video signal problem

[xcoder]

this is ma first post sorry for ma bad english

my problems is about compiste video sync B&W composite video so there is no decoding no pal no secam no ntsc

i received a autorefractometre from friend that have integret camera problems so basicaly an autorefracto is text imposed on camera video singal !!
so now the camera cells failed and didnt found the part becose its a bit old
so the schema is like
the camera is connected to motherboard and motherboard mix camera composite video signal with text video signal to the monitor !! so now i want to install another camera and when i did syncs didnt get on the same frequency so my question is there anyway to change my camera syncs or somehow remove syncs from camera and insert back the text syncs to fit in the same frequency ????
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every vcc have a gnd if not please chose another job !!

[vtech]

I am not familiar with refractometer but I think I undrestand what you are trying to do. I am afraid it is not as easy.
In general, transposing text over composite video is very "unit specific" and there are no easy ways around it.
While there are standards for composite video, there are none when it comes to superimposing text. Without knowing the hardware specification, it would be more like a science project.

[xcoder]

yeah dude its very hard im trying now for like 3 month i tryed genlock separators AD ics

everything that i can nothing

there one way is to modify clock to fit same frequency but im 100% it will not work becose i have no idea how much trame line there is on the signal
_________________
every vcc have a gnd if not please chose another job !!