Andy Thanks for your cents, rather dollars.

PS there is internal quadrature pll in ad607.

MAc


Andy responds;

Ok.. I admit that I didn't go find the AD607 and study it before
replying
to Mac... However,,, I'll bet you a dollar that the fellow who wrote
the
app note that Mac refers to has a hell of a lot less experience than
either Mac or myself..... not that I would expect a young app note
writer to overstate the applications of his product ( big damn grin
)...
The AD606 really makes a great tie-tac if you glue an alligator clip
to it, tho I've never actually seen one for sale... :)))))))

if the gilbert cell, or single ended long tailed pair multiplier
used as a
quad detector allows external coupling to the ports, it can be used as
a BFO for CW or SSB,..., HOWEVER, having a limiting stage in the
linear path of such a device is NOT a great idea.... Sure, it can be
made
to work, but..... well, heck... I've built a LOT of things that were
really
bad ideas, and I try not to duplicate them again, or tell others about

them.... especially in app notes that I've made input to......
I've seen the MC3372 used as an SSB receiver in either Ham Radio
or some such.... and I never seriously considered doing it myself since
the limitations were so obvious....

An 811A can be used a a product detector also, but the
manufacturers
don't advertise it as such,...... because it is a REALLY BAD idea....
If a fellow wants a simple CW/SSB receiver, a much better idea is to
use something like an NE602..... I've done that, for a home project ,
and
it works OK,..... but certainly not something I'd try to produce as a
receiver for Bendix, Texas Instruments, or Raytheon...... There's a
limit
to how far one should stretch an application.....

Thanks Mac, for your input. I bet we agree on almost
everything.....

Andy W4OAH