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

In article <468f14f2$0$16528$4c368faf@roadrunner.com>,
"Ron Baker, Pluralitas!" <this@aint.me> wrote:

> "isw" <isw@witzend.com> wrote in message
> news:isw-67F596.12192706072007@newsgroups.comcast.net...
> > In article <468dcf2b$0$16588$4c368faf@roadrunner.com>,
> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
> >
> >> "isw" <isw@witzend.com> wrote in message
> >> news:isw-15D472.09430705072007@newsgroups.comcast.net...
> >> > In article <468cf7f7$0$16602$4c368faf@roadrunner.com>,
> >> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
> >> >
> >> >> "isw" <isw@witzend.com> wrote in message
> >> >> news:isw-FB6C92.00093805072007@newsgroups.comcast.net...
> >> >> > In article <468bdadd$0$20558$4c368faf@roadrunner.com>,
> >> >> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
> >> >>
> >> >> <snip>
> >> >>
> >> >> >> >>
> >> >> >> >> While it might not be obvious, the two cases I
> >> >> >> >> described are basically identical. And this
> >> >> >> >> situation occurs in real life, i.e. in radio signals,
> >> >> >> >> oceanography, and guitar tuning.
> >> >> >> >
> >> >> >> > The beat you hear during guitar tuning is not modulation; there
> >> >> >> > is
> >> >> >> > no
> >> >> >> > non-linear process involved (i.e. no multiplication).
> >> >> >> >
> >> >> >> > Isaac
> >> >> >>
> >> >> >> In short, the human auditory system is not linear.
> >> >> >> It has a finite resolution bandwidth. It can't resolve
> >> >> >> two tones separted by a few Hertz as two separate tones.
> >> >> >> (But if they are separted by 100 Hz they can easily
> >> >> >> be separated without hearing a beat.)
> >> >> >
> >> >> > Two tones 100 Hz apart may or may not be perceived separately;
> >> >> > depends
> >> >> > on a lot of other factors. MP3 encoding, for example, depends on the
> >> >> > ear's (very predictable) inability to discern tones "nearby" to
> >> >> > other,
> >> >> > louder ones.
> >> >>
> >> >> I'll remember that the next time I'm tuning
> >> >> an MP3 guitar.
> >> >>
> >> >> >
> >> >> >> The same affect can be seen on a spectrum analyzer.
> >> >> >> Give it two frequencies separated by 1 Hz. Set the
> >> >> >> resolution bandwidth to 10 Hz. You'll see the peak
> >> >> >> rise and fall at 1 Hz.
> >> >> >
> >> >> > Yup. And the spectrum analyzer is (hopefully) a very linear system,
> >> >> > producing no intermodulation of its own.
> >> >> >
> >> >> > Isaac
> >> >>
> >> >> What does a spectrum analyzer use to arive at
> >> >> amplitude values? An envelope detector?
> >> >> Is that linear?
> >> >
> >> > I'm sure there's more than one way to do it, but I feel certain that
> >> > any
> >>
> >> Which of them is linear?
> >
> > A well-designed filter running into a bolometer would be. You can make
> > the filter narrow enough to respond to only one frequency component at
>
> Any real spectrum analyzer has a lower limit
> to its resolution bandwidth, does it not?
> The resolution bandwidth of the human ear is non-zero
> and not really adjustable, is it not?
>
> > the time, and a bolometer just turns the signal power into heat; nothing
> > nonlinear there...
>
> Really?
> You said you are a physicist/engineer.
> What does "linear" mean?

Let's not get too far off the subject here. We were discussing whether
the "tuning beat" that you use to tune a musical instrument involved a
nonlinear process (ie. "modulation"). I said that it does not, and that
it could be detected by instrumentation which was proveably linear (i.e.
not "perfectly" linear, because that's not required, but certainly
linear enough to discount the requirement for "modulation").

That's all.

Isaac

In article <468f07a0$0$24739$4c368faf@roadrunner.com>,
"Ron Baker, Pluralitas!" <this@aint.me> wrote:

> "isw" <isw@witzend.com> wrote in message
> news:isw-9D8AE6.10201105072007@newsgroups.comcast.net...
> > In article <468d0174$0$3183$4c368faf@roadrunner.com>,
> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
> >
> >> "John Fields" <jfields@austininstruments.com> wrote in message
> >> news:8ktp839la05dj6t049kidjbpkj7rkf98ii@4ax.com...
> >> > On Thu, 5 Jul 2007 00:00:45 -0700, "Ron Baker, Pluralitas!"
> >>
> >> <snip>
> >>
> >> >>>>>
> >> >>>>> When AM is correctly accomplished (a single voiceband signal is
> >> >>>>> modulated
> >> >>>>
> >> >>>> The questions I posed were not about AM. The
> >> >>>> subject could have been viewed as DSB but that
> >> >>>> wasn't the specific intent either.
> >> >>>
> >> >>> What was the subject of your question?
> >> >>
> >> >>Copying from my original post:
> >> >>
> >> >>Suppose you have a 1 MHz sine wave whose amplitude
> >> >>is multiplied by a 0.1 MHz sine wave.
> >> >>What would it look like on an oscilloscope?
> >> >>What would it look like on a spectrum analyzer?
> >> >>
> >> >>Then suppose you have a 1.1 MHz sine wave added
> >> >>to a 0.9 MHz sine wave.
> >> >>What would that look like on an oscilloscope?
> >> >>What would that look like on a spectrum analyzer?
> >> >
> >> > ---
> >> > The first example is amplitude modulation precisely _because_ of the
> >>
> >> Is there multiplication in DSB? (double sideband)
> >
> > Yes, and in fact, that multiplication referred to above creates a
> > DSB-suppressed-carrier signal. To get "real" AM, you need to add back
> > the carrier *at the proper phase*.
>
> So does the multiplication in the first example really make
> it amplitude modulation?

