Len,

Fairchild's application note AN-393 is an informative one from the
standpoint of _transient_ switching analysis. Analysis or simulation
for impedance matching, presuming matching at a single frequency,
leans towards _steady state_ analysis.

You are right about AN-393, and the non-linearities, of course. However
when I first posted I needed a ballpark figure and the app-note gave it me. My
application is a rather mundane, fixed frequency, 10MHz frequency standard
required to drive a counter/signal generator combo and whose output should be
reasonably sinusoidal so as not to spray harmonics around the place. The
buffered or inverted output coming off the VCXO has to supply about 1V pk-pk
into 50 ohms. A 74HC04 or '07 followed by a single-section, image-parameter, pi
-section filter appears to do the job but it was just my day for being
scientific :-(


Cheers - Joe