Thread View: uk.tech.digital-tv
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Started by Green Xenon [Radium]
Fri, 28 Sep 2007 03:25
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Fri, 28 Sep 2007 03:25
Date: Fri, 28 Sep 2007 03:25
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On Sep 27, 6:13 pm, dpl...@radagast.org (Dave Platt) wrote in http://groups.google.com/group/uk.tech.digital-tv/msg/118b30e3f36c8b05 : > In article <46fc4458$0$16496$4c368...@roadrunner.com>, > Green Xenon [Radium] <gluceg...@excite.com> wrote: > >It�s possible to downshift the frequencies of an audio signal without > >low-pass-filtering or changing the speed at which it is played-back. > >Couldn�t the equivalent be done with the temporal and spatial > >frequencies of a luminance signal? > > Once again, no, not enough to matter. If it was only a matter of 2:1 > or 10:1, you might be able to do it. The one-baud scheme you propose > is off by a factor of 1,000,000,000,000,...,000 to 1 or so (*lots* of > zeros in there). Would 300:1 work? 300 Hz is the minimum frequency used by telephones and ULF [Ultra-Low-Frequency] radios. ULF radio = frequencies at least 300 Hz but no more than 3,000 Hz. > Go do as I said, and google "Shannon Limit". To sum it up: there's a > hard limit on the amount of information that you can send through a > communication channel which has (a) a finite bandwidth, and (2) a > finite signal-to-noise ratio. > > Your goal of trying to pack video-grade information into small gaps in > the MW spectrum goes far beyond the Shannon limit. The ULF is even lower-frequency than MW. If a baud of 20-symbols-per-second but 300 bits-per-symbol is used, can the luminance signal have its temporal and spatial frequencies downshifted sufficiently so that it can be on a ULF-frequency FM carrier? Will this work even if the FM carrier�s center-frequency is 300 Hz? > >Is there any thing that could be done to the QM signal so that the > >resulting FM sidebands won�t be excessive? > > >In an FM carrier, the neutral frequency results when there is no > >modulation signal. The FM carrier changes > >according to the modulator. If > >the modulator voltage it positive, > >the FM carrier�s frequency increases. > >When the modulator voltage becomes negative, the carrier�s frequency > >decreases. On a graph of the modulator signal, > >the x-axis is where the > >voltage is neutral. Above the x-axis, > >the voltage is positive. Below the > >x-axis, the voltage is negative. > >The further from the x-axis the voltage > >goes, the more broad the sidebands will be. > > >To prevent the sidebands from getting too broad, > >the QM signal needs to > >have all to voltages shifted closer to the x-axis. > >This means the device > >receiving the QM signals on the other end > >needs to be more sensitive to > >differences in voltages. > > >Thus it would help if the physical voltage difference between what is > >interpreted as 1 or 0 be much smaller. The smaller the change in > >voltage, the less extreme the resulting FM sidebands. > Your understanding of FM modulation is incomplete, and it is leading > you astray. You're only looking at half of the picture. You need to > go back and hit the books again so that you understand the whole > situation. > > Yes, it's true that the instantaneous carrier deviation depends only > on the amplitude of the modulation signal. However, that's only part > of the picture. Sidebands are created out *beyond* the maximum > carrier deviation frequency... and they are created at frequencies > which are at offset-multiples of the modulating frequency. > > You *cannot* narrow an FM signal down to a width less than the > modulating frequency. If you want to carry (for example) an audio > signal with 20,000 Hz of audio bandwidth, then the modulated FM signal > will always have sidebands out as far as 20,000 Hz on either side of > the nominal carrier frequency. This is true NO MATTER HOW SMALL the > amplitude of the modulating signal, as long as there's any signal at > all. > > If you FM-modulate a carrier with a very low-level 20 kHz tone, you > might be causing only 1 kHz of carrier deviation... but there will > still be sidebands 20 kHz above and below the nominal carrier > frequency. That may seem strange and counterintuitive, but it's how > the math works out, and how measurements confirm it works. So there is no way to decrease how far the sidebands will go?
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Dave Platt
Date: Fri, 28 Sep 2007 05:50
Date: Fri, 28 Sep 2007 05:50
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In article <46fc71d2$0$24285$4c368faf@roadrunner.com>,
Green Xenon [Radium] <glucegen1@excite.com> wrote:
>Would 300:1 work?
Not for video, no.
>The ULF is even lower-frequency than MW. If a baud of
>20-symbols-per-second but 300 bits-per-symbol is used, can the luminance
>signal have its temporal and spatial frequencies downshifted
>sufficiently so that it can be on a ULF-frequency FM carrier? Will this
>work even if the FM carrier�s center-frequency is 300 Hz?
No. No. And, no. You cannot possibly do this... for several reasons.
For one thing, trying to convey 300 bits of information per symbol is
still grossly optimistic. If you take a look at real-world modulation
systems (QAM64 and so forth) you'll find that they send much less
information per symbol... I don't have the best numbers available off
of the top of my head, but I'd be surprised if there's a system in
practical use which tries to send more than 16 bits per symbol. The
amount of noise on real-world communcation channels makes it
impractical-to-impossible to go much beyond that... and you are
proposing something *far* beyond that. Trust me - the laws of physics
in this universe won't permit you to do it.
For another thing, even if you *could* pack that much information into
a symbol, you'd still be capable of sending only 6000 bits per second.
That's far too little for anything resembling real video at real
resolutions... you couldn't even send one frame per second at that
rate.
For a third thing, the frequency content of a video luminance signal
starts just above DC, and goes up from there (to several MHz with
standard NTSC video). There really isn't any room for you to shift
the frequencies downwards by a useful amount... if you try, you end up
trying to shift real information down past DC. Either you lose it (if
you filter before shifting) or you *try* to shift it down past DC into
negative frequencies, and it aliases right back up into your passband
and distorts the rest of the signal.
To sum it up - what you're trying to do is fundamentally impossible.
It doesn't matter how you shift the luminance signal's frequencies
around. It doesn't matter how you modulate it. It doesn't matter
what tricks you play. You just don't have enough bandwidth available.
"You can't fool Mother Nature."
>So there is no way to decrease how far the sidebands will go?
With FM? Nope, not in the way you're hoping. Modulate a carrier Fc
with a frequency Fm, and the first sidebands will be at Fc+Fm and
Fc-Fm, just as would be true with AM. That's the narrowest you can
get.
--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Steven
Date: Fri, 28 Sep 2007 10:31
Date: Fri, 28 Sep 2007 10:31
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Everybody has Asberger's (sic) Syndrome online.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Richard Crowley
Date: Fri, 28 Sep 2007 14:59
Date: Fri, 28 Sep 2007 14:59
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"Dave Platt" wrote ... > No. No. And, no. You cannot possibly do this... for several reasons. > > For one thing, trying to convey 300 bits of information per symbol is > still grossly optimistic. If you take a look at real-world modulation > systems (QAM64 and so forth) you'll find that they send much less > information per symbol... I don't have the best numbers available off > of the top of my head, but I'd be surprised if there's a system in > practical use which tries to send more than 16 bits per symbol. The > amount of noise on real-world communcation channels makes it > impractical-to-impossible to go much beyond that... and you are > proposing something *far* beyond that. Trust me - the laws of physics > in this universe won't permit you to do it. Perhaps "Radium" should ask his questions over there in that other universe where *his* laws of physics apply.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Sjouke Burry
Date: Fri, 28 Sep 2007 21:54
Date: Fri, 28 Sep 2007 21:54
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Dave Platt wrote: > In article <46fc71d2$0$24285$4c368faf@roadrunner.com>, > Green Xenon [Radium] <glucegen1@excite.com> wrote: > >> Would 300:1 work? > > Not for video, no. > >> The ULF is even lower-frequency than MW. If a baud of >> 20-symbols-per-second but 300 bits-per-symbol is used, can the luminance >> signal have its temporal and spatial frequencies downshifted >> sufficiently so that it can be on a ULF-frequency FM carrier? Will this >> work even if the FM carrier�s center-frequency is 300 Hz? > > No. No. And, no. You cannot possibly do this... for several reasons. > Yes he can. As a known troll on many newsgroup he can do anything. Eve hide under a bridge.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Sat, 27 Oct 2007 08:45
Date: Sat, 27 Oct 2007 08:45
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Dave Platt wrote: > In article <46fc71d2$0$24285$4c368faf@roadrunner.com>, > Green Xenon [Radium] <glucegen1@excite.com> wrote: >>So there is no way to decrease how far the sidebands will go? > With FM? Nope, not in the way you're hoping. Modulate a carrier Fc > with a frequency Fm, and the first sidebands will be at Fc+Fm and > Fc-Fm, just as would be true with AM. That's the narrowest you can > get. So a higher-frequency modulation signal will result in more distant sidebands than a lower-frequency modulation signal? E.g. a 10,000 Hz tone will result in sidebands further from the base carrier frequency than a 1,000 Hz signal?
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Roderick Stewart
Date: Sat, 27 Oct 2007 10:28
Date: Sat, 27 Oct 2007 10:28
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In article <4722f832$0$25703$4c368faf@roadrunner.com>, Green Xenon [Radium] wrote: > >>So there is no way to decrease how far the sidebands will go? > > > With FM? �Nope, not in the way you're hoping. �Modulate a carrier Fc > > with a frequency Fm, and the first sidebands will be at Fc+Fm and > > Fc-Fm, just as would be true with AM. �That's the narrowest you can > > get. > > So a higher-frequency modulation signal will result in more distant� > sidebands than a lower-frequency modulation signal? E.g. a 10,000 Hz� > tone will result in sidebands further from the base carrier frequency� > than a 1,000 Hz signal? By George! I think he's got it! Rod.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Brian Gaff
Date: Sat, 27 Oct 2007 14:00
Date: Sat, 27 Oct 2007 14:00
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Why do you think they used such a wide band fm for radio? Also there is often pre emphasis to look at as well. Brian -- Brian Gaff - briang1@blueyonder.co.uk Note:- In order to reduce spam, any email without 'Brian Gaff' in the display name may be lost. Blind user, so no pictures please! "Roderick Stewart" <escapetime@removethisbit.beeb.net> wrote in message news:VA.0000018f.006be928@removethisbit.beeb.net... > In article <4722f832$0$25703$4c368faf@roadrunner.com>, Green Xenon > [Radium] wrote: >> >>So there is no way to decrease how far the sidebands will go? >> >> > With FM? Nope, not in the way you're hoping. Modulate a carrier Fc >> > with a frequency Fm, and the first sidebands will be at Fc+Fm and >> > Fc-Fm, just as would be true with AM. That's the narrowest you can >> > get. >> >> So a higher-frequency modulation signal will result in more distant >> sidebands than a lower-frequency modulation signal? E.g. a 10,000 Hz >> tone will result in sidebands further from the base carrier frequency >> than a 1,000 Hz signal? > > By George! I think he's got it! > > Rod. >
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: John Evans
Date: Sat, 27 Oct 2007 17:06
Date: Sat, 27 Oct 2007 17:06
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On Sat, 27 Oct 2007 01:45:25 -0700, "Green Xenon [Radium]" <glucegen1@excite.com> wrote: >Dave Platt wrote: > >> In article <46fc71d2$0$24285$4c368faf@roadrunner.com>, >> Green Xenon [Radium] <glucegen1@excite.com> wrote: > > >>>So there is no way to decrease how far the sidebands will go? > > >> With FM? Nope, not in the way you're hoping. Modulate a carrier Fc >> with a frequency Fm, and the first sidebands will be at Fc+Fm and >> Fc-Fm, just as would be true with AM. That's the narrowest you can >> get. Oh dear - what about the deviation? The rule of thumb bandwidth required for FM (Carson's Rule) says the bandwidth is given by 2x(peak deviation x highest modulating frquency). So a system with a maximum modulating sinusoidal frequency of 15khz using a deviation of 75khz needs 180khz bandwidth minimum. Note a pulse would require a far greater bandwidth. http://www.fmsystems-inc.com/eng_fm.htm http://en.wikipedia.org/wiki/Frequency_modulation gives
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Sjouke Burry
Date: Sat, 27 Oct 2007 18:35
Date: Sat, 27 Oct 2007 18:35
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Roderick Stewart wrote: > In article <4722f832$0$25703$4c368faf@roadrunner.com>, Green Xenon > [Radium] wrote: >>>> So there is no way to decrease how far the sidebands will go? >>> With FM? Nope, not in the way you're hoping. Modulate a carrier Fc >>> with a frequency Fm, and the first sidebands will be at Fc+Fm and >>> Fc-Fm, just as would be true with AM. That's the narrowest you can >>> get. >> So a higher-frequency modulation signal will result in more distant >> sidebands than a lower-frequency modulation signal? E.g. a 10,000 Hz >> tone will result in sidebands further from the base carrier frequency >> than a 1,000 Hz signal? > > By George! I think he's got it! > > Rod. > Wait, dont count your blessings yet :) The troll may find yet another geeky side to ponder.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Sun, 28 Oct 2007 01:06
Date: Sun, 28 Oct 2007 01:06
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Paul Martin wrote: > In article <ujr6i3dolk1qjon2ij5tta8aip26tff9qa@4ax.com>, > John Evans wrote: > > >>Oh dear - what about the deviation? > > >>The rule of thumb bandwidth required for FM (Carson's Rule) says the >>bandwidth is given by > > >>2x(peak deviation x highest modulating frquency). What is peak deviation measured in? Hz? > >>So a system with a maximum modulating sinusoidal frequency of 15khz >>using a deviation of 75khz needs 180khz bandwidth minimum. > > >>Note a pulse would require a far greater bandwidth. Require a far greater bandwidth compared to what? A sine wave of the same frequency and amplitude? > > Depends on the type of pulse. A wavelet might be about the same. > Are you talking about the pulses [bauds] of QAM signals? Quotes from http://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://www.physics.udel.edu/wwwusers/watson/student_projects/scen167/thosguys/index.html : "The carrier signal is characterized by the number of signal intervals, or pulses, that are transmitted per second. Each pulse is called a baud."
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Tue, 30 Oct 2007 01:13
Date: Tue, 30 Oct 2007 01:13
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Green Xenon [Radium] wrote: > Paul Martin wrote: > >> In article <ujr6i3dolk1qjon2ij5tta8aip26tff9qa@4ax.com>, >> John Evans wrote: >> >> >>> Oh dear - what about the deviation? >> >> >> >>> The rule of thumb bandwidth required for FM (Carson's Rule) says the >>> bandwidth is given by >> >> >> >>> 2x(peak deviation x highest modulating frquency). > > > What is peak deviation measured in? Hz? > >> >>> So a system with a maximum modulating sinusoidal frequency of 15khz >>> using a deviation of 75khz needs 180khz bandwidth minimum. >> >> >> > > >>> Note a pulse would require a far greater bandwidth. > > > Require a far greater bandwidth compared to what? A sine wave of the > same frequency and amplitude? > >> >> Depends on the type of pulse. A wavelet might be about the same. >> > > Are you talking about the pulses [bauds] of QAM signals? > > Quotes from > http://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://www.physics.udel.edu/wwwusers/watson/student_projects/scen167/thosguys/index.html > : > > "The carrier signal is characterized by the number of signal intervals, > or pulses, that are transmitted per second. Each pulse is called a baud." In the original post of the "Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?" I was describing converting the luminance signal to QAM and then broadcasting the QAM video on a ULF [300 Hz] FM carrier in which the QAM uses 1-symbol-per-second and a sufficient amounts of bits-per-symbol to represent the video. Unfortunately for me, it is not possible to do this.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: spamtrap1888
Date: Tue, 30 Oct 2007 15:41
Date: Tue, 30 Oct 2007 15:41
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On Oct 27, 6:06 pm, "Green Xenon [Radium]" <gluceg...@excite.com> wrote: > Paul Martin wrote: > > Depends on the type of pulse. A wavelet might be about the same. > > Are you talking about the pulses [bauds] of QAM signals? > > Quotes fromhttp://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://w... > : > > "The carrier signal is characterized by the number of signal intervals, > or pulses, that are transmitted per second. Each pulse is called a baud." Wrong. A bawd is an elderly slut. You mean a bit.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Matti Lamprhey
Date: Tue, 30 Oct 2007 16:21
Date: Tue, 30 Oct 2007 16:21
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<spamtrap1888@gmail.com> wrote... > "Green Xenon [Radium]" <gluceg...@excite.com> wrote: >> Paul Martin wrote: > >> > Depends on the type of pulse. A wavelet might be about the same. >> >> Are you talking about the pulses [bauds] of QAM signals? >> >> Quotes >> fromhttp://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://w... >> : >> >> "The carrier signal is characterized by the number of signal >> intervals, >> or pulses, that are transmitted per second. Each pulse is called a >> baud." > > Wrong. A bawd is an elderly slut. You mean a bit. Wrong. The baud is a measure of signalling changes per second. Each signalling change can involve multiple bits of data. Therefore bits-per-sec is not equivalent to baud rate (although in practice it used to be in primitive modems). Matti
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: spamtrap1888
Date: Tue, 30 Oct 2007 18:42
Date: Tue, 30 Oct 2007 18:42
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On Oct 30, 9:21 am, "Matti Lamprhey" <ma...@official-totally- reversed.com> wrote: > <spamtrap1...@gmail.com> wrote... > > "Green Xenon [Radium]" <gluceg...@excite.com> wrote: > > >> Quotes > >> fromhttp://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://w... > >> : > > >> "The carrier signal is characterized by the number of signal > >> intervals, > >> or pulses, that are transmitted per second. Each pulse is called a > >> baud." > > > Wrong. A bawd is an elderly slut. You mean a bit. > > Wrong. The baud is a measure of signalling changes per second. Each > signalling change can involve multiple bits of data. Therefore > bits-per-sec is not equivalent to baud rate (although in practice it > used to be in primitive modems). > So, a baud is really an inverse second.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Matti Lamprhey
Date: Tue, 30 Oct 2007 19:18
Date: Tue, 30 Oct 2007 19:18
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<spamtrap1888@gmail.com> wrote... > "Matti Lamprhey" <ma...@official-totally-reversed.com> wrote: >> <spamtrap1...@gmail.com> wrote... >> > "Green Xenon [Radium]" <gluceg...@excite.com> wrote: > >> >> >> Quotes >> >> fromhttp://www.howstuffworks.com/framed.htm?parent=modem.htm&url=http://w... >> >> : >> >> >> "The carrier signal is characterized by the number of signal >> >> intervals, >> >> or pulses, that are transmitted per second. Each pulse is called a >> >> baud." >> >> > Wrong. A bawd is an elderly slut. You mean a bit. >> >> Wrong. The baud is a measure of signalling changes per second. Each >> signalling change can involve multiple bits of data. Therefore >> bits-per-sec is not equivalent to baud rate (although in practice it >> used to be in primitive modems). >> > > So, a baud is really an inverse second. No - you're thinking of the unit which later went into Van Rental. Matti
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Andy Champ
Date: Tue, 30 Oct 2007 20:42
Date: Tue, 30 Oct 2007 20:42
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spamtrap1888@gmail.com wrote: > > So, a baud is really an inverse second. > On a 1-bit-per-transition line, the baud rate is the bit rate. On a parallel or multi-level transmission medium it is *not*. There a nice article at http://en.wikipedia.org/wiki/Baud Which is much better than the one I just wrote and threw away! Andy
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Tue, 30 Oct 2007 22:31
Date: Tue, 30 Oct 2007 22:31
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Andy Champ wrote: > spamtrap1888@gmail.com wrote: > >> >> So, a baud is really an inverse second. >> > > On a 1-bit-per-transition line, the baud rate is the bit rate. On a > parallel or multi-level transmission medium it is *not*. > > There a nice article at > > http://en.wikipedia.org/wiki/Baud > > Which is much better than the one I just wrote and threw away! > > Andy I'd like my QAM video signal to be at least 1-billion-bits-per-symbol but no more than 1-symbol-per-second. I then want to transmit this video signal on an ULF FM radio signal whose carrier wave is only 300 Hz. Lord please make this physically-possible. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. God please. <praying until death from exhaustion>
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Roderick Stewart
Date: Wed, 31 Oct 2007 07:15
Date: Wed, 31 Oct 2007 07:15
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In article <4727a189$0$19640$4c368faf@roadrunner.com>, Green Xenon [Radium] wrote: > I'd like my QAM video signal to be at least 1-billion-bits-per-symbol� > but no more than 1-symbol-per-second. I then want to transmit this video� > signal on an ULF FM radio signal whose carrier wave is only 300 Hz. > > Lord please make this physically-possible. God please. God please. God� [snip] > please. God please. God please. God please. God please. God please. > > <praying until death from exhaustion> I don't think he's listening. What's possible is possible and what isn't isn't, and that's that. Rod.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Wed, 31 Oct 2007 20:53
Date: Wed, 31 Oct 2007 20:53
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Roderick Stewart wrote: > In article <4727a189$0$19640$4c368faf@roadrunner.com>, Green Xenon [Radium] > wrote: > >>I'd like my QAM video signal to be at least 1-billion-bits-per-symbol >>but no more than 1-symbol-per-second. I then want to transmit this video >>signal on an ULF FM radio signal whose carrier wave is only 300 Hz. >> >>Lord please make this physically-possible. God please. God please. God > > [snip] > >>please. God please. God please. God please. God please. God please. >> >><praying until death from exhaustion> > > > I don't think he's listening. What's possible is possible and what isn't > isn't, and that's that. Dayum! Just when I was thinking I could change everything by requesting the Lord to do so! My euphoria just become dysphoria! CRRRRRRRRRRRRRRRRRRRRAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAASSSSSSSSSSSSSSSSSSSSSSSHHHHHHHHHHHHHHHHHHH!
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: spamtrap1888
Date: Wed, 31 Oct 2007 21:01
Date: Wed, 31 Oct 2007 21:01
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On Oct 30, 1:42 pm, Andy Champ <no....@nospam.com> wrote: > spamtrap1...@gmail.com wrote: > > > So, a baud is really an inverse second. > > On a 1-bit-per-transition line, the baud rate is the bit rate. On a > parallel or multi-level transmission medium it is *not*. > > There a nice article at > > http://en.wikipedia.org/wiki/Baud > > Which is much better than the one I just wrote and threw away! A baud used to be a bit time per second (per the historic referenced article in wiki) and now no longer is. Fine. But baud is still a rate: symbols per second; whereas a pulse (from "howstuffworks") is not a rate and thus cannot be a baud.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Bob Myers
Date: Thu, 01 Nov 2007 00:06
Date: Thu, 01 Nov 2007 00:06
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"Green Xenon [Radium]" <glucegen1@excite.com> wrote in message news:4727a189$0$19640$4c368faf@roadrunner.com... > I'd like my QAM video signal to be at least 1-billion-bits-per-symbol but > no more than 1-symbol-per-second. I then want to transmit this video > signal on an ULF FM radio signal whose carrier wave is only 300 Hz. I realize you're again just either trolling or so astoundingly ignorant of the field that it's amazing you're walking around without a keeper, but...why? What possible advantage would such a system have, if it were possible in the first place (which it isn't, not by a rather large number of orders of magnitude)? And what in the hell does "QAM video signal" on an "FM radio signal" mean in the first place? Bob M.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Bob Myers
Date: Thu, 01 Nov 2007 00:07
Date: Thu, 01 Nov 2007 00:07
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<spamtrap1888@gmail.com> wrote in message news:1193864474.235536.151000@i38g2000prf.googlegroups.com... > A baud used to be a bit time per second (per the historic referenced > article in wiki) Trust ye not in Wiki. "Baud rate" NEVER meant the same as "bit rate" - the two just happened to be the same number in early 1 bit/symbol systems. Bob M,
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Thu, 01 Nov 2007 06:08
Date: Thu, 01 Nov 2007 06:08
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Bob Myers wrote: > "Green Xenon [Radium]" <glucegen1@excite.com> wrote in message > news:4727a189$0$19640$4c368faf@roadrunner.com... > > >>I'd like my QAM video signal to be at least 1-billion-bits-per-symbol but >>no more than 1-symbol-per-second. I then want to transmit this video >>signal on an ULF FM radio signal whose carrier wave is only 300 Hz. > > > I realize you're again just either trolling or so astoundingly ignorant of > the field that it's amazing you're walking around without a keeper, > but...why? > > What possible advantage would such a system have, if it were possible > in the first place (which it isn't, not by a rather large number of orders > of magnitude)? Okay I got a bit carried away here. Sorry. 1-billion-bits-per-symbol is equivalent allows for 2^1,000,000,000 voltages. This is not possible. Just an imagination. Please forgive me and forget about it. Anyways, the QAM should be given the highest practical bit-resolution. 1-symbol-per-second should be the baud. The following is interesting but only theoretically-possible. Not gonna happen with today's technology: The minimum voltage should be set to 1.6e-19 volt. This is the voltage of one electron. The maximum voltage should be set to the highest you can get *without* doing any of the following to any extent: 1. Exceeding the dielectric strength of any electronic component 2. Generating temperatures above 70 Fahrenheit in any electronic component 3. Ionizing any electronic component The bit-resolution should be high enough that each "level" is a difference of 1.6e-19 volt from the level above/below. A resolution of 8-bit allows for only 256 different levels -- obviously *way* too low. > > And what in the hell does "QAM video signal" on an "FM radio signal" > mean in the first place? > Again, the following is interesting but only theoretically-possible. Not gonna happen with today's technology: The original Y signal is converted to QAM. This QAM signal is then broadcasted on an FM radio carrier wave whose base frequency is 300 Hz. 300 Hz is the lowest ULF frequency and the lowest frequency used by telephones. http://en.wikipedia.org/wiki/Ultra_low_frequency Prior to converting the Y signal to QAM, the temporal and spatial frequencies [excluding DC -- 0 hertz] are downshifted in real time [sort of like the video-equivalent of the voice-changers used on the phone which can decrease the pitch of your voice in real time without decreasing the speed of your speech]. This frequency downshifting does not involve decreasing the "speeds" of the temporal or spatial components of the Y-signal. All temporal and spatial frequencies other than zero-hertz are shifted closer to zero. This decreases the bandwidth of the Y-signal. No low-pass filtering. No changing the speed of the temporal signal. No changing the size of the spatial signal. Even though the spatial signal does not have "speed" as its component because it is -- by nature -- static, it does have an equivalent which I have a hard time figuring out. Perhaps it�s the size? Decreasing the "speed" might involve increasing the size of the image? I am guessing this is the case. There are many audio softwares that allow downshifting the frequencies of music until they are closer to zero. They can do this without slowing the playback speed or increasing the length of the song. If a frequency is zero Hz, its stays at zero. However, if a frequency is not zero, it is shifted closer to zero. Apparently -- from what I see on the graph my audio software [Adobe Audition 1.5] -- downshifting decreases the amount of cycles per distance and then increases the lengths of the waves. So basically the signal does not take up more space than it did prior to the pitch-shifting. The amount of waves per area decreases but the remaining waves are increased in length, so the distance from where the waves started to where they finish do not decrease -- their lengths increase but their amounts decrease. So overall, the distance from start to finish remains the same. Hence the file�s length does not change. The real-time-video-equivalent of the above is done to decrease the overall frequency [and bandwidth] of the Y-signal prior to converting it to QAM. A sufficient amount of this frequency-downshifting is done to the original Y-signal such that the resulting QAM signal does not cause the FM signal to develop sidebands beyond 301 Hz or 299 Hz -- sideband is only 1 Hz + or - from baseband. Equally important, prior to conversion to QAM, the amplitude levels of the Y-signal are brought closer to the neutral without decreasing the amount of levels -- darker than neutral result is represented by a negative electric current while brighter than neutral is represented as a positive electric current. When the Y-signal is at medium light intensity, the current is neutral [i.e. right on the x-axis of a graph when measured]. Anyways, all of the brightness levels are shifted towards the x-axis so that the resulting QAM signal will not cause the FM radio signal's frequency to deviate beyond 301 Hz or 299 Hz -- peak deviation is only 1 Hz + or - from baseband. In a luminance signal, the medium light intensity is represented by voltages that are neither positive nor negative. If the light intensity increases above the medium brightness, a positive voltage results. If the light intensity falls below medium brightness, a negative voltage results. This is because the Y-signal is represented by AC current. The chroma along with instructions regarding how to reverse-process the Y-signal [so the original Y-signal is retrieved] -- as well as properly linking the chroma with the luma -- is delivered from the transmitting end to the receiving end via optic fibers. That way the equipment receiving the FM video signal can best decode the video back to how it originally looked -- not exactly how it looked but close. One potential disadvantage of this tech is the white flashes on the receiver's screen when there are electrical storms in the atmosphere [such as lightning], or manmade electric disturbances such as florescent lamps and automobile ignitions. Such visual interferences are worse during cloudy/rainy weather -- even if there is no lightning. The reception maybe FM, but the receiver is built to be extremely sensitive to the extremely low power signals emitted from the transmitting end. This FM receiver can coherently receive frequency-modulated 300 Hz electromagnetic signals as weak as 1.3e-24 watts per square meter. This weak signal is equivalent to 1 photon per second per square meter. Turn on a distant xenon-lamp [on the otherside of the world] and boom! The monitor displaying the video signals will start to show some interesting white disruptions -- dancing zig-zag lines, sawtooth waves, etc. That�s how sensitive this receiver is.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Bob Myers
Date: Thu, 01 Nov 2007 08:15
Date: Thu, 01 Nov 2007 08:15
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"Green Xenon [Radium]" <glucegen1@excite.com> wrote in message news:47295e0d$0$11519$4c368faf@roadrunner.com... > Anyways, the QAM should be given the highest practical bit-resolution. > 1-symbol-per-second should be the baud. Fine, but the question remains - what the hell is so important about "1 symbol per second"? Why do you CARE? > The minimum voltage should be set to 1.6e-19 volt. This is the voltage of > one electron. Wrong. Electrons have charge, expressed in coulombs, not voltage. Go figure out the difference, and come back. > > The bit-resolution should be high enough that each "level" is a difference > of 1.6e-19 volt from the level above/below. A resolution of 8-bit allows > for only 256 different levels -- obviously *way* too low. Way too low for WHAT? > The original Y signal is converted to QAM. This QAM signal is then > broadcasted on an FM radio carrier wave whose base frequency is 300 Hz. > 300 Hz is the lowest ULF frequency and the lowest frequency used by > telephones. Restating nonsense doesn't make it less nonsensical. What does "QAM...on an FM radio carrier wave" MEAN on your planet? The rest is just gibberish as well. Bob M.
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Thu, 01 Nov 2007 19:31
Date: Thu, 01 Nov 2007 19:31
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Bob Myers wrote: > "Green Xenon [Radium]" <glucegen1@excite.com> wrote in message > news:47295e0d$0$11519$4c368faf@roadrunner.com... > >>Anyways, the QAM should be given the highest practical bit-resolution. >>1-symbol-per-second should be the baud. > Fine, but the question remains - what the hell is so important > about "1 symbol per second"? Why do you CARE? I want to send the most information using the least bandwidth. >>The minimum voltage should be set to 1.6e-19 volt. This is the voltage of >>one electron. > Wrong. Electrons have charge, expressed in coulombs, not > voltage. Go figure out the difference, and come back. A charge can generate a voltage. An area with one free electron vs. a area with no free electrons has a difference of 1.6e-19 volt because a single electron has a negative charge of 1.6e-19 coulomb. >>The bit-resolution should be high enough that each "level" is a difference >>of 1.6e-19 volt from the level above/below. A resolution of 8-bit allows >>for only 256 different levels -- obviously *way* too low. > Way too low for WHAT? Deciphering all those voltage levels with differences of 1.6e-19 volt and with 1.6e-19 volt being the lowest voltage and the maximum voltage being just low enough *not* to do any of the following to any extent: 1. Exceed the dielectric strength of any electronic component 2. Generate temperatures above 70 Fahrenheit in any electronic component 3. Ionize any electronic component 8-bits of resolution simply isn't *nearly* enough for this task. >>The original Y signal is converted to QAM. This QAM signal is then >>broadcasted on an FM radio carrier wave whose base frequency is 300 Hz. >>300 Hz is the lowest ULF frequency and the lowest frequency used by >>telephones. > Restating nonsense doesn't make it less nonsensical. What does > "QAM...on an FM radio carrier wave" MEAN on your planet? A QAM signal in broadcasted on an FM radio wave. What don't you understand about this? > The rest is just gibberish as well. How so?
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Andy Champ
Date: Thu, 01 Nov 2007 20:10
Date: Thu, 01 Nov 2007 20:10
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Bob Myers wrote: > > Trust ye not in Wiki. "Baud rate" NEVER meant the same as > "bit rate" - the two just happened to be the same number in > early 1 bit/symbol systems. > > Bob M, > > That article was mostly right when I looked at it, or I wouldn't have mentioned it. Some odd stuff about gigabit ethernet now though... Andy
Re: Using an FM-Carrier for the Y [Luminance] Signal -- how to relieve the bandwidth issue?
Author: Green Xenon [Radium]
Date: Thu, 01 Nov 2007 21:27
Date: Thu, 01 Nov 2007 21:27
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Green Xenon [Radium] wrote: > Deciphering all those voltage levels with differences of 1.6e-19 volt > and with 1.6e-19 volt being the lowest voltage and the maximum voltage > being just low enough *not* to do any of the following to any extent: > > 1. Exceed the dielectric strength of any electronic component > > 2. Generate temperatures above 70 Fahrenheit in any electronic component > > 3. Ionize any electronic component > > 8-bits of resolution simply isn't *nearly* enough for this task. The reason is because there are obviously a *lot* more than 256 voltage levels in the above. > A QAM signal in broadcasted on an FM radio wave. Sorry. That should read "A QAM signal *is* broadcasted on an FM radio wave." F--king typos!
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