Electronics > Projects, Designs, and Technical Stuff
(List of SDI video ICs) Please help me find an SDI interface IC
<< < (3/3)
Yansi:
For starters, I'd stick with just the single CVBS to ST259 conversion. For that I'd probably not need any PLL loop*, just leave the free running clock from the CVBS digitizing circuitry.

Do all digital video switchers have a full frame buffers for every input, to be able to sync all (actively processed) SDI inputs? Obviously, SDI cameras are not frame aligned in any way against each other, are they?

I will need to look into how the LVDS is implemented in the Cyclone IV.

//EDIT: *Of course, still a x10 PLL is needed for the shift register, but that is only fed with the constant 27MHz input clock, no need to sync to any input data.

dmills:
Nope, SDI routers and switchers generally only have a few lines or so of buffering, certainly not anything like a full frame store on every input (Gets a bit impractical at facility router scale). What they have is basically to deal with lightspeed delays on the cabling, not randomly drifting sources.

The CCU (Camera control unit) generally takes a sync input (Often old school trilevel sync of all things), so yes cameras are generally locked to house sync, at least in the grown up world, difficult to do a clean wipe otherwise, even if there was a fame store on each input.

Now the low end stuff may ironically actually have more going on here (BMD) simply because their users are not expecting to have house sync and are probably not so worried about small amounts of delay.
Yansi:
Studio environment is probably genlocked, sure, but a small video production will not likely have genlocked cameras (neither will have I, hihi)

I then expect to need a full frame buffer memory to be able to compensate for unknown sync relations and clock drift :-/

(Black Magic Design stuff does not impress me that much, due to their stupid decision to use ST-424 level B signalling, so their equipment can't be interfaced with shit all. But that is just an offtopic rant...)
Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod