LNA input. Send the two tones at, for example, 2.4GHz (f1) and 2.41 GHz (f2), same power, and see the signal at 2.39 GHz (2*f1-f2) and at 2.42 GHz (2*f2-f1). Measure the difference level between f1 and the armonic (or f2 and armonic), called IM3. The relaptions that link the IM3 and the IIP3 is: IIP3 = input signal level + IM3/2.
There are also the network analyzer of last generation can do the IIP3 linearity measurement directly.
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