Quadruple Sideband?
vimx
channel. It seems to me as if you could put four voices on a single channel.
That is , USB , USB quadrature , LSB , and LSB quadrature. And it seems as if
you could build a special receiver to select which one.
It also seems to me that it might be possible to squeeze a third phase into
each sideband (like the color signal in a TV does with R,G,B). And also you
might be able to put an AM signal and Quadrature AM signal on top of that.
Since the AM appears in both sidebands, you could extract it kinda like how
stereo L and R are separated in FM radio. A matrix or something. So now we
have 8 stations on the same frequency and I think it's possible to separate
them so that you only hear one. (on an ordinary receiver you'd hear them all).
Is this correct? Maybe I havent thought of all the ways you can squeeze them
together. What then is the limit?
If a lot of people are talking in a room you may be able to listen to one
particular person and ignore the rest. At some point, there are too many and
then you can't. Does this have something to do with it? I think Phase has
something to do with where it sounds like someone is coming from. Perhaps its
possible to make a microphone/device which would let you hear a single person
and not all the others in the room. It probabley would need only two channels
(ie. two sidebands or phases). And in that case, there is an infinite number
of radio channels,Right?
Richard Karlquist
> I was thinking about how many distinct voices might be possible in a 5 KHz
>channel. It seems to me as if you could put four voices on a single channel.
>That is , USB , USB quadrature , LSB , and LSB quadrature. And it seems as if
>you could build a special receiver to select which one.
No. There are only two "dimensions" associated with a carrier.
You can do USB and LSB independently. You can do DSB in phase and
DSB in quadrature. You can do AM and PM independently. But if you try
to do more than 2 signals, they will interfere. For example, USB "quadrature"
is meaningless because carrier phase is not important in SSB.
In fact you don't even need to get the *frequency* of the carrier
right on for SSB.
To get more than 2 independent signals to occupy the same channel, you
would have to go to digital techniques.
Rick N6RK
rka...@scd.hp.com
Fred McKenzie
Karlquist) wrote:
> To get more than 2 independent signals to occupy the same channel, you
> would have to go to digital techniques.
Rick-
It seems to me that in the case of USB plus LSB, you are actually using
two separate communications channels. In other words, you define a double
sideband channel bandwidth, and occupy it with two single sideband
stations. Each station generates very little energy in the bandwidth
occupied by the other station.
However, with the other schemes, you may transmit two channels of
information, but not from two separate, independent sites. From separate
sites, there would be no coherence between the two information channels,
and interference would result. Therefore, only one station could
realistically occupy the radio channel, even though it could transmit more
than one information channel.
Along those lines, sub-carriers could be used to add additional
information. Of course, this would increase bandwidth. The digital
techniques you mentioned, would also increase bandwidth, although several
stations could occupy a channel if they were either synchronized or using
spread-spectrum techniques.
I think the "bottom line" is that only the USB plus LSB scheme actually
permits more independent conversations in a given bandwidth. But, this is
no different than using all the same sideband, and spacing at half the
distance along the band. Quite often, I hear SSB conversations at 2 KHz
intervals, which usually works OK. However, you will also hear stations
only a few hundred Hz apart on crowded bands like 20 Meters. Although it
isn't pleasant, you can usually understand what is being said, using your
brain as a "filter"!
73, Fred, K4DII
Richard Karlquist
Fred McKenzie <fred-m...@ksc.nasa.gov> wrote:
>
>Rick-
>
>It seems to me that in the case of USB plus LSB, you are actually using
>two separate communications channels. In other words, you define a double
>sideband channel bandwidth, and occupy it with two single sideband
>stations. Each station generates very little energy in the bandwidth
>occupied by the other station.
>
>However, with the other schemes, you may transmit two channels of
>information, but not from two separate, independent sites. From separate
>sites, there would be no coherence between the two information channels,
You're absolutely right, Fred. Thanks for clarifying that.
Rick
Al Davis
> I was thinking about how many distinct voices might be possible in a 5 KHz
>channel. It seems to me as if you could put four voices on a single channel.
>That is , USB , USB quadrature , LSB , and LSB quadrature. And it seems as if
>you could build a special receiver to select which one.
> It also seems to me that it might be possible to squeeze a third phase into
>each sideband (like the color signal in a TV does with R,G,B). And also you
>might be able to put an AM signal and Quadrature AM signal on top of that.
>Since the AM appears in both sidebands, you could extract it kinda like how
>stereo L and R are separated in FM radio. A matrix or something. So now we
>have 8 stations on the same frequency and I think it's possible to separate
>them so that you only hear one. (on an ordinary receiver you'd hear them all).
>Is this correct? Maybe I havent thought of all the ways you can squeeze them
>together. What then is the limit?
TV color is done by a combination of amplitude and phase modulation.
AM carries the saturation. PM carries the hue. There are two
channels there.
FM stereo is time division multiplexed.
Single sideband can be thought of as simultaneous AM (sidebands in
phase) and FM (sidebands out of phase). If you have a phasing rig,
drive one modulator and unbalance it, you get AM. Drive one modulator
and unbalance the other you get FM.
The technique you propose suggests the old 4-channel audio techniques
like SQ and QS. You get a big 3 db channel separation.
David Feldman
>intervals, which usually works OK. However, you will also hear stations
Actually _more_ efficient than ISB (USB+LSB) because the lower freq cutoff
of most SSB transmitters is 300 Hz, leading to 600 Hz unoccupied on ISB;
if boxcar (sharp cutoff) filters were used everywhere, the upper 300 Hz
of bandwidth of one SSB signal could overlap the unoccupied bottom 300 Hz
of the next.
Dave
Bruce Toback
>FM stereo is time division multiplexed.
?? I thought FM stereo was frequency-division multiplexed, with a 38 KHz
subcarrier carrying an L-R signal added to the baseband L+R signal.
-- Bruce KN6MN
Michael J Dower
bto...@netcom.com "Bruce Toback" writes:
Yes, L-R is used to DSB-modulate the 38 kHz sub-carrier. A phase-related 19
kHz pilot tone is added to the signal, as well as L+R, and the resulting
composite signal is used to FM the carrier. The 19 kHz pilot tone is doubled by
the stereo receiver to provide the re-inserted in-phase 38 kHz sub-carrier
needed to detect the L-R component in a product detector. Then, an audio
matrix resolves L and R channels by L = ( (L+R)+(L-R) )/2; and R = ( (L+R)-(L-
R) )/2.
73's de VK2ENG.
--
Michael J Dower
'Quoth the raven, "Never more".' ... Poe
Mark Zenier
They're actually the same thing (minus the pilot tone). If you
alternate the two audio channels so that each side gets 1/2 * 1/38000
second, the ripple between the left and right comes out equivalent to
a DSB modulated 38 kHz signal. Coming up with the necessary low pass
filter that didn't mess it up could be nontrivial.
Mark Zenier mze...@netcom.com mze...@eskimo.com
jasonda...@gmail.com
Here's how it works for AM.
When you modulate 100%, you get one on each side, 200% two on each side.
They act like additional amplitude, like an amplifier.
The more sidebands there are, the louder it will be x1,x2,x3,x4 louder.
ji...@specsol.spam.sux.com
--
Jim Pennino
Michael Black
about something but is making some sort of sense, if ill informed, and the
eight replies that the message got back then.
Yes indeed, this is yet another case of someone replying to an old message
via google, and as is the case virtually every time, the first person
replying has really nothing to add.
Michael VE2BVW
Jim Mueller
--
Jim Mueller wron...@nospam.com
To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.
Channel Jumper
'Michael Black[_2_ Wrote:
> ;803134']On Tue, 26 Mar 2013, ji...@specsol.spam.sux.com wrote:
> -
> jasonda...@gmail.com wrote:-
>
> Here's how it works for AM.
>
> When you modulate 100%, you get one on each side, 200% two on each
> side.
>
> They act like additional amplitude, like an amplifier.
>
> The more sidebands there are, the louder it will be x1,x2,x3,x4
>
> Babbling nonsense.
> -
> You should see the original 1994 thread, where someone speculates
> the
> eight replies that the message got back then.
>
> Yes indeed, this is yet another case of someone replying to an old
> message
>
>
> Michael VE2BVW
inside of any of them ever came close to the confabulations this person
proposes.
You have a carrier - which does nothing except carry the intelligence
and you have a upper and a lower side band - which is the intelligence
that rides upon the carrier. And that is it for AM!
In single side band you suppress one side band which forces the energy
up into the other side band.
When Regency came out with Double Suppressed Side Band, they suppressed
both the carrier and one side band.. The model I had was the Range Gain
II or the Imperial. Either model required another radio that could do
the same thing in order for it to work - else you ended up talking to
yourself.
When the Japanese came into the market with the cheap CB radios, all
that technology was forgotten and the companies that made it were soon
forced to do other things or get out of the business because the days of
quality American Made CB radios came to an end when Cobra came out with
a $39.00 AM CB that did the same thing as the more expensive units -
just didn't have SSB or DSSB...
Television used a mode called Vestigial side band where part of the one
side band was suppressed and the remaining energy was diverted up into
the remaining side band.
If there was a way to double the power, don't you think that someone
would have came up with it long before now?
AM for the most part is dead as far as commercial broadcast goes and the
only people who participates in it on Amateur Radio are the ones with
the old boat anchors who wants to keep their tubes warm, who thinks that
they are doing something when they broadcast with their old equipment.
It usually ends up being a bunch of old lids who talks just to hear
themselves talk, with nothing of no importance to say and just looking
for an audience...
--
Channel Jumper
cnc...@gmail.com
I knew a Fred McKenzie there..
Chuck
K4TZO
Fred McKenzie
Chuck-
Earlier we spoke on the phone. Am sending E-Mail reply.
Fred