Re:Reverse engineering the Sega Channel game image file format
by phire on Sunday December 08, 2024 @02:52PM
(#42359840)
Yeah, I was wondering how TV-like this channel looked.
It's tempting to wrap it in fake horizontal/vertical blanking so it still looks like a TV signal (and you can send it through existing equipment that's expecting a TV signal). Essentially just Teletext but using every single line.
But what Scientific Atlanta created is much closer to cable internet. The total bandwidth number is notable, each 6Mbit carrier uses 3Mhz of bandwidth, so the two of them add up to 6Mhz, which is how much bandwidth a standard NTSC channel occupies.
I suspect this is because they have rented a single TV channel worth of bandwidth on the Galaxy 7 satellite for disruption to local cable companies.
Splitting into two 3Mhz carriers has the additional advantage of allowing the receiver design to be simpler, it only needs to tune into one at any time.
It's tempting to wrap it in fake horizontal/vertical blanking so it still looks like a TV signal (and you can send it through existing equipment that's expecting a TV signal). Essentially just Teletext but using every single line.
But what Scientific Atlanta created is much closer to cable internet. The total bandwidth number is notable, each 6Mbit carrier uses 3Mhz of bandwidth, so the two of them add up to 6Mhz, which is how much bandwidth a standard NTSC channel occupies.
I suspect this is because they have rented a single TV channel worth of bandwidth on the Galaxy 7 satellite for disruption to local cable companies.
Splitting into two 3Mhz carriers has the additional advantage of allowing the receiver design to be simpler, it only needs to tune into one at any time.