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Analog to Digital

  1. Sep 22, 2004 #1
    from analog to digital(PCM/QAM)

    I want to convert analog to digital.

    I am recording analog signals in my firm and i want to make a programm witch helps me to decode fax informations.

    if you know how to decode this analog signals witch is modulated with PCM/QAM, please help me.
  2. jcsd
  3. Sep 22, 2004 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Obviously, you'll need an ADC and a DSP. If you could tell us more about your system, we can be more helpful. Of course, you might want to consider hiring a contractor with the appropriate skills.

    - Warren
  4. Sep 22, 2004 #3

    now i have connected with line in cable to the my phone cable. i am sending faxes to another line and recording it's analog signals with sound forge.

    i have documentation about qam but i cant get any digits from this vawe files.

    i am searching algorithm how to demodulate analog signals and get fax data as tiff, bmp or jpg or another fortmat
  5. Sep 22, 2004 #4
    This product might help you: http://www.vectronics.com/vectronics/products.php?prodid=VEC-1613 [Broken]
    Last edited: May 1, 2017
  6. Sep 23, 2004 #5
    I not need any products.
    I want to write a program wich will be integrated in my system.
  7. Sep 23, 2004 #6
    i am paralell connected to the analog phone line witch is using to send/receive faxes.
    i am recording this analog signals in vawe/pcm format.
    i know how fax protocol is working, but i don't know how modulates digital signals to analog... and how to demodulate analog signals and get digital data.

    i am askign you...
    if you have any documentation about fax modulation or you can help me, please make it now.
  8. Sep 23, 2004 #7


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    Science Advisor
    Gold Member


    You're essentially asking us to give you a university-level education on signals and digital signal processing. It's quite simply outside the bounds of what we can teach you on an online forum. I suggest buying some books, or taking some classes. You need to learn quite a bit before you can do what you're trying to do.

    - Warren
  9. Sep 23, 2004 #8


    i know how analog and digital signals work.

    but i need documentation about fax modulation.

    i can't find this documentation.

    if you know where i can get this documentation please tel me.
  10. Sep 25, 2004 #9
    Goto Google and look under Facsimile Coding Schemes
    I think you will find all the information you need.
  11. Sep 25, 2004 #10
    if you know how to decode this analog signals witch is modulated with PCM/QAM, please help me.
    SIGNALS FROM ANALOGUE TO DIGITAL,use a programming language
    to capture-decode-manipulate-present digital data,there's very little
    decoding left to do,just get fax protocal details to give an idea what
    you have to do with the software
  12. Sep 25, 2004 #11
    i suggest you buy from a vendor that provides you with complete
    tools--hardware-drivers-libs and make sure your programming language
    is compatible with those
  13. Sep 25, 2004 #12
    i know what is qam and pcm.
    i have files witch is recorded as pcm wav file.
    i know fax is using qam for modulation/demodulation of digital data to/from analog sygnal.
    i know how to get tiff images from the digital data, but i don't know how to connvert this analog signals.
    i have documentation about modulation, but it not like the really situation and not works properly.
    i searched this info in google but no answer.
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