IC for video amplifier and filter

Discussion in 'The Projects Forum' started by roboticvn, Jul 9, 2014.

  1. roboticvn

    Thread Starter Member

    Jul 9, 2014
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    I am making a transmit video signal circuit. I need an IC to amplify and filter the video signal. Can you show me ic how best to do this job. Thank you ^^
     
  2. crutschow

    Expert

    Mar 14, 2008
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    What type of video signal and over what medium do you want to transfer it?
     
  3. roboticvn

    Thread Starter Member

    Jul 9, 2014
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    I want to transmit composite video signal (NTSC) which uses 3.58MHz sub-carrier frequency. The signal after amplification is taken into pulse width modulation. Can you tell me what the best IC for this work? Thank you^^
     
  4. BeerBelly

    New Member

    Dec 16, 2013
    29
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    What frequency would the pulses be. I expect the PWM would need to be 20 mhz or more.
    40 mhz would be better.
     
  5. roboticvn

    Thread Starter Member

    Jul 9, 2014
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    0
    Frequency of pulses is 15MHz. What IC I should use?
     
  6. MrChips

    Moderator

    Oct 2, 2009
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    I cannot see how you are going to succeed in transmitting a 40MHz video signal with a 15MHz PWM signal.
     
  7. roboticvn

    Thread Starter Member

    Jul 9, 2014
    47
    0
    No, I want to transmit composite video signal (NTSC). The linear ramp carrier signal at a frequency of 15 MHz
    [​IMG]
    It here http://forum.allaboutcircuits.com/attachment.php?attachmentid=70600&stc=1&d=1404996227. I get it on the Internet but it doesn't have hardware information. Can you help me? Addition, can you tell me how does filter work? Thank you^^
     
  8. MrChips

    Moderator

    Oct 2, 2009
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    I can't help you because I don't think it will work.
     
  9. DickCappels

    Moderator

    Aug 21, 2008
    2,646
    631
    You can firs try this without the filter or the amplifier, and if you test with a test pattern that does not change with time, you can connect the video to a DC restore (AKA clamp) circuit to the comparator. You will need a pretty fast sawtooth; I suggest 4x subcarrier otherwise you will get terrible beats between the sampling sawtooth and the subcarrier. Use a fast comparitor like the LM710.

    Later you can add a 4.5 MHz low-pass filter to the input.

    The circuit below includes an clamp and an 3.5 x amplifier. Adjust R29 to change the gain.

    [​IMG].
     
  10. roboticvn

    Thread Starter Member

    Jul 9, 2014
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  11. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,963
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    It does mention some ics for video and audio, TVL3502 op amp, Si1563 mosfet, AK5386 ADC,

    its using optical transmission of video and audio using a pwm carrier of 15Mhz at a distance of 50 to 100 cm.
     
  12. roboticvn

    Thread Starter Member

    Jul 9, 2014
    47
    0
    TVL3502 is used as a comparator. AK5386 is a ADC. I need a IC for amplifier and filter video signal. This isn't mentioned in journey.
     
  13. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,963
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    well have a search for Ntsc video amps, check out this from LT
     
  14. BeerBelly

    New Member

    Dec 16, 2013
    29
    5
    Another video amp with filtering you may try OPA360.
    Part and data sheet is at Mouser.com
     
  15. roboticvn

    Thread Starter Member

    Jul 9, 2014
    47
    0
    Thank you everyone's help^^
     
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