Questions about equivalents of audio/video and digital/analog.

Jerry Avins wrote:

(snip)

> I believe that's also a borderline area where definitions become 
> smudged. I know that the Russians built a computer with trinary logic, 
> but all the decimal systems I know, whether BCD, excess-three, or 
> something more exotic, encode the numbers on sets of four wires that 
> carry two-state signals. Making a case that that isn't binary opens the 
> door to claiming that hexadecimal is distinct from binary.

I believe that some of the early machines used 10 wires.

Biquinary, with seven wires, one of two and one of five, has
also been used.

In both cases each wire has one of two values, but it isn't very
"binary like".

-- glen

Don Pearce wrote:

(snip)

> No, you haven't. You merely have a signal at a set of discrete levels.
> You need an analogue to digital converter to take each of those
> quantized levels and convert it into a digital word (of 1s and 0s).

> Digital means "represented by digits", not "in discrete voltage
> steps".

Now it is getting complicated.  Once it is quantized it "could"
be represented by digits.  Whether you actually have to do that,
I am not so sure.

I haven't followed quantum computing so carefully, but it might
be possible to do computing on discrete voltage levels that
haven't been converted to digits.   (And note that the usual
representation of a digital signal is by voltages on wires.)

-- glen

Radium's ability to suck so many people into attempting to
answer insane questions is reaching legendary heights.
I hereby nominate him for the Troll Hall of Fame with special
endorsement for use of technical gobeldygook. 

glen herrmannsfeldt wrote:
> Jerry Avins wrote:
> 
> (snip)
> 
>> I believe that's also a borderline area where definitions become 
>> smudged. I know that the Russians built a computer with trinary logic, 
>> but all the decimal systems I know, whether BCD, excess-three, or 
>> something more exotic, encode the numbers on sets of four wires that 
>> carry two-state signals. Making a case that that isn't binary opens 
>> the door to claiming that hexadecimal is distinct from binary.
> 
> I believe that some of the early machines used 10 wires.

With ten neon lamps stacked vertically for each digit at first, then 
Nixie tubes.

> Biquinary, with seven wires, one of two and one of five, has
> also been used.

That was so entrenched that TI's first IC decimal counter could be 
configured as a biquinary device. It had divide-by-two and 
divide-by-five sections.

> In both cases each wire has one of two values, but it isn't very
> "binary like".

It really depends on context. From a circuit viewpoint, I think of 
"binary" as implying a single receiver threshold.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Scott Seidman wrote:

(snip)

> Doesn't "analog" also imply that x(t) exists for all t in range, and not 
> just at nT for all n in range?  Or would people just call that "sampled"? 

Yes, that would be "sampled".  Since analog tends to imply continuous
(non-sampled) it would probably be best to use "sampled analog" for
non-continuous non-quantized data.

-- glen

On Mon, 20 Aug 2007 11:58:32 -0700, "Richard Crowley" <rcrowley@xp7rt.net>
wrote:

>Radium's ability to suck so many people into attempting to
>answer insane questions is reaching legendary heights.
>I hereby nominate him for the Troll Hall of Fame with special
>endorsement for use of technical gobeldygook. 

I vote: aye
-- 
Official website "Jonah's Quid" http://www.jonahsquids.co.uk

"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote in message 
news:E6ednXh1JIkcRlTbnZ2dnUVZ_hynnZ2d@comcast.com...

> How about, Analog implies "infinite" precision in the absence of
> noise, including fundamental quantum noise.

Except that "absence of noise" is a condition which
doesn't exist, even in theory.

ALL systems, digital, analog, or whatever, are limited in
information capacity by (a) the bandwidth of the channel
in question and (b) the level of noise within that channel,
per the aforementioned Gospel According to Shannon.
This is exactly the same thing as saying that there is a limit
to "precision" or "accuracy," as infinite precision implies
an infinite information capacity (i.e., given infinite precision,
I could encode the entire Library of Congress as a single
value, since I have as many effective "bits of resolution"
as I would ever need).

> Note, for example, that an analog current is quantized in units
> of the charge on the electron.

Sure is.  So isn't it a good thing that we don't confuse either
"analog" or "digital" with either "quantized" or "continuous"?

Bob M.

"Scott Seidman" <namdiesttocs@mindspring.com> wrote in message 
news:Xns999294E6D651Fscottseidmanmindspri@130.133.1.4...


> Doesn't "analog" also imply that x(t) exists for all t in range, and not
> just at nT for all n in range?  Or would people just call that "sampled"?

Assuming "t" is time here, no - that would require
that there be no such thing as a sampled analog
representation, and we already have noted examples
of that very thing.

"Analog" != "continuous," even though most commonly
"analog" signals are also continuous in nature.

Bob M.

"Martin Heffels"  wrote ...
> "Richard Crowley" wrote:
>>Radium's ability to suck so many people into attempting to
>>answer insane questions is reaching legendary heights.
>>I hereby nominate him for the Troll Hall of Fame with special
>>endorsement for use of technical gobeldygook.
>
> I vote: aye

I don't mean to imply that there may not be idiot-savants
on the interweb.  Al Einstein himself may easily have been
perceived as a troll if he were online :-) 

"Richard Crowley" <rcrowley@xp7rt.net> wrote in message 
news:5iu86vF3ogf25U1@mid.individual.net...

> I don't mean to imply that there may not be idiot-savants
> on the interweb.  Al Einstein himself may easily have been
> perceived as a troll if he were online :-)

And let's not forget Alfred Nobel's half-brother
Ignatz, the benefactor behind the Ig Nobel prize,
awarded for outstanding contributions to that
very field...;-)

Bob M.