Re: [midatlanticretro] Narrow Bandwidth Computer Terminal project
- HI Joe:
The main issue is going to be synchronization. The mechanical TV
system used spinning disks at the camera, and another at the receiver.
Early receivers had a knob to adjust the disk motor's speed. Once
the receiver's disk was spinning at the same speed as the camera's, then
you'd have a good "non-drifting" image.
Today's TV and video monitor scan speeds are so much faster, that you
would probably have to spin the disk at a very high rate, or use some
sort of electronic system to make the mechanical disk spin at some
whole number fraction of the scan rate.
32 lines of resolution is a pretty crude video picture.
73 de Ray
On May 26, 2008, at 7:10 PM, Joe Giliberti wrote:
> I've come up, at this point, with a (semi) realistic VCF plan. It
> involves constructing an electromechanical video display, such as
> those used in television research in the 1920's and 1930s, and
> somehow, using it as a display terminal for a computer.
> As narrow bandwidth TV works, it uses an audio signal to flash a
> light, which shines through the holes around the circumference of a
> Nipkow disk. As the disk spins faster and faster, at around 750 RPM
> for a 32 hole disk, the lines sync up, and you get a picture,
> usually maginified by a lense, like one from a viewgraph projector.
> The trick is, I have no idea on how to convert, lets say, a
> composite video output, to the light flashes of an LED behind the
> disk. How would one go about doing this?
- A couple of months back, there was a thread about EPROM programmers
suitable for classic systems. While the Willem programmer was one of the
recommended models, I wasn't too keen on the USB requirement. Another
recommendation was the Data I/O 29B, a standalone unit which can be
connected via RS-232 port to a system or terminal. I started keeping an
eye on the Ebay offerings, and finally picked up one at a reasonable
It came with the following adapters:
910-1521 Calibration Extender
If I'm reading things right, I have the right adapters to do 2764s and
the like. I'm anxious to see if I can program a TurboROM or a KayPLUS ROM
for my Kaypro 10. :-)
Mike Loewen mloewen@...
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
- The 29 is a great programmer. Used them at many jobs in the 80s. I don't rememberthe adaptor model numbers, but the 29 could program just about anything with theright adaptor. I was usually doing 2708s, 2716s, and 2732s.You got yourself a good piece of equipment.Speaking of which, it's time to head into the basement and burn a new EPROM formy S-100 machine...BobOn May 28, 2008, at 6:58 PM, Mike Loewen wrote: