Connect with us

A possible cure for FCC bandwidth woes.

Discussion in 'Electronic Repair' started by feklar, Aug 18, 2003.

Scroll to continue with content
  1. feklar

    feklar Guest

    The explosive growth of the mobile phone industry has crowded and
    tangled the nation's airwaves to such an extent that wireless company
    signals are increasingly interfering with emergency radio frequencies
    used by police and firefighters, public safety agencies said.


    A cure?

    I may know of a way to broadcast 10 to 12 NTSC TV stations from a
    single antenna using a hundredth or less of the 4 mHz bandwidth it
    currently takes to broadcast a single NTSC video channel.

    It may work, it may not. It would have to be looked into. That
    DirecTV works leads me to believe that this method would also be
    valid.

    The basic principle would be to use one of the varous materials that
    are electroreactive, like many silver and cesium compounds, for the TV
    station transmitter tube cathodes.

    The modulation pattern would be imparted using either a laser or an
    x-ray source to irradiate the cathode, thereby introducing tiny
    fluctuations into the output signal.

    The transmitter would broadcast one narrow band frequency, say at 500
    mHz for example, with a bandwith similar to or smaller than an FM
    radio station.

    No other modulation would be applied to the output (power
    transmission) tubes except this tiny signal.

    Just bear with me, it gets better.

    Now say use a standard very high data rate beam chopper if using a
    high powered laser to irradiate the cathode, the chopper modified with
    lead plates if x-ray beam chopping is required. Since x-rays are
    inherently more powerful, x-rays are likely to be the correct
    irradiation source

    The idea is to irradiate the catrhode with tiny, very short duration,
    but very high powered pulses.

    Obviously, the transmitting tube will have to be cooled to increase
    the sensitivity (decrease the rise time and fall time) of the cathode
    materiel. The cathode should be a laser etched block, etched to leave
    large numbers of rows of microminiature towers or posts sticking up
    from its surface to increase the surface area and provide better
    cooling (with a high pressure supercooled gas) so as to decrease the
    rise and fall times.

    Looking at the received signal output with a standard type of VHF
    receiver with an oscilloscope, there would be no sign of these tiny
    introduced disturbances.

    So we need a specially designed receiver to process the received
    signal.

    Whatever the transmitter frequency is, have the user select that
    frequency (channel). Inside the reciever, a phase locked loop
    generator will tune to the signal and kickstart and maintain a
    seperate oscillator circuit at the same frequency.

    The idea here is to have the receiver generate the exact same
    frequency, and match it to the received signal in phase and power
    level without making an exact copy of the received signal, using a
    seperate "clean" pure oscillator circuit.

    Then this pure signal can be inverted 180 degrees out of phase and
    applied to the original signal. Once this is done, all that will
    remain is the very very tiny stream of pulses that had been imparted
    at the transmitting cathode by the laser or x-ray source.

    It could well be that the signlal will be so small that shielding the
    receiver and oscialltor circuits will not be enough, they may have to
    be cooled or supercooled with a microminiature liquid nitrogen system
    or better, a Peltier thermo electric cooler chip.

    Mass produxced, neither of these would be any significant cost
    consideration. Peltiers are already mass produced. Nitrogen would be
    much more energy efficient than a Peltier.

    No doubt Peltiers at first because of the cost considerations of
    designing a micro liquid nitogen system... but later, nitrogen.

    The tiny train of pulses would then just barely be visible on an
    oscilloscope of the canceled carrier output processed by the receiver.

    Obviously some very high speed fast reactance semiconductor components
    would be required, gallium arsenide or YAG rather than silicon or
    germanium.

    Three very low noise amplifier stages later the signal should be
    usable. This is the question: Will the pulses be large enough to be
    processed? If they can be made large enough, then this concept is
    valid.

    Use analog simulated digital for the signal. It has a high error rate
    but is still completely acceptable for this application.

    In other words, modulate the output power of the irradiation laser or
    x-ray source to provide each pulse with a power level of 0 to 255.

    This way, two pulses are all that would be required. One for chroma,
    the other for luminance.

