()blivion
Active Member
The signal is VGA 1024 x 768 15khz at MAX would this suit the chip?
VGA 1024 x 768 is called "XGA" and typically requires 65Mhz of bandwidth. I'm not 100% sure if that is total, or if that is for each line. I am almost positive the MC14551 will *NOT* pass that without causing massive distortion in the video quality, but you can try it. You will probably need a better chip. I will look for a generic demux with that kind of bandwidth in the meantime.
Also, what is exactly the 15Khz refereeing too? Horizontal refresh?
I am currently not using a relay setup its manual at the moment.
So... you haven't tried it yet?
Chances are, with that quality of video standard, you will get a good amount of distortion using relays. Especially if they are not small signal type. You also need to use coaxial feed line for all of the connections, you can't just use plain wire, the video will look abysmal. As I understand it, anything in the 10's of Mhz and above is where you need to start paying attention to layout and termination and such. Such a project would be best done with a real printed circuit board having separate power planes for digital and analog, which gets you into multy-layer PCBs and $$$.
You might be able to get away with just a double sided PCB if it's small and you use the one side as a the ground plane. I'm not sure though, someone else will have to chime in on this one for me.
How would we delay the chips so its not possible for them to have 1 card half hooked up? eg (the delay between switching cards)
The MC14551 automagically employs "break before make" logic for all it's switch elements, ensuring no half hooked in connections. The maxim chip does something similar, no tricky delays and such required.