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RGB to CVBS

jdahl

New Member
Thread starter #1
Hey guys..

I need to convert an RGB over to a CVBS (Composite video). Anyone know a easy way to do that ? And anyone know where i can get an circuit, that I can use. ?

Johannes
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
#2
For a start fill your location in! - or how do we know what colour system you use!.

Also, tell us EXACTLY what you're trying to do, as there are a number of reasons why it might not be possible under many circumstances!.
 

jdahl

New Member
Thread starter #3
I live in norway so the system is PAL.

My project is to monitor two video sources at the same time on one tv screen, with the help of picture in picture (PIP). The PIP IC I use is called PVP9390A
( http://www.micronas.com/products/by_function/pvp_9390a/product_information/index.html ).
But the problem with this is that I only get an RGB or an YUV signal out... So my question is.. Is there a "easy" way to make an circuit without using IC such as AD725.(RGB ->CVBS converter).

The reason for needing the CBVS-output is because i can`t sendt more than one signal through the wireless system...
 
#5
I would like to introduce myself, I'm jdahl's partner at this school-project.
I've been looking at the motorola MC1377, but our chip needs to be able to work at -20 degrees celsius. And that chip copes with "only" 0 degrees celsius.

Seems like we need to use the AD725 afterall, no biggy, but just wanted to see if there were more altarnatives. Thank for the help!

Paul
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#6
furyfax said:
I've been looking at the motorola MC1377, but our chip needs to be able to work at -20 degrees celsius. And that chip copes with "only" 0 degrees celsius.
I would be surprised if the MC1377 didn't work fine at -20 degrees, the specification is simply a normal domestic one - only military and industrial parts are usually specified at a wider range. This doesn't mean the chip is any different, just that it's not been tested at that range.
 
#7
Maybe so, but this is our final school project and we're developing a prototype-module for a company. And the company has told us that the module has to able to work in enviroments as -20 degrees, they have demanded this.
So even if the MC1377 may most likely work I can't take the chance, since it's not properly tested.

Anyways, I've ordered 2 AD725 samples. They seem very easy to use.
Maybe we'll make a new thread and describe more details about our project.

I know we'll have some problems at some point of time, and this forum seems to be excellent in getting hint, tips and expertice.
Thank you for your replies!

Paul
 
#8
In the datasheet to the AD725, it says "Pin 3: 4FSC Clock Input For PAL (in my case) 17.734475MHz."
I can't seem to find an oscillator which has this frequency, or am I completely blind?

Paul

PS. This post got edited, my last post was built on a misunderstanding, therefore instead of writing new post, I edited this.
 
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#10
furyfax said:
And the company has told us that the module has to able to work in enviroments as -20 degrees, they have demanded this.
Don't you have acces to a climatic chamber?

All you need to do is buy some and test them to -20 to see if they work. I remember doing this when we we're selecting a hall effect current sensor for a design at work.
 
#12
Just because the device has to work in -20 degrees doesn't mean the chips have to. Just heat the enclosure, in an enclosed space the board is going to provide some natural level of heating anyways.
 

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