Yes, because the output signal varies in amplitude with modulation. For
suppressed carrier SSB or DSB, the output is zero when there's no
modulating signal, while for "traditional AM", the output is 50% for no
modulation.

Compare to FM or PM, where the output is constant regardless of the
modulation level. True, FM has a lot of sidebands that vary in
amplitude, but if you add them all together, the output is constant.

Run an SSB, DSB, or AM rig into a dummy load and it'll get hotter with
modulation, while with FM the temperature won't change.

--

But recall that if you take that DSB signal you got by multiplication,
and reinject the carrier in quadrature, you no longer have amplitude
modulation.

Isaac

"isw" <isw@witzend.com> wrote in message
news:isw-BAF518.10432307072007@newsgroups.comcast.net...
> In article <468f14f2$0$16528$4c368faf@roadrunner.com>,
> "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>
>> "isw" <isw@witzend.com> wrote in message
>> news:isw-67F596.12192706072007@newsgroups.comcast.net...
>> > In article <468dcf2b$0$16588$4c368faf@roadrunner.com>,
>> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>> >
>> >> "isw" <isw@witzend.com> wrote in message
>> >> news:isw-15D472.09430705072007@newsgroups.comcast.net...
>> >> > In article <468cf7f7$0$16602$4c368faf@roadrunner.com>,
>> >> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>> >> >
>> >> >> "isw" <isw@witzend.com> wrote in message
>> >> >> news:isw-FB6C92.00093805072007@newsgroups.comcast.net...
>> >> >> > In article <468bdadd$0$20558$4c368faf@roadrunner.com>,
>> >> >> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>> >> >>
>> >> >> <snip>
>> >> >>
>> >> >> >> >>
>> >> >> >> >> While it might not be obvious, the two cases I
>> >> >> >> >> described are basically identical. And this
>> >> >> >> >> situation occurs in real life, i.e. in radio signals,
>> >> >> >> >> oceanography, and guitar tuning.
>> >> >> >> >
>> >> >> >> > The beat you hear during guitar tuning is not modulation;
>> >> >> >> > there
>> >> >> >> > is
>> >> >> >> > no
>> >> >> >> > non-linear process involved (i.e. no multiplication).
>> >> >> >> >
>> >> >> >> > Isaac
>> >> >> >>
>> >> >> >> In short, the human auditory system is not linear.
>> >> >> >> It has a finite resolution bandwidth. It can't resolve
>> >> >> >> two tones separted by a few Hertz as two separate tones.
>> >> >> >> (But if they are separted by 100 Hz they can easily
>> >> >> >> be separated without hearing a beat.)
>> >> >> >
>> >> >> > Two tones 100 Hz apart may or may not be perceived separately;
>> >> >> > depends
>> >> >> > on a lot of other factors. MP3 encoding, for example, depends on
>> >> >> > the
>> >> >> > ear's (very predictable) inability to discern tones "nearby" to
>> >> >> > other,
>> >> >> > louder ones.
>> >> >>
>> >> >> I'll remember that the next time I'm tuning
>> >> >> an MP3 guitar.
>> >> >>
>> >> >> >
>> >> >> >> The same affect can be seen on a spectrum analyzer.
>> >> >> >> Give it two frequencies separated by 1 Hz. Set the
>> >> >> >> resolution bandwidth to 10 Hz. You'll see the peak
>> >> >> >> rise and fall at 1 Hz.
>> >> >> >
>> >> >> > Yup. And the spectrum analyzer is (hopefully) a very linear
>> >> >> > system,
>> >> >> > producing no intermodulation of its own.
>> >> >> >
>> >> >> > Isaac
>> >> >>
>> >> >> What does a spectrum analyzer use to arive at
>> >> >> amplitude values? An envelope detector?
>> >> >> Is that linear?
>> >> >
>> >> > I'm sure there's more than one way to do it, but I feel certain that
>> >> > any
>> >>
>> >> Which of them is linear?
>> >
>> > A well-designed filter running into a bolometer would be. You can make
>> > the filter narrow enough to respond to only one frequency component at
>>
>> Any real spectrum analyzer has a lower limit
>> to its resolution bandwidth, does it not?
>> The resolution bandwidth of the human ear is non-zero
>> and not really adjustable, is it not?
>>
>> > the time, and a bolometer just turns the signal power into heat;
>> > nothing
>> > nonlinear there...
>>
>> Really?
>> You said you are a physicist/engineer.
>> What does "linear" mean?
>
> Let's not get too far off the subject here. We were discussing whether
> the "tuning beat" that you use to tune a musical instrument involved a
> nonlinear process (ie. "modulation").

Then linearity is at the core of the matter.
What does "linear" (or "nonlinear") mean to you?

> I said that it does not, and that
> it could be detected by instrumentation which was proveably linear (i.e.
> not "perfectly" linear, because that's not required, but certainly
> linear enough to discount the requirement for "modulation").

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

>
> That's all.
>
> Isaac

"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
news:468fe7df$0$16560$4c368faf@roadrunner.com...

First of all, do you think you could possibly learn to trim your posts?

> 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.

Tommy Tootles wrote:

> [stuff]

Your expansion of the original and simple question into a convoluted and
obfuscated mess shows an outstanding knack for skills related to the
psychotic ... however, it also shows you to be an idiot.

Hey, are you attempting to fake a mental disorder so you can get off
welfare and onto SSI?

Sharpen your razor blade, return to the mental hospital--begin splitting
hairs ...

JS

On Jul 7, 12:44 pm, John Smith I <assemblywiz...@gmail.com> wrote:
> Tommy Tootles wrote:
>
> > [stuff]
>
> Your expansion of the original and simple question into a convoluted and
> obfuscated mess shows an outstanding knack for skills related to the
> psychotic ... however, it also shows you to be an idiot.
>
> Hey, are you attempting to fake a mental disorder so you can get off
> welfare and onto SSI?
>
> Sharpen your razor blade, return to the mental hospital--begin splitting
> hairs ...
>
> JS

Ah the War-of-the-Words continues ~ RHF

In article <468f0515$0$30690$4c368faf@roadrunner.com>,
"Ron Baker, Pluralitas!" <this@aint.me> wrote:

--snippage--

> >> That doesn't explain why the effect would come and go.
> >
> > I don't understand what effect you're referring to here.
>
> When I was tuned to the 3rd harmonic sometimes
> I would hear it and sometimes not.
> It would come and go rather abruptly. It didn't seem
> to be gradual fading.

Especially if the RF field is strong, there are a lot of mechanisms
which can create harmonics after the signal leaves the transmitter --
rusty fencing, or tooth fillings, for example. I can see how one of
those could be intermittent.

> >> But once again you have surprised me.
> >> Your explanation of the non-multiplied sidebands,
> >> while qualitative and incomplete, is sound.
> >
> > I'm a physicist/engineer, and have been for a long time. I have always
>
> The you understand Fourier transforms and convolution.

I suppose so; I've spent over fifteen years poking around in the
entrails of MPEG...

> > I don't understand what you are saying here either. And in my
> > experience, the term "modulation index" is more likely to show up in a
> > discussion of FM or PM than AM; are you using it interchangeably with
> > "modulation percentage"?

As I suspected -- just different words for the same thing.

So:

>> It looks to me that the tripple frequency sidebands
>> are there but the basic sidebands dominate.
>> Especially at lower modulation indexes.

With well-designed gear (or theoretically), for AM there will be no
other frequencies present except for the carrier and the ones
represented by the Fourier spectrum of the modulation -- one set either
side of the carrier. That is only true, of course, as long as there is
no overmodulation; that creates a *lot* of other junk, because there are
periods where the carrier is entirely cut off.

So I still don't understand what you mean by "triple frequency
sidebands" or "basic sidebands".

As I said in another post, modulation is a "rate effect", so there never
should be any frequencies generated at multiples of the sidebands
surrounding the fundamental; instead they are always identically as far
from the harmonics as they are from the fundamental. Is that what you
are calling "triple frequency sidebands"?

