On Mon, 16 Feb 2004 13:03:46 -0600, John Fields
posted this:


Starting with a perfect square wave at f1, bang the hell out of a diode
with it, and then bandpass it and the 3rd harmonic (f2) separately, then
mix them to get f1, f2, f1+f2, and f1-f2. Using a doubly balanced mixer
will get rid of f1 and f2, then notching out f1+f2 will leave f1-f2,
which will be 2f1, that non-existent second harmonic.

What purpose does the diode serve? You're already starting with a
"perfect" square wave.

OTOH, if you have had some bad experiences with diodes in the past, I
can easily understand your tendency to abuse them as often as you can.

Jim