    Now obviously there will be a very high error rate, but an error would
    only affect a single pixel, making the brightness of that pixel ever
    so slightly inaccurate, or the chroma ever so slightly inaccurate.
    This of course is assuming strong signal, no serious noise, and good
    sending and receiving conditions.

    Just stick with me here, I will be the first to admit that this syetem
    would be much, much more susceptable to noise than standard NTSC, but
    there are ways around this seemingly insurmountable problem.

    For one, a modified type of CRC error correction can be used. It can
    be one CRC per pixel (cuts transmission capability by a third), or one
    per scan line. Or it can be similar to ECC as used in hard disks, for
    8 or 16 pixels in each sample.

    First you have to go oover the decoding method before you can
    understand some of the higher order forms of error correction that can
    be used.

    What we need are memory gates and a slight time delay. As each line
    of scan is received, insted of being output to the display, instead it
    gets stored in RAM. Say we have storage for 5 complete screens in
    RAM. Using a FIFO, and a circular buffer pointer, as each new screen
    (NTSC - 30 screens per second) is received, it is stored in its own
    page of RAM. When the fourth screen begins being received, the first
    one that had been received begins being output to the display device.
    and so on using the buffer in a circular arrangement. As each new
    screen comes in the oldest one gets output to the display.

    This method allows considerable noise reduction potential.

    First, consider snow. In standard positive picture phase NTSC, snow
    is white. Error pixels show up as white or grey dots in the screen,
    the more noise, the more white pixels.

    This setup uses negative picture phase inversion, and error pixels are
    black. So, the result of random noise is not visible interference on
    the display but instead, a reduction in overall screen brightness.

    How can we find error pixels? One method is to use the banks of RAM
    and apply a control program and the appropriate logic. For example,
    one yellow pixel in a sea of green ones is probably an error. Color
    area changes are almost always either drastic or gradual. Rarely if
    ever does just one purple pixel show up in a green area.

    When there is a question such as this that arises, the pixel that may
    be in error can be rejected as erroneous and replaced with one taken
    from averaging the values of all the pixels surrounding it.
    Obviously, the logic must extend past the surrounding pixels becasue
    there are cases of one yellow pixel for every 30 green ones used as an
    area tint. Area tint patterns can be analyzed and left alone if they
    show a repeating pattern.

    We also have more than one screen to deal with. After the
    generalities of the given screen are analyzed by a CPU, error pixels
    can be replaced with the pixel from the previous screen which is still
    residing in RAM. Even after a screen is output to the display it will
    remain in RAM for four more screens before being overwritten.

    In cases where there is doubt, the pixel can be blacked out as well,
    resulting in a tiny reduction in screen brightness.

    Obviously, there will be times when many lines worth of pixel values
    exceeding 255 will be received, but instead of showing these as black
    lines on the display, the pixels from the ast good screen can be
    displayed.

    All of these methods are well within the tolerance of the eye not to
    be able to discern. The eye is not fast enough to detect even a 50
    percent error rate in erroneously "corrected" pixels. This is
    especially true for averaged replacement pixels.

    Given the random nature of noise, some noise will cause a general
    reduction in display screen brightness, but using the above methods to
    replace bad pixels with good ones from previous screens will limit the
    scale of the reduction considerably.

    There are other more sophisticated approaches to using CPUs to analyze
    the screens stored in RAM but the basic ideas above illustrate a few
    of the basics well enough, and space is limited here.

    Remember, the dot rate for NTSC is 12 mHz, (the pixel rate is 24 mHz
    using two values per pixel, chroma and luminance) which means a 80386
    CPU running at 50 mHz could accomplish a fair amount of processing
    given the proper hardware logic gates to work with. Obviously, a
    Pentium 500 running multitasking could process numerous logic analysis
    activities on multiple banks of RAM.

    If the method works, it should be relatively easy to interleave 10 or
    12 channels onto a single data stream. Then at the reciver, the
    channel selector is used first to pick a transmitter, then to choose
    and deinterleave one of the channels contained within that frequency.