Isaac

On Jun 29, 7:41 pm, Radium <gluceg...@gmail.com> wrote:
> Hi:
>
> Please don't be annoyed/offended by my question as I decreased the
> modulation frequency to where it would actually be realistic.
>
> I have a very weird question about electromagnetic radiation,
> carriers, and modulators.
>
> Is it mathematically-possible to carry a modulator signal [in this
> case, a pure-sine-wave-tone] with a frequency of 20 KHz and an
> amplitude of 1-watt-per-meter-squared on a AM carrier signal whose
> frequency is 10^-(1,000,000,000-to-the-power-10^1,000,000,000)
> nanocycle* every 10^1,000,000,000-to-the-power-10^1,000,000,000 giga-
> eons and whose amplitude is a minimum of 10^1,000,000,000-to-the-
> power-10^1,000,000,000 gigaphotons per 10^-(1,000,000,000-to-the-
> power-10^1,000,000,000) nanosecond?
>
> If it is not mathematically-possible, then please explain why.
>
> 10^-(1,000,000,000-to-the-power-10^1,000,000,000) second is an
> extremely short amount of time. 10^-(1,000,000,000-to-the-
> power-10^1,000,000,000) nanosecond is even shorter because a
> nanosecond is shorter than a second.
>
> Giga-eon = a billion eons
>
> Eon = a billion years
>
> *nanocycle = billionth of a cycle
>
> Gigaphoton = a billion photons
>
> 10^1,000,000,000-to-the-power-10^1,000,000,000 -- now that is one
> large large number.
>
> 10^1,000,000,000 = 10-to-the-power-1,000,000,000
>
> So you get:
>
> (10-to-the-power-1,000,000,000) to the power (10-to-the-
> power-1,000,000,000)
>
> 10^-(1,000,000,000-to-the-power-10^1,000,000,000) = 10^-(10-to-the-
> power-1,000,000,000)-to-the-power-(10-to-the-power-1,000,000,000)
>
> 10^-(10-to-the-power-1,000,000,000) to the power (10-to-the-
> power-1,000,000,000) is an extremely small number at it equals 10-to-
> the-power-NEGATIVE-[(10-to-the-power-1,000,000,000) to the power (10-
> to-the-power-1,000,000,000)]
>
> No offense but please respond with reasonable answers & keep out the
> jokes, off-topic nonsense, taunts, insults, and trivializations. I am
> really interested in this.
>
> Thanks,
>
> Radium

WHAT WAS "RADIUM'S" ORIGINAL QUESTION ?
-and- HAS IT BEEN ANSWERED ?

Hi:

Please don't be annoyed/offended by my question as I decreased the
modulation frequency to where it would actually be realistic.


I have a very weird question about electromagnetic radiation,
carriers, and modulators.


Is it mathematically-possible to carry a modulator signal [in this
case, a pure-sine-wave-tone] with a frequency of 20 KHz and an
amplitude of 1-watt-per-meter-squared on a AM carrier signal whose
frequency is 10^-(1,000,000,000-to-the-power-10^1,000,000,000)
nanocycle* every 10^1,000,000,000-to-the-power-10^1,000,000,000 giga-
eons and whose amplitude is a minimum of 10^1,000,000,000-to-the-
power-10^1,000,000,000 gigaphotons per 10^-(1,000,000,000-to-the-
power-10^1,000,000,000) nanosecond?


If it is not mathematically-possible, then please explain why.


10^-(1,000,000,000-to-the-power-10^1,000,000,000) second is an
extremely short amount of time. 10^-(1,000,000,000-to-the-
power-10^1,000,000,000) nanosecond is even shorter because a
nanosecond is shorter than a second.


Giga-eon = a billion eons


Eon = a billion years


*nanocycle = billionth of a cycle


Gigaphoton = a billion photons


10^1,000,000,000-to-the-power-10^1,000,000,000 -- now that is one
large large number.


10^1,000,000,000 = 10-to-the-power-1,000,000,000


So you get:


(10-to-the-power-1,000,000,000) to the power (10-to-the-
power-1,000,000,000)


10^-(1,000,000,000-to-the-power-10^1,000,000,000) = 10^-(10-to-the-
power-1,000,000,000)-to-the-power-(10-to-the-power-1,000,000,000)


10^-(10-to-the-power-1,000,000,000) to the power (10-to-the-
power-1,000,000,000) is an extremely small number at it equals 10-to-
the-power-NEGATIVE-[(10-to-the-power-1,000,000,000) to the power (10-
to-the-power-1,000,000,000)]


No offense but please respond with reasonable answers & keep out the
jokes, off-topic nonsense, taunts, insults, and trivializations. I am
really interested in this.


Thanks,


Radium

"Bob Myers" <nospamplease@address.invalid> wrote in message
news:f6oqdv$npt$1@usenet01.boi.hp.com...
>
> "Ron Baker, Pluralitas!" <this@aint.me> wrote in message
> news:468fe7df$0$16560$4c368faf@roadrunner.com...
>
> First of all, do you think you could possibly learn to trim your posts?
>
>> 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.
>

How come you don't hear a 200 Hz beat
with a 1000 Hz tone and a 1200 Hz tone?

isw wrote:
> Especially if the RF field is strong, there are a lot of mechanisms
> which can create harmonics after the signal leaves the transmitter --
> rusty fencing, or tooth fillings, for example.

What we used to call miscellaneous metallic junction intermod.

"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
news:468ff303$0$24708$4c368faf@roadrunner.com...
>
> "Bob Myers" <nospamplease@address.invalid> wrote in message
> news:f6oqdv$npt$1@usenet01.boi.hp.com...
>>
>> "Ron Baker, Pluralitas!" <this@aint.me> wrote in message
>> news:468fe7df$0$16560$4c368faf@roadrunner.com...
>>
>> First of all, do you think you could possibly learn to trim your posts?

Apparently, no, you can't. Too lazy to take the trouble to
perform this common courtesy, or what?

>> 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.
>>
>
> How come you don't hear a 200 Hz beat
> with a 1000 Hz tone and a 1200 Hz tone?

For the simple reason that there isn't actually a "tone" involved -
in other words, there is no actual signal at the difference frequency.
There can't be, since there is no "mixing" (multiplication) of the
two original tones. The "beat" is really just the perception of
the amplitude variation caused by the interference previously
mentioned. You cannot sense such variations if they occur
rapidly enough, any more than you can detect the flicker of a
light source which is varying rapidly enough.

Bob M.

That's easy. Radium has never actually had an original
question. All of his questions are either rehashing very
well-understood situations, or are utterly nonsensical and
therefore not answerable AS legitimate questions.

Bob M.

RHF wrote:

> WHAT WAS "RADIUM'S" ORIGINAL QUESTION ?
> -and- HAS IT BEEN ANSWERED ?

Does it matter ?

It's only attention seeking.

Graham

On Jul 7, 4:08 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> RHF wrote:
> > WHAT WAS "RADIUM'S" ORIGINAL QUESTION ?
> > -and- HAS IT BEEN ANSWERED ?
>

- Does it matter ?
-
- It's only attention seeking.
-
- Graham

Graham - Thank You for the Attention :o) ~ RHF
- - - You are Reply # 228 . . . and still Counting.

"Bob Myers" <nospamplease@address.invalid> wrote in message
news:f6otp9$qtt$1@usenet01.boi.hp.com...
>
> "Ron Baker, Pluralitas!" <this@aint.me> wrote in message
> news:468ff303$0$24708$4c368faf@roadrunner.com...
>>
>> "Bob Myers" <nospamplease@address.invalid> wrote in message
>> news:f6oqdv$npt$1@usenet01.boi.hp.com...
>>>
>>> "Ron Baker, Pluralitas!" <this@aint.me> wrote in message
>>> news:468fe7df$0$16560$4c368faf@roadrunner.com...
>>>
>>> First of all, do you think you could possibly learn to trim your posts?
>
> Apparently, no, you can't. Too lazy to take the trouble to
> perform this common courtesy, or what?

You could always plonk me.

>
>>> 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.
>>>
>>
>> How come you don't hear a 200 Hz beat
>> with a 1000 Hz tone and a 1200 Hz tone?
>
> For the simple reason that there isn't actually a "tone" involved -
> in other words, there is no actual signal at the difference frequency.
> There can't be, since there is no "mixing" (multiplication) of the
> two original tones.

There is no multiplication of 1000 Hz and 1005 Hz
either, is there? Why don't you hear 1000 Hz and
1005 Hz rather than a single tone varying in amplitude?

> The "beat" is really just the perception of
> the amplitude variation caused by the interference previously
> mentioned. You cannot sense such variations if they occur
> rapidly enough, any more than you can detect the flicker of a
> light source which is varying rapidly enough.
>
> Bob M.

Could it be that the human auditory system is not
linear?

"Don Bowey" <dbowey@comcast.net> wrote in message
news:C2B403C2.6DC94%dbowey@comcast.net...
> On 7/4/07 8:42 PM, in article 468c6838$0$4664$4c368faf@roadrunner.com,
> "Ron
> Baker, Pluralitas!" <this@aint.me> wrote:
>
>>
>> "Don Bowey" <dbowey@comcast.net> wrote in message
>> news:C2B16AE5.6D5BC%dbowey@comcast.net...
>>> On 7/4/07 10:16 AM, in article 468bd5ad$0$16531$4c368faf@roadrunner.com,
>>> "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>>>
>>>>
>>>> "Don Bowey" <dbowey@comcast.net> wrote in message
>>>> news:C2B1129D.6D573%dbowey@comcast.net...
>>>>> On 7/4/07 7:52 AM, in article
>>>>> 468bb3c0$0$24780$4c368faf@roadrunner.com,
>>>>> "Ron
>>>>> Baker, Pluralitas!" <this@aint.me> wrote:
>>>>
>>>> <snip>
>>>>
>>>>>>
>>>>>> cos(a) * cos(b) = 0.5 * (cos[a+b] + cos[a-b])
>>>>>>
>>>>>> Basically: multiplying two sine waves is
>>>>>> the same as adding the (half amplitude)
>>>>>> sum and difference frequencies.
>>>>>
>>>>> No, they aren't the same at all, they only appear to be the same
>>>>> before
>>>>> they are examined. The two sidebands will not have the correct phase
>>>>> relationship.
>>>>
>>>> What do you mean? What is the "correct"
>>>> relationship?
>>>>
>>>>>
>>>>> One could, temporarily, mistake the added combination for a full
>>>>> carrier
>>>>> with independent sidebands, however.
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>> (For sines it is
>>>>>> sin(a) * sin(b) = 0.5 * (cos[a-b]-cos[a+b])
>>>>>> = 0.5 * (sin[a-b+90degrees] - sin[a+b+90degrees])
>>>>>> = 0.5 * (sin[a-b+90degrees] + sin[a+b-90degrees])
>>>>>> )
>>>>>>
>>>>>> --
>>>>>> rb
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>> When AM is correctly accomplished (a single voiceband signal is
>>> modulated
>>
>> The questions I posed were not about AM. The
>> subject could have been viewed as DSB but that
>> wasn't the specific intent either.
>
> You should take some time to more carefully frame your questions.
>
> Do you understand that a DSB signal *is* AM?

