That's what I said Jerry....or at least tried to say. Normally, in
applications I have experience with the signals are out of phase and thus
cancel. This, in my personal view, is the most useful configuration. But,
as I said, if someone does something else with the phase (i.e., in phase
instead of out for instance) then they could add. That's why I also called
it a vector sum. Don't know why on earth you would do that, but I suppose
someone could be perverse ! :) If they then add, or partially add, then it
just gets a little louder, and people might have trouble discerning that, as
per the complaints. On the other hand, most of us can easily discern the
difference between a signal, and No signal.
73 de Gary, AA2IZ
----- Original Message -----
From: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
To: <tentec@contesting.com>
Sent: Thursday, May 31, 2007 10:06 PM
Subject: Re: [TenTec] CW Tuning with Omni 6 Plus
> On Thu, 2007-05-31 at 21:45 -0400, Gary Hoffman wrote:
> > That's right. A zero beat means that the two tones are identical and so
> > their vector sum is zero. Hence no output. Unless of course one does
> > something odd with the phase of the two signals. Is that being done
here ?
> >
> > 73 de Gary, AA2IZ
> >
> To the contrary, when two signals are on exactly the same frequency the
> need not be out of phase, they can have any relative phase angle and
> when in phase they will add, when perfectly out of phase AND the same
> amplitude they will cancel. When their frequencies differ slightly all
> amplitudes will be heard from cancellation or near cancellation to
> addition. When there is no perception of change of amplitude they they
> are in perfect zero beat. If they go from peak through the near
> cancellation back to peak in 1 second that's a frequency difference of 1
> Hz which is good enough for most ham operations...
>
> In graphic vector sums, think of it as one vector fixed with the second
> vector's tail anchored to the head of the first vector and swinging
> around that anchor at the difference frequency.
> --
> 73, Jerry, K0CQ,
> All content copyright Dr. Gerald N. Johnson, electrical engineer
>
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>
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