Video buffer IC quesiton...

[donsql]

So I need some advice.  I am trying to put together a circuit to split a video signal between two 80s CRTs.

I found an IC that should do the job, but all the example circuits use a 75 ohm resistor because most applications where for standard TV sets and devices using VGA which specify an impedance of 75 ohms.

The CRTs I am trying to use are not television sets and specify an input impedance of 1k-5k depending on model of the CRT.

I am only sending the signal probably 6 to 20 feet and have several sets of CRTs so one of my issues would prefer to just make a circuit that is exactly the same if possible.

Should I just leave them at 75 ohms?
Use an exact matching resistor to that monitors specifications (could get complex with all the different monitor models)?
Something say in the middle (ex 2.7k) might work?

[Manul]

Not sure if I understand question correctly, but idealy the cable should have source and destination termination both matching cable's impedance, usually 75 ohms for video lines.

Generally, if you have mismatched destination termination (you said your CRT is 1-5K), but you have proper source termination it will still be ok, reflections will be absorbed by source almost 100% and will not be seen by destination (just one reflection happens). Except that voltage levels at destination will be double. If you have both ends terminated, then reflections does not happen at all (idealy), so this is preferred. Also voltage levels will be what they should be (because usually the driver is made for destination termination to be present). If you have both ends badly terminated, then all kinds of funny business can happen with your signal.

So source should be 75, cable 75 and you probably need 75 on the CRT inputs (load termination).

[Benta]

You should terminate with 75 ohms at the CRT end. Otherwise your picture quality will suffer, especially at 20 feet cable.
Either make an adapter for the CRT end or solder in the resistors directly.

[donsql]

So here is the specs for the signal needed.

INPUT SIGNALS
• Video: RGB analog, 1 v to 5v peak-to-peak (adjustable with contrast control), 4. 7k ohm input impedance, 40 usec to 50 usec active video.

I am basically taking a 1980s arcade game PCB and instead of having it just drive one monitor I need it to drive two monitors.  If i just split the signal the monitors go dim so they need to be buffered.

More info I found researching:

Arcade video (standard resolution)
Video amplitude: 2-5Vpp
Video DC offset: yes, as much as a volt or two
Video input impedance: 1k-10k
separate horizontal and vertical sync (most of the time)
sync polarity negative (most of the time)