Back on May 6 (I've been out of the office until now), Arlen said:
>One fallout of this is that I cannot create a third order IMD product if
>I do not create a second harmonic
Sorry, it ain't so.
For a transfer characteristic of the form described, the third order
components do not produce a second harmonic, but they do produce a 3rd
order IMD product. The math is too damn hard to type in here, but if you
have access to Single Sideband Principles and Circuits by Pappenfus et al.,
you'll fine the expansion on P181.
Interestingly, for 3rd order IM products, we assume a 3 to 1 relationship
between products and fundamental. It isn't quite: there's a 5th order term
involved, which for a transistor log. transfer curve introduces about a 10%
error.
Be back to e-mail Wednesday 20th. I'm off to Dyton tomorrow. I'll be with
the Sultans of Schwing in the Center Plaza on Thursday, and the Mid Western
Contesters on Friday night.
73
Peter G3RZP
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