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

>
> Post your intention; it might help.
>
>>
>>> onto a carrier via a non-linear process), at an envelope detector the
>>> two
>>> sidebands will be additive. But if you independe ntly place a carrier
>>> at
>>> frequency ( c ), another carrier at ( c-1 khz) and another carrier at
>>> (c+
>>> 1
>>> kHz), the composite can look like an AM signal, but it is not, and only
>>> by
>>> the most extreme luck will the sidebands be additive at the detector.
>>> They
>>> would probably cycle between additive and subtractive since they have no
>>> real relationship and were not the result of amplitude modulation.
>>>
>>
>>
>

"Rich Grise" <rich@example.net> wrote in message
news:pan.2007.07.05.23.42.45.964093@example.net...
> On Tue, 03 Jul 2007 22:42:20 -0700, isw wrote:
>
>> After you get done talking about modulation and sidebands, somebody
>> might want to take a stab at explaining why, if you tune a receiver to
>> the second harmonic (or any other harmonic) of a modulated carrier (AM
>> or FM; makes no difference), the audio comes out sounding exactly as it
>> does if you tune to the fundamental? That is, while the second harmonic
>> of the carrier is twice the frequency of the fundamental, the sidebands
>> of the second harmonic are *not* located at twice the frequencies of the
>> sidebands of the fundamental, but rather precisely as far from the
>> second harmonic of the carrier as they are from the fundamental.
>
> Have you ever actually observed this effect?
>
> Thanks,
> Rich
>

I have.
I tuned to the third harmonic of a strong local
AM broadcast station. There it was. Quite
a surprise. It is a bit distorted but intelligible.
Another odd thing is that it comes and goes
somewhat abruptly.

In article <468fe7df$0$16560$4c368faf@roadrunner.com>,
"Ron Baker, Pluralitas!" <this@aint.me> wrote:


--snippety-snip--

> >> You said you are a physicist/engineer.
> >> What does "linear" mean?
> >
> > Let's not get too far off the subject here. We were discussing whether
> > the "tuning beat" that you use to tune a musical instrument involved a
> > nonlinear process (ie. "modulation").
>
> Then linearity is at the core of the matter.
> What does "linear" (or "nonlinear") mean to you?

OK, if you insist -- *in this case* it means "linear enough to not
produce IM products of significant amplitude".

> > I said that it does not, and that
> > it could be detected by instrumentation which was proveably linear (i.e.
> > not "perfectly" linear, because that's not required, but certainly
> > linear enough to discount the requirement for "modulation").
>
> No nonlinearity is necessary in order to hear
> a beat?
> Where does the beat come from?

As the phase of the two nearly equal waves move past each other, there
is simple vector summation which varies the amplitude.

Consider two sine waves of precisely the same frequency, where one of
them is adjustable in phase -- use a goniometer, for instance. Use a set
of resistors to sum the two signals, and observe the summing point with
a 'scope or a loudspeaker. By altering the phase of one source, you can
get any amplitude you want from zero up to twice the amplitude of either
one.

Now just twiddle that phase knob around and around as fast as you can.

You've just slightly altered the instantaneous frequency of one of the
generators (but only while you twiddle), and accomplished pretty much
the same effect as listening to the beat between two guitar strings at
nearly zero frequency offset. With no nonlinear processes in sight.

Isaac

On 7/7/07 9:17 PM, in article 469064fd$0$16540$4c368faf@roadrunner.com, "Ron
Baker, Pluralitas!" <this@aint.me> wrote:

>
> "Don Bowey" <dbowey@comcast.net> wrote in message
> news:C2B403C2.6DC94%dbowey@comcast.net...
>> On 7/4/07 8:42 PM, in article 468c6838$0$4664$4c368faf@roadrunner.com,
>> "Ron
>> Baker, Pluralitas!" <this@aint.me> wrote:
>>
>>>
>>> "Don Bowey" <dbowey@comcast.net> wrote in message
>>> news:C2B16AE5.6D5BC%dbowey@comcast.net...
>>>> On 7/4/07 10:16 AM, in article 468bd5ad$0$16531$4c368faf@roadrunner.com,
>>>> "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>>>>
>>>>>
>>>>> "Don Bowey" <dbowey@comcast.net> wrote in message
>>>>> news:C2B1129D.6D573%dbowey@comcast.net...
>>>>>> On 7/4/07 7:52 AM, in article
>>>>>> 468bb3c0$0$24780$4c368faf@roadrunner.com,
>>>>>> "Ron
>>>>>> Baker, Pluralitas!" <this@aint.me> wrote:
>>>>>
>>>>> <snip>
>>>>>
>>>>>>>
>>>>>>> cos(a) * cos(b) = 0.5 * (cos[a+b] + cos[a-b])
>>>>>>>
>>>>>>> Basically: multiplying two sine waves is
>>>>>>> the same as adding the (half amplitude)
>>>>>>> sum and difference frequencies.
>>>>>>
>>>>>> No, they aren't the same at all, they only appear to be the same
>>>>>> before
>>>>>> they are examined. The two sidebands will not have the correct phase
>>>>>> relationship.
>>>>>
>>>>> What do you mean? What is the "correct"
>>>>> relationship?
>>>>>
>>>>>>
>>>>>> One could, temporarily, mistake the added combination for a full
>>>>>> carrier
>>>>>> with independent sidebands, however.
>>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> (For sines it is
>>>>>>> sin(a) * sin(b) = 0.5 * (cos[a-b]-cos[a+b])
>>>>>>> = 0.5 * (sin[a-b+90degrees] - sin[a+b+90degrees])
>>>>>>> = 0.5 * (sin[a-b+90degrees] + sin[a+b-90degrees])
>>>>>>> )
>>>>>>>
>>>>>>> --
>>>>>>> rb
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>> When AM is correctly accomplished (a single voiceband signal is
>>>> modulated
>>>
>>> The questions I posed were not about AM. The
>>> subject could have been viewed as DSB but that
>>> wasn't the specific intent either.
>>
>> You should take some time to more carefully frame your questions.
>>
>> Do you understand that a DSB signal *is* AM?
>
> So all the AM broadcasters are wasting money by
> generating a carrier?


You are an ignorant, useless troll, and not worth my time


>
>>
>> Post your intention; it might help.
>>
>>>
>>>> onto a carrier via a non-linear process), at an envelope detector the
>>>> two
>>>> sidebands will be additive. But if you independe ntly place a carrier
>>>> at
>>>> frequency ( c ), another carrier at ( c-1 khz) and another carrier at
>>>> (c+
>>>> 1
>>>> kHz), the composite can look like an AM signal, but it is not, and only
>>>> by
>>>> the most extreme luck will the sidebands be additive at the detector.
>>>> They
>>>> would probably cycle between additive and subtractive since they have no
>>>> real relationship and were not the result of amplitude modulation.
>>>>
>>>
>>>
>>
>
>

"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
news:469064fd$0$16540$4c368faf@roadrunner.com...
>> 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.

Ron Baker, Pluralitas! wrote:

> Could it be that the human auditory system is not
> linear?


No. Humans had to evolve to incorporate a non linear response to sound
when the electronics manufacturers started supplying ONLY non linear
potentiometers for audio equipment use.

This mutation, which is now the norm, was completely unknown before the
start of the twentieth century.

We, here at Densa Labs, call it Darwinian Decibelism



mike

On Jul 7, 9:56 pm, "Dana" <raff...@yahoo.com> wrote:
> "Ron Baker, Pluralitas!" <t...@aint.me> wrote in messagenews:469064fd$0$16540$4c368faf@roadrunner.c om...
>
> >> 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.

Somewhere between the Original Post #1
and the 236 Replies to date. ~ RHF

"Bob Myers" <nospamplease@address.invalid> hath wroth:

>"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
>news:468fe7df$0$16560$4c368faf@roadrunner.com.. .

>> 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.

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

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

"isw" <isw@witzend.com> wrote in message
news:isw-664E24.21491207072007@newsgroups.comcast.net...
> In article <468fe7df$0$16560$4c368faf@roadrunner.com>,
> "Ron Baker, Pluralitas!" <this@aint.me> wrote:
>
>
> --snippety-snip--
>
>> >> You said you are a physicist/engineer.
>> >> What does "linear" mean?
>> >
>> > Let's not get too far off the subject here. We were discussing whether
>> > the "tuning beat" that you use to tune a musical instrument involved a
>> > nonlinear process (ie. "modulation").
>>
>> Then linearity is at the core of the matter.
>> What does "linear" (or "nonlinear") mean to you?
>
> OK, if you insist -- *in this case* it means "linear enough to not
> produce IM products of significant amplitude".

Good enough.
Then spectrum analyzers and the human auditory
system are not linear.
Stay with me here.

>
>> > I said that it does not, and that
>> > it could be detected by instrumentation which was proveably linear
>> > (i.e.
>> > not "perfectly" linear, because that's not required, but certainly
>> > linear enough to discount the requirement for "modulation").
>>
>> No nonlinearity is necessary in order to hear
>> a beat?
>> Where does the beat come from?
>
> As the phase of the two nearly equal waves move past each other, there
> is simple vector summation which varies the amplitude.
>
> Consider two sine waves of precisely the same frequency, where one of
> them is adjustable in phase -- use a goniometer, for instance. Use a set
> of resistors to sum the two signals, and observe the summing point with
> a 'scope or a loudspeaker. By altering the phase of one source, you can
> get any amplitude you want from zero up to twice the amplitude of either
> one.
>
> Now just twiddle that phase knob around and around as fast as you can.
>
> You've just slightly altered the instantaneous frequency of one of the
> generators (but only while you twiddle), and accomplished pretty much
> the same effect as listening to the beat between two guitar strings at
> nearly zero frequency offset. With no nonlinear processes in sight.
>
> Isaac

You put some effort into that. I give you
credit for that.

