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analog to digital video

Discussion in 'Electronic Design' started by John, Jul 2, 2007.

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  1. John

    John Guest

    Posted a few minutes ago, but the subject, and the questions, were not
    a precise as I should have made them, so if you picked that message up
    in the two minutes it was posted, I am sorry to have misled.... :)

    Meanwhile:

    This is a rather generic question, as the standards, and final
    requirements, are not really well defined for me to deal with at the
    moment.

    A company I sometimes work for, sells character generators. They are
    analog output, and of course, in the broadcast world, that is not
    very appealing any more.

    I am researching alternatives to some very expensive "black box"
    solutions that they have been offered, to convert the CG
    analog output, to digital video. . These boxes they have used, are
    overkill, and include audio channels, which do not apply to the CG
    application in its broadcast application.

    Many head ends are using these kinds of 'black boxes' as a solution to
    the fact that they do analog commercial insertion, while the
    broadcasters are quickly moving to digital delivery. A stopgap
    method, but a
    popular one nonetheless, at this point in the changeover.

    I know there are many standards for DV. Just a generic question

    What I am searching for, is information and ideas as to how to create
    our own 'black box' that only converts video, more of a custom
    solution. The management is convinced this is doable, and so I have
    been tasked with finding out how to proceed.

    Its not my field of expertise, being an analog video engineer, but I
    think if I can find the basic requirements of the circuits, and
    hopefully the IC building blocks, I could handle it, or at least help
    provide them with a direction, even if I am able to do the job.

    Again, rather a generic inquiry, as opposed to all the dirty details.
    Can anyone point me to a source for such components, or discussions on
    this issue?

    Just hoping to get a road map, to find out how to proceed.

    Thanks very much for any suggestions or references.

    John
     
  2. Have a look at the TDA8754 from NXP (was philips).
    It is only 8 bit, and I think lots of video is 10bit now, then you
    will need someone to program a micro to control it, followed a smpte
    encoder, possibly, gennum or national do them


    martin
     
  3. joseph2k

    joseph2k Guest

    Well lets see, first how is the sync handled in the digital interface?
    Second, since the resolution is higher you will want to use more pixels
    (rows and columns) for your characters. Third, cut away the analog video
    portion and substitute a digital mux (if video bleed through is desired use
    adders). Then match the interfaces and the crying is over.
     
  4. John

    John Guest

    I do not know....
    I'm sorry, I didn't realize anything I said was crying. I am just
    wanting to know if anyone can point me to where to go to find the
    information, and hardware I might use, to see how this can be done...

    Thanks,

    John
     
  5. You need to open up the box, find out what ics drive the analogue
    output, and if they are not custom, look at the apporpriate data
    sheets, and figure out how to serialise the signal


    martin
     
  6. joseph2k

    joseph2k Guest

    Your management was doing the crying. Use your loaf.
     
  7. eedesignpro

    eedesignpro

    1
    0
    Oct 29, 2007
    Hi John

    You should have most of the circuits and signals in your generator to do what you want to do. You only need to size the analog video signal, convert it with an ADC there are many that you could use. To do the conversion you need a clock signal, todays clock rate of choice is 13.5Mhz. But almost any clock that is 3 times the expected bandwidth of the video signal would work. 10.7Mhz,14.3Mhz,17.7Mhz it should be the same clock as you use to generate the video signal in the beginning.
     
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