Is it possible to generate a beating wave ?
Giorgis
Were can I find some info on the topic ?
Thanks
Giorgis
Leon
Giorgis wrote:
> Is it possible to generate a beating electromagnetic wave ?
> Were can I find some info on the topic ?
Not directly, AFAIK. You could receive it with an antenna, beat it with
another signal using a mixer and retransmit it.
Leon
colin
news:1162377906....@f16g2000cwb.googlegroups.com...
> Is it possible to generate a beating electromagnetic wave ?
> Were can I find some info on the topic ?
2 waves of slightly different frequency will beat together if thats what you
mean ?
therefore you just need to generate and transmit 2 such frequencies.
Colin
Giorgis
same antena source ?
Are there any similar applications ?
Giorgis
Ed Douglas
<leon....@bulldoghome.com> writes
Of course it's possible - 2 transmitters on the same frequency will
produce a beating wave. This technique is used in quasi-sync mobile
radio networks to produce wide area coverage where the beat frequency is
normally arranged to be a few kHz so that it is above the audio range
but still within the receiver capture range.
--
Ed Douglas
colin
> I'd like to do it in a free spectrum. do they have to come from the
> same antena source ?
> Are there any similar applications ?
>
> Giorgis
I dont know what your application is so I cant answer.
Colin =^.^=
Don Bowey
"colin" <no.spam...@ntlworld.com> wrote:
You, of course, mean that two different frequency signals can beat together
within the detector of an appropriate receiver. Without a detector, they
don't "beat."
Don
Don Lancaster
Question is more subtle than that.
If two waves are to interact and produce sum and difference frequencies,
a nonlinear media or component is required.
--
Many thanks,
Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: d...@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Leon
I don't think that's what he meant. He is asking whether two waves can
beat without a receiver, I don't think that they can.
Leon
Giorgis
Maybe my knowledge is a bit hobbyish in the field. What I would like
to do is create an elctromagnetic wave that has a carier wave on it
that appears to travel along it at a speed of my choosing.
I suspected that if add two waves to each other that have a very close
freequency, I will get the wave of my choice
YES ... NO ?
Giorgis
Al
"Giorgis" <giorgis...@gmail.com> wrote:
Take a wave and split it into two streams. They will be of the same
amplitude and frequency. Slowly shift the phase of one with respect to
the other and add the waves, you will get a wave that beats at the
frequency of the phase shift.
Al
colin
news:1162404157....@e3g2000cwe.googlegroups.com...
I think one assumed that he would be sensing them with some sort of
detector,
but its such a vague question,
if you look at 2 such waves on an oscilloscope you can see them beating as
such,
although to extract the beat frequency itself you do need a non linear
detector.
Colin =^.^=
john jardine
"colin" <no.spam...@ntlworld.com> wrote in message
news:Clp2h.36215$t6....@newsfe4-win.ntli.net...
couple of spectral emission lines that could mix down into microwave
frequencies, via the non linear gas plasma.
john
--
Posted via a free Usenet account from http://www.teranews.com
Giorgis
after is doing it with electronics.
Giorgis
Don Lancaster
If you multiply the two waves, or add then in a nonlinear media, sum and
difference frequencies may results.
Giorgis
> If you linearly add the two waves, nothing will happen.
> If you multiply the two waves, or add then in a nonlinear media, sum and
> difference frequencies may results.
>
Coudl you explain what you mean by linearly add two waves
or Multiply or add them in a nonlinear media ?
Regards
Giorgis
Don Lancaster
> On 1 Nov 2006 02:45:06 -0800, "Giorgis" <giorgis...@gmail.com>
> wrote:
>
>
>>Is it possible to generate a beating electromagnetic wave ?
>>Were can I find some info on the topic ?
>
>
> generating a musical sound. My magnetic fields mix in the air with two
> oscillator coils in proximity to one another. A diode RC combo detects
> the amplitude modulation created. Here is a link to my homemade
> circuit board webpage using the heterodyne principle.
>
> http://www.oldtemecula.com/theremin/ultimate2b/index.htm
>
>
>
> * * *
> Christopher
>
> Temecula CA.USA
> http://www.oldtemecula.com
Unless your air is very strange, very little "mixing" takes place in the
air.
The "mixing" is directly caused by the diode nonlinearity.
--
Many thanks,
Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: d...@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Don Lancaster
Follows from fundamental trig identities.
Especially sin(u) + sin(v) = sin(u) + sin(v) with no change in a linear
system
But
sin(u)sin(v) = 1/2 [cos (u-v) - cos (u+v) ] with sum and difference
frequencies resulting from a multiplication or a nonlinear system.
True 4 quadrant multiplication can give near 100% conversion.
Nonlinear systems will typically convert a lot less.
Unless at least one of the waveforms gets squashed, there will be no
mixing and no cross products.
--
Many thanks,
Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: d...@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
John Fields
wrote:
>
>> If you linearly add the two waves, nothing will happen.
