composite video signal problem

[xcoder]

hi all im yassine from morocco nice forum you got

so ma problem is not that simple from ma point of view
i got 2 video signal mixed digitaly thrue a mother board
first signal is a camera second one is a camera ccd
the two signals are composite b/w signals
camera cell is broken so no remplacement becose support doesnt have it anymore !!!
so i replaced the camera with a small ccd camera but sync arnt the same !!!

so is there anyway that delete sync from ma new camera and get only video signal and then insert the text video syncs so it be in the same sync !!!

please help guys

[xcoder]

common guys help me out !!!!!

[Metallica Man X]

What type of camera did you use? Is it NTSC, PAL, or what?

It could be that the motherboard you're using doesn't support the region type of the camera.

[xcoder]

the whole system is BLACK N WHITE SO NO NTSC OR PAL !!!

the problem here is the sync

2 signals with two diffrents syncs

first one is motherboard text sync and the second is the new camera so

what im asking is delete sync from new camera

extract syncs from motherboard text video singals inject them back to camera video

[DrZarkov]

What you ask for is a genlock. http://en.wikipedia.org/wiki/Genlock

[xcoder]

thanks alot brother im gonna do some research and i will reply soon if i successed

[xcoder]

thanks again but cant parts or the whole deal so becose im from morocco

if i want for exemple a 74hc04 i have to travel 40km to get it and not 100% sure

i have an idea i found it like 1 week ago and if you take alook at it

[Klaas Robers]

What you need is a video mixing table with a synchroniser. This is a (rather complicated) circuit that synchronises one video signal to another. If fact it is a memory that is filled by the first video signal and read by the sync of the second video signal. Now the two video signals are synchronous they can be mixed.

I have seen video mixer consoles of a moderate price that have this synchroniser built in. Two not synchronous video signals can never be mixed. It is not audio?

[DrZarkov]

Analogue video equipment for VHS is almost for free now at fleamarkets, or very cheap at ebay.

[xcoder]

the problem here is that i cant give the costyumer a mixer with his autorefractometre what i was asking is thatr how i can remove sync from composite video signal and inject it back to another signal thats all

[DrZarkov]

With a genlock.

[Lowtone]

What you need is a video mixing table with a synchroniser. This is a (rather complicated) circuit that synchronises one video signal to another. If fact it is a memory that is filled by the first video signal and read by the sync of the second video signal. Now the two video signals are synchronous they can be mixed.

http://www.ouedkniss.com/photos_annonce ... Photo2.jpg

I have this old Panasonic, it does the job very well

It has a Time Base Corrector Inside, wich is great to restor weak synch signals from VHS also.

[xcoder]

dude its autorefractometre so i cant use video mixer ,i need aa way or schematic to correct sync i need a modification

[Klaas Robers]

Let me try it once more:

In order to mix or to switch analogue video signals you need to meet TWO things:

1. The video signals need to be synchroneous. That is the horizontal sync and the vertical sync both need to come on exactly the same moment.

2. If criterium 1 is Ok, then you need to remove the sync pulses of both signals, mix the remaining video signals, and place a new (also synchronous) sync signal "under" this mixed video signal. This is relatively simple. It is the task the Intersil circuit may solve, but only if the signals are synchronous, which isn't obvious.

To see if criterium 1 is Ok, you may simply mix the two signals with two resistors of say 100 ohm and connect the result to a monitor. Then you will see the result.

- If both signals are synchronous you will see the mixed video.
- If they are not synchronous you will see a mess, on which the monitor may not be able to synchronise on.

In the second case you may mix the signals with unequal strengths, e.g. use a resistor of 33 ohm in one video signal and one of 330 ohm in the other. Now the monitor will synchronise on the strongest signal (the first) and you will see the second one weakly (10%) superimposed. You will see it horizontally and vertically shifted on the screen, in some cases even slightly moving.

Please do these experiments and report us on the outcomes. Then we can try to help you to a solution. Or not, then it is impossible.

Mixing video signals is far more complicated than mixing sound channels. Colour makes it even more difficult.

[Steve Anderson]

I can only but concur will all that Klaas says above. But one fundamental thing is are the two standards you are trying to mix the same standard, synchronous or not? You cannot directly mix a 625 signal with a 525 signal. To do this requires a standards converter....which (usually) will also do the re-synchronizing too...if it's any good....then you need a downstream mixer to do the dissolves/wipes etc...

Quite a few have been trying to answer your questions, but you have given us very little information....

Now an 'autorefractometre' sounds like a scientific piece of equipment, are you sure that its output is 625 as used in Morocco? If it needs a computer monitor to display its results the problem gets worse...

We have tried to help but you've given us very little information to work on...

Steve A.

Morocco uses SECAM B as its analogue colour standard, but that doesn't seem to be an issue here as the application appears to be monochrome.