Stephen wrote:With all the different schemes and proposals for NBTV, I am wondering what everyone thinks "narrow-bandwidth" TV really means in terms of bandwidth. When I think of alternate schemes that might provide higher resolution, frame rate or colour, I personally regard it as anything that fits in a high fidelity audio channel, say 20 kHz, but I can imagine that there may be a wide range of opinion on this.
In my past life I've programmed the Atari 2600 video game computer (a 1977 machine) that is fun in the same way that NBTV is fun. The fun is imposing some limitations upon what you can do, and then seeing if you can make things happen. On the Atari, for example, there are some immutable limitations, which everyone must adhere to -- but there are also some variables that can be changed (eg: the amount of RAM, the ROM size, etc).
Now the Atari field has its purists -- those that feel that unexpanded base cartridges should be used (that is, 4K ROM, no extra RAM). This is the fundamental original configuration that the early games used. I was a purist, and pushed the envelope as much as I could. But after a while, I realised the envelope was pushed as far as it would go.
But there were interesting things one could do if one relaxed the self-imposed boundaries just a little bit. What can be done with a little more RAM, for example. Or a much larger ROM, but the same RAM limitations. These sorts of forays into side-fields which might upset the 'purists' are what made it all fun, once one had mastered the basic configuration.
I see an analogy with programming the Atari 2600, and developing mechanical Television systems. It's probably the same in many hobbies. The purists would select 10kHz. They'd also select 30 lines, and having the outermost lines more widely spread.
But it's not about being totally pure. That is but one (valid) part of this hobby. There will be those who want to explore in various directions (for example, the addition of colour piggybacking on the 'standard' club signal, or stereo... or you name it). So I see a 20kHz bandwidth being just as valid as 10kHz. And I see (say) 500kHz just as valid. There won't be many people interested in using 500kHz -- because (for one thing) it would be 'too easy'. Half the fun, as I have found with the Atari, is imposing limitations upon what resources can be used, and then developing something within those limitations.
For me, NBTV is about technique. I love the way that a time-based interaction between a spinning disc with holes in it and a pulsating single light source forms an image! And I love it even more that this was being developed 80 years ago! Yes, I happen to be using LEDs, getting my information from the Internet, using a debugging tool that is light years ahead of what was available then... and my Nipkow disc was cut by a laser. But the fundamental WAY it works is the same as it was back then. Spin a disc with holes at exactly the right speed in front of a light source.
THAT is what NBTV is to me. I don't particularly care if I have a higher bandwidth, more scanlines, or if I'm using a spinning mirror drum instead of a disc with holes. For me it's about the techniques that were historically used at the dawn of television. I think that all of these early methods (including, if we must, CRTs) are perfectly valid claims to NBTV and bandwidth is, in my opinion, just an un-necessary and arbitrary division that's just one of those self-imposed limitations of which I wrote earlier.
Rather than narrow-band television (which is really just a consequence of the technology available back then), I tend to think of what I'm interested in as 'Historical Television' which encompasses techniques, not bandwidth
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