    Figure using a one gigahertz data rate. Even using a CRC correction
    "byte" for each pixel, this means the NTSC dot rate of 12 million
    pixels per second times three (ECC, chroma, luminance), or 36 mHz.
    How many 36 mHz signals can be interleaved into a 1 gHz data rate? 25
    channels, with 2.7 mHz left over. I suspect that the use of ECC or
    CRC would be much more agressive, which is why I said 10 to 12
    channels rather than 25. Also, we still have the audio channels to
    consider, probably some form of MPEG with error correction.

    So if 12 channels were used, it would reduce the airwaves requirement
    for 12 currently operating TV channels from (12 * 4 mHz) 48 mHz, down
    to less than 1 mHz. Not considering the audio channels it would free
    since they are far less bandwidth intensive.

    But in terms of electrical power use, those audio transmitters aren't
    so insignificant, and neither are the video transmitters. If this
    concept proves valid, it would save more than a constant gigawatt of
    electricity in the USA alone.

    Obviously, in the receiver you need high speed gallium arsenide chips
    to convert the power level of each received pulse to a digital
    value... This same circuit would contain the deinterleave selector
    circuitry.

    Obviously, the transmitter needs to send time base data periodically
    for deinterleaving synchronization.



    now you are really screwed
    http://www.infernalpress.com/Columns/election.html
    http://www.scoop.co.nz/mason/stories/HL0307/S00065.htm
     
  2. Uns Lider

    Uns Lider Guest

    This won't work. As soon as you modulate the carrier with high frequency
    signals (pulses), it starts taking more bandwidth. Shannon's law.

    -- uns
     
  3. Err..its got absolutely nothing to do with Shannons law. Its a
    mathematical identity. Given, e.g., V(t)=A(t).Sin(B(t).f + c(t)), then a
    mathematical expansion will show a host of frequencies.

    Kevin Aylward

    http://www.anasoft.co.uk
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
     
  4. This whole thing is totally hosed. If the original signal shows no sign of
    this information, then no receiver, regardless of its design, will have a signal
    to work with. End of wild speculation.

    Cheers!

    Chip Shults
    My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
     
  5. Looks like a pipe dream to me.

    It would be better to just get rid of all broadcasting thru the
    airwaves. Every dwelling, etc., would he served by a fiber optic
    cable with the whole broadcast band, AM, FM, TV, etc. on it. That
    way, the BW used by broadcasters could be reused for mobile devices,
    such as PDAs, etc.
    --
    @@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@,@@[email protected]@[email protected],@@[email protected]@[email protected]@[email protected]@
    ###Got a Question about ELECTRONICS? Check HERE First:###
    http://users.pandora.be/educypedia/electronics/databank.htm
    My email address is whitelisted. *All* email sent to it
    goes directly to the trash unless you add NOSPAM in the
    Subject: line with other stuff. alondra101 <at> hotmail.com
    Don't be ripped off by the big book dealers. Go to the URL
    that will give you a choice and save you money(up to half).
    http://www.everybookstore.com You'll be glad you did!
    Just when you thought you had all this figured out, the gov't
    changed it: http://physics.nist.gov/cuu/Units/binary.html
    @@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@
     
  6. Active8

    Active8 Guest

    i'm not arguing with or even repling to you specifically, kevin. i guess
    you just got lucky ;-)

    the reduced spectral power density *would* cause less interference, but
    it wouldn't travel as far. spread spectrum accomplishes reduced
    interference because no two TX's spectral lines occur at the same time
    and if they do, error correction deals with it. SS also realizes a
    processing gain so there's a better SNR.

    why reinvent the wheel with something more complicated. now that sat tv
    is beginning to carry local channels we'll hardly need off-air. i don't
    see any reason for so many off-air channels anyway.

    funny thing is... with all this high falutin' talk of electroreactivity,
    where'd the basic concept of bandwidth, fourier, channel capacity, etc.
    get lost? under the piled higher and deeper?

    as for the "loopiness" of OP's idea... the psuedoscientist i worked for
    had an equally, if not more so loopy idea. don't transmit an electrical
    entity, transmit an electrical non-entity. all we could demonstrate was
    the ability of a phone line to be used as an integrator. how that guy
    could (with a history degree) talk all kinds of nyquist, shannon, and
    other stuff, and not realize that you can't use a divider to stretch a
    series of random data pulses without losing data is beyond me. oh and
    i'll never forget his solution to the inband noise coming out of my
    filter. he asked me if i couldn't filter it out.

