What exactly is digital anyway?

Hi, Mr. Terrell. I was trying *not* to define anything.

Digital ICs *are* digital, except when they're not. ;-)

Cheers Chris

They're not. They're electrical circuits fabricated in monolithic chunks of silicon, which are designed for the purpose of manipulating information encoded in digital form as an electrical signal. But it's a whole lot simpler just to use the shorter, if somewhat inaccurate, label of "digital IC."

Bob M.

No, I pray to differ. There are definitely digital ICs - there are ICs that are so digital, that they could be damaged by being driven with an analog signal. And the output is snap-action, which practically defines digital.

I think that would be the operative word - snap-action. (cf. light switch ;-) )

Cheers! Rich

I realize that, but I'd like to see you implement a modern computer operating in a linear, analog mode.

As I said earlier, using the analog representation of information is better for some things; the digital representation is better for others. And you can certainly design circuits that are optimized (sometimes very strongly) for one vs. the other. But it's still all just electricity.

Bob M.

;-) )

OK, so what exactly is it, then, that makes a particular IC (or circuit in general) "digital"? And apparently, there's also some way to measure "degree of digitalness," else we couldn't speak in any sensible way of "ICs that are SO digital..." - what is that measure?

You've suggested that "snap-action" is the operative or defining word here, in terms of what "digital" means - to me, what that seems to be saying is that you feel that "digital" is characterized by rapid changes between discrete states. But is such behavior really exclusive to "digital" systems? MUST it be? If it is, and I were to show you a scope trace of, say, a video signal representing a gray-scale bar pattern, and didn't identify it or give you any other context - would you as the result of this definition assume that you were looking at a "digital" signal?

Please keep in mind that I'm not out to change anyone's usage of terms like "digital ICs" or such - that's way too big a windmill to tilt at. But I think it IS interesting to think about our assumptions in these sorts of things, every so often.

Bob M.

I'm not arguing with you, Bob, merely pointing out that most people would freak if you tried to explain to them that their new digital toy is really plain old analog, operating in the digital domain.

OK - although I'd say it even a bit differently. Their new toy isn't "plain old analog, operating in the digital domain." These two are not opposites of one another, nor is it true that "all that is not digital is analog," or vice-versa. (Power engineering, for example, deals with electrical circuits which are neither - there is no information being conveyed, and so nothing is represented either in analog or digital form. It may be "continuous," and it might in some cases involve things which are "linear" - but neither of these is really the same as "analog." At least not from the perspective I'm trying to argue for here.

Bob M.

If you still would have any brain cells left you would take a peek at this group's name and (probably not) realize the context.