AM electromagnetic waves: 20 KHz modulation frequencyonanastronomically-low carrier frequency
 

"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

Why can't you answer the question?
How or why do you think AM broadcasters are wasting money by generating a
carrier??

AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency
 

"Jeff Liebermann" wrote in message
...
"Bob Myers" hath wroth:

"Ron Baker, Pluralitas!" wrote in message
. ..

No nonlinearity is necessary in order to hear
a beat?
Where does the beat come from?

An audible beat tone is produced by the constructive and destructive
interference between two sound waves in air. Look at a pictorial
representation (in the time domain) of the sum of sine waves,of similar
amplitudes, one at, say, 1000 Hz and the other at 1005, and you'll
see it.

Bob M.

I beg to differ. There's no mixing happening in the air. compression
of air is very linear (Boyles Law or PV=constant). If there were
mixing, you would be able to hear the beat note when one generates two
ultrasonic tones. I belch 25KHz and 26KHz from two transducers, by
our logic, air mixing would create a 1KHz beat note. It doesn't and
you hear nothing.

What seems to be the problem here is the model of the human ear is not
what one would assume. It is NOT a broadband detector. The cochlea
cilia (hairs) resonate at individual frequencies. Each one resonantes
at only one frequency (and possibly some sub-harmonics). Therefore,
the human ear model is a collection of narrow band filters and
detectors. Unless the two frequencies involved both cause a single
cilia to simultaneously vibrate at both frequencies, there isn't going
to be any mixing. Each detector can be individually quite non-linear,
but as long as it vibrates at only one frequency, there isn't going to
be any mixing.

Well done.
Finally, someone who gets it.


Meanwhile, I would greatly appreciate it if everyone would kindly trim
quotations. This thread is becoming difficult to read. Thanks.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency
 

"isw" wrote in message
...
In article ,
Jeff Liebermann wrote:

"Bob Myers" hath wroth:

"Ron Baker, Pluralitas!" wrote in message
.. .

No nonlinearity is necessary in order to hear
a beat?
Where does the beat come from?

An audible beat tone is produced by the constructive and destructive
interference between two sound waves in air. Look at a pictorial
representation (in the time domain) of the sum of sine waves,of similar
amplitudes, one at, say, 1000 Hz and the other at 1005, and you'll
see it.

Bob M.

I beg to differ. There's no mixing happening in the air. compression
of air is very linear (Boyles Law or PV=constant).

In general, that's true, but take a look at what happens in the throats
of high-powered horn loudspeakers. You can find info in e.g. "Acoustics"
by Beranek.

Isaac

Red herring.

AM electromagnetic waves: 20 KHz modulation frequencyonanastronomically-low carrier frequency
 

"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?


There have been attempts to remove the carrier but receivers could not be
manufatured at a reasonable price that would demodulate the signal with the
fidelity of an AM BCB signal. Probably could be done today but what would
you l do with all those AM rx that suddenly dont work when the transition is
made.

AM electromagnetic waves: 20 KHz modulationfrequencyonanastronomically-low carrier frequency
 

On 7/10/07 3:26 AM, in article ,
"Jimmie D" wrote:


"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

I see Jimmie talked all around your question.

I'll answer it AGAIN, though I'm still sure your only a troll.....

DSB says nothing about the carrier; DSBSC is still DSB.

You can have DSBSC (Suppressed Carrier), DSBRC (Reduced Carrier), and DSB
with Full Carrier. You can look up the abbreviation for the latter if you
need it.

Broadcast medium wave radio, slang term "AM Radio," is DSB with full
Carrier.



There have been attempts to remove the carrier but receivers could not be
manufatured at a reasonable price that would demodulate the signal with the
fidelity of an AM BCB signal. Probably could be done today but what would
you l do with all those AM rx that suddenly dont work when the transition is
made.

AM electromagnetic waves: 20 KHz modulation frequencyonanastronomically-low carrier frequency
 

"Ron Baker, Pluralitas!" wrote in message
...

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

Obviously, since it has both sidebands. What it's
missing, vs. "normal" AM, is the carrier.

Bob M.

AM electromagnetic waves: 20 KHz modulation frequencyonanastronomically-low carrier frequency
 

In message , Don Bowey
writes
On 7/10/07 3:26 AM, in article ,
"Jimmie D" wrote:


"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

I see Jimmie talked all around your question.

I'll answer it AGAIN, though I'm still sure your only a troll.....

DSB says nothing about the carrier; DSBSC is still DSB.

You can have DSBSC (Suppressed Carrier), DSBRC (Reduced Carrier), and DSB
with Full Carrier. You can look up the abbreviation for the latter if you
need it.

Broadcast medium wave radio, slang term "AM Radio," is DSB with full
Carrier.