    "sure fred, i'll just filter the noise at fc and lose the signal i want
    at the same time. here, i'll just cut the signal here. see, no more
    noise :)" pointy-haired p.m.s ... i've got dilbert strips with "fred"
    written over the p.h.p.m.

    mike
     
  7. Asimov

    Asimov Guest

    "Uns Lider" bravely wrote to "All" (18 Aug 03 09:47:50)
    --- on the topic of "Re: A possible cure for FCC bandwidth woes."

    UL> From: Uns Lider <>

    UL> This won't work. As soon as you modulate the carrier with high
    UL> frequency signals (pulses), it starts taking more bandwidth. Shannon's
    UL> law.
    UL> -- uns

    Speaking in theory, what about for instance, transmitting complete
    sinewaves but one at a time as the "bit". Couldn't a 500MHz carrier
    result in a 250MHZ channel with 0 sidebands if it was possible to chop
    the transmitter cleanly at that rate?

    Asimov
    ******

    .... Batteries not included.
     
  8. feklar

    feklar Guest

    I didn't say there would be no signal, only that it would be so tiny
    as compared to the amplitude of the sine wave carrier that it would
    not be visible on a scope. Once the sine wave of the carrier was
    removed, the pulse train would be visible once the sensitivity of the
    scope was increased.

    now you are really screwed
    http://www.infernalpress.com/Columns/election.html
    http://www.scoop.co.nz/mason/stories/HL0307/S00065.htm
     
  9. feklar

    feklar Guest

    This is why the bandwidth wouldn't increase significantly.

    The idea is to just introduce very minor perturbations or
    inconsistancies into the pure sine wave of the carrier, adding short
    pulses that do not overlap one another, basically making the sine wave
    slightly "noisy".

    Compare the idea to laser or radar surveillance, where vibration on
    the reflecting surface modifies the shape of the reflected pure sine
    wave.

    The principle would be very similar to laser or radar surveillance
    except that the modulation is introduced electrically directly rather
    than introduced physically via a reflection, and is much smaller in
    magnitude, and as pulses rather than a sine pattern overlaid onto
    another sine pattern.

    Radar and laser surveillance are both proven valid concepts, this idea
    just takes some of that basic underlying principle and considerably
    pushes its limits.

    now you are really screwed
    http://www.infernalpress.com/Columns/election.html
    http://www.scoop.co.nz/mason/stories/HL0307/S00065.htm
     
  10. John Larkin

    John Larkin Guest

    On Mon, 18 Aug 2003 08:11:23 GMT, (feklar) wrote:

    ....


    Wow, that's an awfully long joke, considering that it's not at all
    funny. Wouldn't your time be better spent doing laundry or something?

    John
     
  11. feklar

    feklar Guest

    Good idea. But with everything going to wireless and satellite, where
    are the phone companies and cable companies going to come up with the
    money to implement it?

    Almost serves them right, spending the money that should have been
    used on upgrading to fiber cable and living high off the hog, and in
    the process being responsible for their own demise...

    I would have expected more from US Sprint...

    now you are really screwed
    http://www.infernalpress.com/Columns/election.html
    http://www.scoop.co.nz/mason/stories/HL0307/S00065.htm
     
  12. Ho hum... Your trying for a free lunch. It aint goanna happen.

    Kevin Aylward

    http://www.anasoft.co.uk
    SuperSpice, a very affordable Mixed-Mode
    Windows Simulator with Schematic Capture,
    Waveform Display, FFT's and Filter Design.
     
  13. Active8

    Active8 Guest

    psuedoscience. the spectral lines might not occur simultaneaously, but
    that impacts interference between transmitters operating in the same
    band, not bandwidth. the spectral power density is another story. trust
    me, these miniscule pulses won't make it very far at all.

    google ultra wide band or UWB. you'll see that you can just broadcast
    narrow pulses without a carrier and it'll splatter all over the
    spectrum. the reason they get away with it is LOW POWER as in wireless
    LAN or maybe collision radar, as in local, as in forget it. increase
    power and change FCC rules? good luck. the FCC already approved UWB and
    set the power limits to protect other services. before that, it was
    CDMA, FHSS, TDMA, and all that.

    br,
    mike
     
  14. True. The moment one mentions "tiny, very short duration...pulse",
    one thinks of a signal with correspondingly infinite bandwidth, being
    multiplied by fixed-frequency signal, so the convolved signal is
    spread very nice and wide.

    Keep trying though. :)

    -Chaud Lapin-
     
  15. John Larkin

    John Larkin Guest

    On Mon, 18 Aug 2003 17:16:38 GMT, (feklar) wrote:


    Good grief, you're serious!
    But information theory did.
    You don't need experiments. All the relevant theory has existed for
    about 50 years or so, and has never been shown to fail.

    Really, you should get a book on communications theory. All this stuff
    is understood. Google Nyquist, Claude Shannon, communications theory,
    and the Sampling Theorem for starters.

    John
     
  16. Every day, scores of bright people re-invent all kinds of things,
    like:

    motors hooked to generators hooked to the same motor to
    generate power for free...

    buckets on an escalator that fill up with water, pull themselves down,
    punping the water back up to refill then buckets...

    Ways of imposing several signals on one carrier, or narrowing the bandwith
    (easy on a FM transmitter!),,,,

    Magnets that pull a iron plate down, which slides the magnets out of the
    way,
    which releases the plate, which slides the magnets back....

    Reading overwritten data on a disk by subtracting out the new data.

    Writing an operating system with volunteers, who boot up the system and use
    it to spiff up the system.... Wait! that kinda works!


    All the other bright ideas violate some really basic principle.

    Keep on thinking, just remember there's no free lunch.
     
  17. feklar

    feklar Guest

    No I never went the perpetual motion route, I learned enough about
    friction to know that a steady state machine is not possible.
    There is a battery based on a motor generator using superconducting
    wire. Sort of like an electric flywheel...
    This is possible. When data is written to a data track it begins
    immediately expanding in size physically. Each new track that
    overwrites an old one fails to overwrite the edges of the track, and
    the original data can be read by reading the outer edge instead of the
    center of the track. Data can be recovered this way even after it has
    been overwritten 10 times, although it takes some pretty sensitive
    equipment to do it. There is a vast amount of information available
    on the web regarding this. The NSA and DOD documentation is some of
    the better trechnical stuff...

    http://search.yahoo.com/search?ei=UTF-8&fr=sfp&p=security+data+"hard+drives"+military+disposal
    http://www.computing.co.uk/News/1123092
    http://www.k4d4th.org/pub/crypto/cryptome/afssi5020.htm

    AIR FORCE SYSTEM SECURITY INSTRUCTION 5020
    20 August 1996
    3.1.2. Sanitizing.

    3.1.2.1. Degaussing Type I, II, and III magnetic tapes is the only
    method approved for sanitizing this media. Use a Type I degausser to
    sanitize Type I tapes or a Type II degausser for Types I & II tapes.
    Refer to NSA’s Degausser Products List (DPL) for availability of Type
    III (extended range--above 750 Oersteds (Oe).) degaussers that are
    capable of sanitizing Type III tapes
    True.

    Like I said, I didn't know whether the concept would be valid or not.
    I've talked about the idea for about 13 or 14 years now, but for some
    reason I never thought to post it here where someone might actually be
    able to follow it and have the background and knowledge to be able to
    analyze and assess it.

    now you are really screwed
    http://www.infernalpress.com/Columns/election.html
    http://www.scoop.co.nz/mason/stories/HL0307/S00065.htm
     
  18. feklar

    feklar Guest

  19. The solution these days is to INCREASE bandwidth, not reduce it.
    That's what UWB and impulse radio is all about.

    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email: fax 847-574-1462

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  20. Read Vitribi to realize how absurd your claims are.

    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email: fax 847-574-1462

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-