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Need a simple NTSC CVBS color bar and flat color field video source

Question asked by dblaker on Nov 1, 2012
Latest reply on Nov 2, 2012 by dblaker

I need a CVBS NTSC video source that can produce color bars and also a flat field of color.  Many parts, ADV7174, ADV7340, etc, will generate an SD color bar pattern with an internal signal generator.  The color field is harder to figure out.  I'm looking at three options:


1.  The ADV7340 can also make a black field.  Can I use the SD Y scale, or Cb, CR scale or hue adjustment to change the black field to a color. 


2.  Or can I use the encoder in master timing mode and just put a static RGB value on the input port? 


3.  The last option is an ADV7180 decoder in free run mode with no CVBS input.  In that mode I can change the no signal color it outputs.  The CCIR656 output can go to an encoder to make the CVBS output.  This now requires two chips.  I can easily test this out with a ADV7180 eval board that I already have.  It has a ADV7391 encoder.


The application is an in house tester for video displays.  We'll build 50 to 100 of them.   So low BOM cost is good but lowest development effort is more important.  I've tried the Parallex propeller chip but it's color quality is poor.  The BOB-4 from Decade Engineering doesn't generator color.  Raspberry Pi is just cheap but requires 5W of power which is a bit too high for my enclosure.  I've seen articles using Atmel or PIC processors but they then need an RGB to CVBS encoder. 

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