There have been attempts to remove the carrier but receivers could not be
manufatured at a reasonable price that would demodulate the signal with the
fidelity of an AM BCB signal. Probably could be done today but what would
you l do with all those AM rx that suddenly dont work when the transition is
made.



Just out of interest....
http://www.vkham.com/vk8da/documents...fOperation.pdf
Ian.
--

AM electromagnetic waves: 20 KHz modulation frequency on an astronomically-low carrier frequency
 

Jim Kelley wrote:

David L. Wilson wrote:

"Jim Kelley" wrote in message
...
...

sin(a) + sin(b) = 2sin(.5(a+b))cos(.5(a-b))

A plot of the function reveals that cos(.5(a-b)) describes the envelope.


Ok.

The period of the 'enveloped' waveform (or the arcane, beat

modulated waveform) then can be seen to vary continuously and
repetitiously over time - from 1/a at one limit to 1/b at the other.


?


At a particular instant in time the period does in fact equal the average
of the two. But this is true only for an instant every 1/(a-b) seconds.


??

How do you come up with anything but a period of of the average of the
two for the enveloped waveform?

The error here is in assuming that the sin and cos terms in the
equivalent expression are representative of individual waves. They
are not. The resultant wave can only be accurately described as the
sum of the constituent waves sin(a) and sin(b), or as the function
2sin(.5(a+b))cos(.5(a-b)). That function, plotted against time
appears exactly as I have described. I have simply reported what is
readily observable.

jk


I would submit you plotted it wrong and/or misinterpreted the results.

AM electromagnetic waves: 20 KHz modulationfrequencyonanastronomically-low carrier frequency
 

"Don Bowey" wrote in message
...
On 7/10/07 3:26 AM, in article ,
"Jimmie D" wrote:


"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

I see Jimmie talked all around your question.

Actually Jimmie gave a plausable reason to your statement/question that AM
broadcasters are wasting money by generating a carrier.

I'll answer it AGAIN, though I'm still sure your only a troll.....

DSB says nothing about the carrier; DSBSC is still DSB.

You still have to have a carrier to modulate.

You can have DSBSC (Suppressed Carrier), DSBRC (Reduced Carrier), and DSB
with Full Carrier. You can look up the abbreviation for the latter if you
need it.

And you still need to modulate a carrier. So your statement/question that AM
broadcasters are wasting money by generating a carrier was illogical in the
context of this thread.

Broadcast medium wave radio, slang term "AM Radio," is DSB with full
Carrier.

So then you agree that the Broadcasters are not wasting money by generating
a carrier.



There have been attempts to remove the carrier but receivers could not be
manufatured at a reasonable price that would demodulate the signal with
the
fidelity of an AM BCB signal. Probably could be done today but what would
you l do with all those AM rx that suddenly dont work when the transition
is
made.

AM electromagnetic waves: 20 KHzmodulationfrequencyonanastronomically-low carrier frequency
 

On 7/10/07 6:54 PM, in article ,
"Dana" wrote:


"Don Bowey" wrote in message
...
On 7/10/07 3:26 AM, in article ,
"Jimmie D" wrote:


"Ron Baker, Pluralitas!" wrote in message
...

"Dana" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...
Do you understand that a DSB signal *is* AM?

So all the AM broadcasters are wasting money by
generating a carrier?

How did you jump to that conclusion.

Is "DSBSC" DSB?

I see Jimmie talked all around your question.

Actually Jimmie gave a plausable reason to your statement/question that AM
broadcasters are wasting money by generating a carrier.

Actually, he talked about the topic without answering the question asked by
the OP.


I'll answer it AGAIN, though I'm still sure your only a troll.....

DSB says nothing about the carrier; DSBSC is still DSB.

You still have to have a carrier to modulate.

Obviously a reference carrier is required..... So what's your point? "DSB"
tells us NOTHING about the carrier; is it suppressed, reduced, or full in
the transmitted signal?

Maybe you should read an entire post before replying.


You can have DSBSC (Suppressed Carrier), DSBRC (Reduced Carrier), and DSB
with Full Carrier. You can look up the abbreviation for the latter if you
need it.

And you still need to modulate a carrier. So your statement/question that AM
broadcasters are wasting money by generating a carrier was illogical in the
context of this thread.

I did not ever say AM broadcasters are wasting money by generating a
carrier. Get your story straight.

You need a reference carrier for generating sidebands, but you do not "need"
to transmit the carrier unless it's required by a specific service.


Broadcast medium wave radio, slang term "AM Radio," is DSB with full
Carrier.

So then you agree that the Broadcasters are not wasting money by generating
a carrier.

Read the sentence just above your above sentence. A transmitted, full
carrier is required for the broadcast service. Other services don't require
it.



There have been attempts to remove the carrier but receivers could not be
manufatured at a reasonable price that would demodulate the signal with
the
fidelity of an AM BCB signal. Probably could be done today but what would
you l do with all those AM rx that suddenly dont work when the transition
is
made.