Spacewar! (was Re: Laser display...)

From: Eric Smith <eric_at_brouhaha.com>
Date: Sun Feb 20 14:02:49 2005

Sellam wrote about the Magnavox Odyssey game:
> While the design may operate like a digital
> computer,

It doesn't.

> it uses entirely analog techniques to produce the digital
> results.

To some extent it's a matter of semantics. Is a one-shot (monostable
multivibrator) such as an SN74121 an analog device or a digital device?
It uses an RC time constant (analog) to control the pulse width of a
digital signal.

If you consider a one-shot to be a digital device, then most of what
is in the Odyssey is digital. Otherwise, one would have to consider
it to use a mix of analog and digital techniques.

> Everything the box does is a result of analog circuitry.

So now your claiming that AND and OR gates are analog? Most people
would disagree. Though in a sense you're correct, in that all digital
circuits are constructed from analog circuits. Design engineers forget
this at their peril. It's easy to think of them as ideal digital
elements, but they aren't.

Eric
Received on Sun Feb 20 2005 - 14:02:49 GMT