"Jim Pennell" wrote in message link.net...
"Tom Bruhns" Wrote:
....
?? Lots of energy in the fundamental; filter to
extract the fundamental and feed it to your
full-wave rectifier doubler.
....
So, a square wave into a diode doubler will produce only a small amount of
the second harmonic. You'd be better off running the input square wave
through a lowpass of some sort and then doubling it.

Right on, Jim. "Filter to extract the fundamental and feed it [the
fundamental] to your full-wave rectifier doubler." Of course, third
harmonic mixed with fundamental gives you second and fourth, etc., so
there's a hint that the harmonics could be useful if the phases were
right. What do you get if you feed a mixer a square wave in one port,
and the same square wave delayed by 1/4 period into the other port?

Cheers,
Tom