The socratic thing isn't working, so here
you go.

Is an envelope detector linear? The answer is no.
But how can that be? If you put in a sine wave of
amplitude A you get A volts out (assuming its gain is 1).
If you put in a sine wave of amplitude 2A and you
get 2A volts out. Linear, right?
Now you put in a sine wave of amplitude A at
455 kHz plus a sine wave of amplitude A at
456 kHz. (Consider the envelope detector
of a typical AM radio here.) What do you get out? A
sine wave of amplitude A/2 at 1 kHz. Intermodulation.
An envelope detector is not linear. No envelope/
amplitude detector is linear.

The typical envelope detector is a diode rectifier
followed by a lowpass filter.
The diode rectifier is obviously nonlinear and
gives you all sorts of intermoduation. With a
single sine wave input you get a DC term and
various harmonics of the sine wave. The lowpass
filter filters out all the harmonics and leaves
the DC.
If you put in two sine waves (assuming their
frequencies are above the cutoff of the subsequent
lowpass and their difference is within the
lowpass) again the diode nonlinearity results
in intermodulation. You get a DC component,
the difference frequency, the sum, and various
higher frequencies. The filter leaves only the
difference frequency and the DC. In an AM
receiver the DC is subsequently blocked too.

Do you see how this applies to spectrum analyzers
and the human auditory system?

In article <46910fe5$0$8925$4c368faf@roadrunner.com>,
"Ron Baker, Pluralitas!" <this@aint.me> wrote:

> "isw" <isw@witzend.com> wrote in message
> news:isw-664E24.21491207072007@newsgroups.comcast.net...
> > In article <468fe7df$0$16560$4c368faf@roadrunner.com>,
> > "Ron Baker, Pluralitas!" <this@aint.me> wrote:
> >
> >
> > --snippety-snip--
> >
> >> >> You said you are a physicist/engineer.
> >> >> What does "linear" mean?
> >> >
> >> > Let's not get too far off the subject here. We were discussing whether
> >> > the "tuning beat" that you use to tune a musical instrument involved a
> >> > nonlinear process (ie. "modulation").
> >>
> >> Then linearity is at the core of the matter.
> >> What does "linear" (or "nonlinear") mean to you?
> >
> > OK, if you insist -- *in this case* it means "linear enough to not
> > produce IM products of significant amplitude".
>
> Good enough.
> Then spectrum analyzers and the human auditory
> system are not linear.
> Stay with me here.
>
> >
> >> > I said that it does not, and that
> >> > it could be detected by instrumentation which was proveably linear
> >> > (i.e.
> >> > not "perfectly" linear, because that's not required, but certainly
> >> > linear enough to discount the requirement for "modulation").
> >>
> >> No nonlinearity is necessary in order to hear
> >> a beat?
> >> Where does the beat come from?
> >
> > As the phase of the two nearly equal waves move past each other, there
> > is simple vector summation which varies the amplitude.
> >
> > Consider two sine waves of precisely the same frequency, where one of
> > them is adjustable in phase -- use a goniometer, for instance. Use a set
> > of resistors to sum the two signals, and observe the summing point with
> > a 'scope or a loudspeaker. By altering the phase of one source, you can
> > get any amplitude you want from zero up to twice the amplitude of either
> > one.
> >
> > Now just twiddle that phase knob around and around as fast as you can.
> >
> > You've just slightly altered the instantaneous frequency of one of the
> > generators (but only while you twiddle), and accomplished pretty much
> > the same effect as listening to the beat between two guitar strings at
> > nearly zero frequency offset. With no nonlinear processes in sight.
> >
> > Isaac
>
> You put some effort into that. I give you
> credit for that.
>
> The socratic thing isn't working, so here
> you go.

I would appreciate it if you would take the time to list *in detail* any
errors in what I wrote. If it "isn't working", I need to know why,
because I don't like to be confused about things.

> Is an envelope detector linear? The answer is no.

That's correct, and I'm well aware of it, but so what?

--dissertation on how an envelope detector works snipped--

> Do you see how this applies to spectrum analyzers
> and the human auditory system?

Sure. But

1) It is possible -- if not practical -- to build a "detectorless" (in
the nonlinear process sense) spectrum analyzer, and

2) None of it is even remotely significant to the subject at hand.

Here it is again: the "beat" one hears when tuning a guitar or other
instrument does *not* require any nonlinear process for its production.
Period.

Isaac

In article <1qu09392icr130gp0c25lcnftjm6ifg96t@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

> "Bob Myers" <nospamplease@address.invalid> hath wroth:
>
> >"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
> >news:468fe7df$0$16560$4c368faf@roadrunner.com.. .
>
> >> 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