Video chips theory

Discussion in 'General Electronics Chat' started by relicmarks, Apr 17, 2008.

  1. relicmarks

    Thread Starter Active Member

    Oct 13, 2006
    355
    0
    SN75176 chip ( video stripper or seperator chip )
    1.) This take input RED analog signal + vertical sync digital signal
    2.) Outputs ONLY the digital vertical sync signal

    3.) Takes input BLUE analog signal + Horizontal sync digital signal
    4.) Outputs ONLY the digital horizontal sync signal

    ** Is this a video stripper or seperator chip??

    EL5370 video chip ( the Video mixing,summing stage)
    1.) RED channel input
    Green channel input
    Blue channel input
    Vertical sync digital input
    Horizontal sync digital input

    2.) Outputs RED video analog channel + vertical sync digital signal
    Outputs Blue video analog channel + Horzital sync digital signal
    Outputs Green video analog channel signal

    ** What kind of mixing or Summing is this type??

    EL5372 video chip ( the Video mixing,summing stage)

    1.) RED channel input
    Green channel input
    Blue channel input
    Vertical sync digital input
    Horizontal sync digital input

    2.) Outputs RED video analog channel + vertical sync digital signal
    Outputs Blue video analog channel + Horzital sync digital signal
    Outputs Green video analog channel signal

    ** What kind of mixing or Summing is this type??



    EL2180 : Video Buffer/driver chip

    1.) This seems like a Video Buffer output or a video driver chip
    2.) The Feedback gain and components are weird
    a.) They RC components in "parallel" but the values are in STEPS in the feedback from the output pin to the input pin
    b.) 39 ohms with 56 pf
    c.) 390 ohms with 56 pf
    d.) 1K ohms with a 180 pf

    EL51621S : Video Buffer/driver chip

    1.) This seems like a Video Buffer output or a video driver chip
    2.) The Feedback gain and components are weird
    a.) They RC components in "parallel" but the values are in STEPS in the feedback from the output pin to the input pin
    b.) 39 ohms with 56 pf
    c.) 390 ohms with 56 pf
    d.) 1K ohms with a 180 pf


    EL2480 : Video Buffer/driver chip

    1.) This seems like a Video Buffer output or a video driver chip
    2.) The Feedback gain and components are weird
    a.) They RC components in "parallel" but the values are in STEPS in the feedback from the output pin to the input pin
    b.) 39 ohms with 56 pf
    c.) 390 ohms with 56 pf
    d.) 1.2K ohms with a 180 pf

    EL5362 : Video Buffer/driver chip

    1.) This seems like a Video Buffer output or a video driver chip
    2.) The Feedback gain and components are weird
    a.) They RC components in "parallel" but the values are in STEPS in the feedback from the output pin to the input pin
    b.) 39 ohms with 56 pf
    c.) 390 ohms with 56 pf
    d.) 1.2K ohms with a 180 pf


    EL5172- Video Differential input chip "Converts" to a video single ended output

    1.) This takes the "Differential" + and - Video input RED and outputs a "Single ended" RED waveform signal

    EL5372- Video Differential input chip "Converts" to a video single ended output

    1.) This takes the "Differential" + and - Video input RED and outputs a "Single ended" RED waveform signal


    ISL59448 video chip

    1.) This inputs RGB on seperate inputs
    2.) Outputs RGB on seperate outputs

    ** I don't know what they use this for and why they would use this ISL59448 video chip, but they use it for the Video output

    ** Why would they use this ISL59448 video chip?
     
  2. relicmarks

    Thread Starter Active Member

    Oct 13, 2006
    355
    0
    Video Buffer/driver chip name types:
    EL2180
    EL5162
    EL2480
    EL5362

    The feedback network stays the "SAME" But the Red,Green,Blue channel each have their own video buffers/driver chips
    So RGB seperate channels would have 3 seperate EL2480 Video Buffer/driver chip
    Example Experimental RGB test
    Tried out RGB seperate channels would have 3 seperate EL5162 Video Buffer/driver chip
    Tried out RGB seperate channels would have 3 seperate EL5362 Video Buffer/driver chip
    Tried out RGB seperate channels would have 3 seperate EL2180 Video Buffer/driver chip
    Tried out RGB seperate channels would have 3 seperate EL2480 Video Buffer/driver chip
    ** The RGB seperate signals looked different on each TEST why is that , the feedback network stayed the same but just changing the Video buffer/driver chip really makes a big difference
    What differences would it be?

    Why is the Feeback network in "parallel" with a Video buffer/driver chip?
    Why is the Feedback network in STEPS? look at the resistor and capacitor values that go in steps but why?
    They RC components in "parallel" but the values are in STEPS in the feedback from the output pin to the input pin
    a.) 39 ohms with 56 pf
    b.) 390 ohms with 56 pf
    c.) 1.2K ohms with a 180 pf
     
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