On Mon, 16 Feb 2004 17:02:20 GMT, "W3JDR" wrote:

I would think a "W3JDR" would know that even harmonics are *much*
harder to obtain in nonlinear multipliers.

I guessed I missed Jim's comment in the earlier post, or I would have replied earlier.
Jim, I'm not not sure what you're trying to say, but there seems to be a sarcastic undertone to the way you said it.

Only mildly so, just "funning" you ;-)


Anyway, it turns out that non-linear single-ended elements are great generators of even-order harmonics. That's why the classical HF/VHF multiplier circuit is typically a single ended transistor amplifier with output and input tuned to different frequencies. If you bias the device so it is non-linear, then it becomes a natural harmonic generator. You can enhance even-order generation and supress the odd-order generation by using a non-linear 'push-push' stage, just as you can suppress even order harmonics with a 'push-pull' stage.

In either case, the important thing to remember is that symmetrical clipping or limiting generates mostly odd-order distortion and unsymmetrical clipping or limiting generates mostly even order distortion. The quantification of this is left to those more mathematically inclined.

Joe
W3JDR

It depends on what your are starting from. If it's a sine wave, yes
even harmonics can be made from diode non-linearities.

The OP has a inverter-style XTAL oscillator, output very nearly
square.

A square wave is rich in odd harmonics, a perfect square wave has NO
even harmonics.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
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