>> If you multiply the two waves, or add then in a nonlinear media, sum and
>> difference frequencies may results.
>>
>
>Coudl you explain what you mean by linearly add two waves
>or Multiply or add them in a nonlinear media ?
---
In water, if you transmit two carriers, simultaneously, where either
(or both) of their amplitudes compresses the water to the point
where it goes nonlinear, you'll get heterodynes.
In air, the point of compression where nonlinearity will allow that
to happen approaches the vanishing point.
--
JF
Giorgis
Don Lancaster wrote:
> christopher wrote:
> > On 1 Nov 2006 02:45:06 -0800, "Giorgis" <giorgis...@gmail.com>
> > wrote:
> >
> >
> >>Is it possible to generate a beating electromagnetic wave ?
> >>Were can I find some info on the topic ?
> >
> >
> > Google "heterodyne". I do something similar to what you mention in
> > generating a musical sound. My magnetic fields mix in the air with two
> > oscillator coils in proximity to one another. A diode RC combo detects
> > the amplitude modulation created. Here is a link to my homemade
> > circuit board webpage using the heterodyne principle.
> >
> > http://www.oldtemecula.com/theremin/ultimate2b/index.htm
> >
> >
> >
> > * * *
> > Christopher
> >
> > Temecula CA.USA
> > http://www.oldtemecula.com
> Unless your air is very strange, very little "mixing" takes place in the
> air.
>
> The "mixing" is directly caused by the diode nonlinearity.
>
?! What is "mixing" by your definition ?
Giorgis
Le Chaud Lapin
> Don Lancaster wrote:
> > christopher wrote:
> > > On 1 Nov 2006 02:45:06 -0800, "Giorgis" <giorgis...@gmail.com>
> > > wrote:
> > >
> > >
> > >>Is it possible to generate a beating electromagnetic wave ?
> > >>Were can I find some info on the topic ?
> > >
> > >
> > > Google "heterodyne". I do something similar to what you mention in
> > > generating a musical sound. My magnetic fields mix in the air with two
> > > oscillator coils in proximity to one another. A diode RC combo detects
> > > the amplitude modulation created. Here is a link to my homemade
> > > circuit board webpage using the heterodyne principle.
> > >
> > > http://www.oldtemecula.com/theremin/ultimate2b/index.htm
> > >
> > >
> > >
> > > * * *
> > > Christopher
> > >
> > > Temecula CA.USA
> > > http://www.oldtemecula.com
> > Unless your air is very strange, very little "mixing" takes place in the
> > air.
> >
> > The "mixing" is directly caused by the diode nonlinearity.
> >
>
> ?! What is "mixing" by your definition ?
>
> Is it possible to generate a beating electromagnetic wave ?
> Were can I find some info on the topic ?
>
>
> Giorgis
Mixing is a multiplicative phenonmenon, not additive. As Don pointed
out, you do not get mixing by adding two signals. That can only come
from multiplication.
Incidentally, I Googled for a site that would illustrate this, and
found this link, which appears to be incorrect:
http://hyperphysics.phy-astr.gsu.edu/hbase/audio/sumdif.html. It
states: "When you superimpose two sine waves of different frequencies,
you get components at the sum and difference of the two frequencies."
This is not true. "Components" is a word typical reserved for
superposition. If you superpose two signals x1(t) and x2(t), what you
get in a linear medium with unity gain and zero phase is is the sum
xs(t) = x1(t) + x2(t). You do not get "components at the sum and
difference frequencies". I think the confusion accidentally being
promulgated by the physicists has to do with their *mixing* their
understanding of physics with their understanding of physiology.
So free space is a linear medium and must abide by the principle of
superposition. Two waves flowing in free space must interact in an
additive manner, and each must behave in this medium as if the other
did not exist.
Consider two waves, S1 and S2, represented by their Poynting
vectors:http://en.wikipedia.org/wiki/Poynting_vector
S1 = E1xH1
S2 = E2xH2
Then, by superposition,
S3 = S1 + S2
and must be equal to E1xH1 + E2xH2. *Additionally* superposition
requires that individual E-fields and H-fields add:
E3(r, t) = E1(r, t) + E2(r, t)
H3(r, t) = H1(r, t) + H2(r, t)
But, when two signals "beat", it is the result of multiplication. The
sum and difference signals that result can almost be seen by eyeballing
the definition of cosine using Euler's formula:
http://en.wikipedia.org/wiki/Euler's_formula.
I think the so-called "beating" to "generate" different frequencies is
a physiological phenonmenon, a human perception. For example, if the
ear, which is notoriously non-linear, has the ability to act as an
envolope detector (http://en.wikipedia.org/wiki/Envelope_detector) then
that would explain why so many people swear that two additive signals
produce a different frequency altogether, when they are not: the ear
samples the peaks of the multiplicative signal, which is
mathematicallly equivalent to the two signals whose frequencies are
close.
-Le Chaud Lapin-