COMPOSITE video signal GENERATION! (PAL standard)

Discussion in 'The Projects Forum' started by anchit, Sep 9, 2009.

  1. anchit

    Thread Starter New Member

    Mar 3, 2009
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    0
    Me and a friend were making a project where in v were to produce a composite video signal of PAL(phase alternating line) standards....
    v were doing a standard VHDL coding to get d needed waveform and then implement it on hardware...
    the coding part v are done with...
    v made 2 codes...
    one in which the sync pulse and video signal are separate and d other one has combined sync pulse and video signal....
    m using the 1st code...
    keeping in my all the timing constraints i used 50Mhz as my clock signal and formed d sync pulse and a 3 bit number to get 8 different levels innd video signal(to get 8 different coloured bands)...
    software work is done....
    d code is correct and needs jus the synthesis...
    this is not a concern....
    V are now working on the hardware...
    after vl b applying this code to d FPGA board, v wil b getting standard TTL output for values of 1 and 0 (i.e. 3.3V and 0 respectively)
    V are using seperate sections for both d signals....
    setting a resistive nework to get 0 to 0.7 V range for d video signal...
    V also set another resistive network to set the value of d sync pulse to 0.3 volt....
    NOW comes my concern...
    being really out of analog study since long...
    V are not able to find d proper circuit to pull down the sync pulse from 0 to 0.3 v to -0.3v to 0 v.....
    V did try thinkin of a circuit using opamp but m not too sure..
    ALso to combine both the above signals v are plannin to use a summing amplifier....
    V need help in confirming our doubts!!!
    HOPING TO GET REPLIES SOON!!! :)
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    I don't even read posts that are written in text speak.
     
  3. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    Who is V? The aliens?
    [​IMG]
     
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