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One additional comment on how Intercept Points are indicated (and measured). I measured and referenced the Intercept Points in the two circuits to the output of the device--thus "OIP3" means "Third Order Output Intercept", and of course the same for the second order--"OIP2" = Second Order Output Intercept.
With my test setup I'm looking at the output signals from the circuit, thus it's easiest to first determine the Output Intercept Point. And to convert to the Input Intercept Points (IIP3, IIP2), one simply subtracts the gain of the circuit from the Ouput Intercept Points. Thus, for a circuit with overall negative gain, which both these circuits had, the Input Intercept Points would be approximately 3 dB higher than the Output Intercept Points.
When comparing intercept points, it's important to know if the output or the input is being referred to; sometimes just an intercept point is given without stating which it is. In industry, normally Output Intercept Point is stated, or implied, but unless it's specifically stated as "Output" or "Input" intercept point, then you can't directly compare intercepts of other circuits.
Several ARRL publications give more information about distortion in amplifiers, intercept point, and such. The older (out of print) "Solid State Design for the Radio Amateur; any recent Handbook; the recently published "Experimental Methods in RF Design", and the one with the most extensive treatment, "Introduction to Radio Frequency Design" by Wes Hayward W7ZOI. The latter is aimed more at the engineer, with quite a bit of math, but still is readable for anyone with a basic electronics background.
73,
Steve