wrote:
I've heard that high side mixing is preferred to low side
mixing because the LO harmonics will be higher and less
likely to cause problems.

It also seems to me that (f1 + f2) is typically discarded
and what's used is just the (f1 - f2).

Any truth to either of these impressions? If so, what's
the rational?

Depending on the availability of off the shelf VCO parts
one might what to use (f1 + f2) or low side mixing and I
was just curious what (if any) additional problems I should
look out for.

-- John


It's easier to dodge harmonics and higher-order mixing products.

For _any_ IF/LO combination you should make a table of the possible
mixing products of the first few harmonics of your RF range with
_several_ harmonics of your LO range (most modern mixers generate _lots_
of odd harmonics of the LO internally). If any of these products other
than the intended pair span the IF then you'll have problems with
spurious mixing.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html