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Originally Posted by Eric H
And how about High Definition? Drill about 1000 holes in the disk and away you go!
Seriously, could that work?
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I think this doesn't work. If you want to get a picture with 1 inch width you have to create a Nipkow disk with 27 feet diameter! This disk will be so heavy that you need a car's motor to drive it. Or if you use a 12 inch diameter disk, the picture width is .037 inch and you need a microscope to watch TV! Another problem is the loss of light. On a 32 line disk, 99.9 percent of the light will be absorbed by the disk surface. And now you can calculate how many light you need to see a visible picture on a 1000 line disk.
32 lines a a good compromiss between disk width, picture resolution and loss of light. But much more interesting for me are the experiences with the picture quality. 32 lines are not HDTV. But for a lot of video material it is good enough to recognize what happens on the screen. News broadcasts are not suitable for narrow bandwidth television. But music videos are, tv shows are suitable too. Make your own experiences. Here is an example of a NBTV video with 32 lines (1.1 MByte, I will keep it on the server for the next week):
http://bs.cyty.com/menschen/e-etzold/NBTV_Example.zip
Download it and if you have no scanning disk monitor use a sofware player (116 KByte):
http://www4.tpgi.com.au/users/gmillard/NBTVViewer.zip
The first color tv with a scanning disk was realized by John L. Baird in the 1920s. He operated with a two color system (red-orange and blue-green).
Th whole discussion asround NBTV is in its core a discussion about what is good enough for video broadcasting. For decades we thought that the only answer is to increase the number of lines on and on. But since videos were playable on a PC with minimum resolution (remember the days of Windows 3.1 and the first AVI videos as large as a postage stamp), people discovered that low definition video enjoys the watchers too. This is the re-discovering of NBTV which lead back to the times of Nipkow disks and mirror drums.