Hmm... so why do you think that Extron, UMSA, etc. bother using logic gates to combine the sync signals? I mean, in theory, that approach sounds more robust but I don't fully understand the reason for not using your approach (especially if it works).
Mostly because sync can also come with a positive/negative mix. Also, the incoming sync could be at various voltage levels, depending upon the source, yet still be converted/output at a consistent voltage etc. The creators of those devices would want to accommodate those variations in the interests of consistency, so that they can promote/sell their devices without caveats.
Maybe we're never meant to admit to such weaknesses, but I understand electronics sooooooooo much better than I did back when I started this hobby (which is a really good thing
), so I now know that making a sync converter is not really that difficult so long as you have the parts available (as many electronics hobbyists & professionals probably would). But when I was a n00b, it was all a bit scary (and unnecessary) so I chose the much easier option (twist & combine H+V sync, negative polarity on both in video card), with due care.
Either way, no reason not to take a properly formed C-sync straight from the video card now that Calamity's software supports it.
Yes, quite true that. I probably should click the c-sync box in VMMaker or wherever it is, even though I don't expect to see a difference in my image output. Note that it'll still be at max 5v levels!
I realised last night that my Fluke DMM actually has a 'max' function. That should be able to tell me the voltage of the sync pulses after the voltage divider (without having to visualise with an oscilloscope).
You can get a rough impression of video/sync pulses voltage range by just using a $5 multimeter from Bunnings, although this does also require you to use patience (and a little imagination) and is clearly lacks the precise accuracy of your fluke DMM or esp a oscilloscope.
One of these days I'll find a cheap ossc, or even learn how to make one out of an old CRT.