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Old July 9th 07, 02:23 AM posted to sci.electronics.basics,rec.radio.shortwave,rec.radio.amateur.antenna,alt.cellular.cingular,alt.internet.wireless
Bob Myers Bob Myers is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 47
Default AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency


"Jeff Liebermann" wrote in message
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Nor did I say there was. The phenomenon of interference
between two compression waves in a given medium is not
an example of "mixing."


You didn't say that. You that a beat note would be produced. From
your posting at:
http://groups.google.com/group/sci.electronics.basics/msg/f18c6dfefbd55a82
"An audible beat tone is produced by the constructive and
destructive interference between two sound waves in air."

That's wrong. There's no audible beat note produced in the air.


Sigh - which, again, is as I explained it further on. I said that
there is no actual component at the "beat" frequency. You do
HEAR a "beat," however, and that is the result of the amplitude
variation caused by the interference, as noted. You cannot hear
the beat effect (I won't use the word "tone" here, which I admit
was a possible source of confusion in the original wording) if the
two original tones are too far apart, simply because you can only
perceive such amplitude variations if they occur below a certain
rate.

I have never ever said that "mixing" (multiplication) occurs in air.
If you're going to pick apart what someone is saying, then please
read everything they've said before starting.

And whether or not you READ all the postings in a thread is one
thing - whether or not you choose to respond to a given posting
out of its context is something else entirely.

Bob M.