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

"Bob Myers" <nospamplease@address.invalid> wrote:
>"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.

Apparenlty Claude Shannon didn't agree with you on that.

Part I of "A Mathematical Theory of Communications" carries
the title "Discrete Noiseless Systems".  Section 1 of that
part is titled "The Discrete Noiseless Channel".  It turns
out that is a very important theoretical model.

>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"?

Backwards.

-- 
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

On 8/20/07 11:58 AM, in article 5iu6iuF3qsf7aU1@mid.individual.net, "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.
> 
> 

He does have a knack for getting into esoteric points before having an
understanding foundation.  Not insane, but all over the map.

I'll vote for your candidate, in any case.

On Aug 20, 12:11 am, nos...@nospam.com (Don Pearce) wrote:

> analogue - a continuous representation of the original signal
> sampled - a representation of the signal at discrete time points
> quantized - a sampled signal, but with the possible levels constrained
> to a limited set of values
> digital - a quantized signal, with the individual levels represented
> by numbers

I agree with your list.

That means the device in the link below is neither analog nor
digital.

http://www.winbond-usa.com/mambo/content/view/36/140/

I'd like to see a purely-analog device which can record, store, and
playback electric audio signals [AC currents at least 20 Hz but no
more than 20,000 Hz] without having any moving parts [except of course
for the diaphragms present in the microphone and speaker and the
electrons that make up the electric signal] and without any amount of
sampling.

The CCD is out of the question as it uses sampling.

Radium <glucegen1@gmail.com> wrote in news:1187655470.606369.55890
@j4g2000prf.googlegroups.com:

> That means the device in the link below is neither analog nor
> digital.

Or more accurately, both analog and digital.

-- 
Scott
Reverse name to reply

Scott Seidman <namdiesttocs@mindspring.com> wrote:
>floyd@apaflo.com (Floyd L. Davidson) wrote in
>news:87mywlki1d.fld@apaflo.com:
>
>> Sheesh!  That *is*, by definition a digital signal.
>>
>
>Funny, that's just what my D/A converters put out, and the spec sheets
>claim they're putting out analog signals.  Perhaps I should return them.

Your D/A converter puts out what is called
"quasi-analog".  It's actually a digital PAM signal, not
an analog signal.

You can easily make it is a close approximation of the
original (with quantization distortion added), however,

But once you do that (by sending it through almost any
kind of an analog channel) it truly becomes "analog", in
the sense that you can no longer recover information or
use it as a digital signal.

-- 
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

nospam@nospam.com (Don Pearce) wrote:
>On Mon, 20 Aug 2007 13:33:34 -0800, floyd@apaflo.com (Floyd L.
>Davidson) wrote:
>>>>
>>>>A "quantized analogue signal" is digital by definition.
>>>>
>>>
>>>No, you haven't. You merely have a signal at a set of discrete levels.
>>
>>Sheesh!  That *is*, by definition a digital signal.
>>
>If you put that signal through an analogue amplifier, it will be
>amplified. That makes it an analogue signal.

It wasn't analog until you ran it through an analog amplifier.

>If you want to amplify a
>signal in the digital domain, you must perform maths on the numbers.
>Can you really not see the difference?

Non-sequitur.  When you quantize an analog signal you
have a digital signal.  Just as it is possible to
convert an analog signal to a digital signal, it is
possible to convert a digital signal to analog.

One way to do it is to generate a digital PAM signal and
pass it through an analog channel.

>>>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".
>>
>>Bullshit son.  Look it up.  I've provided you with
>>quotes from an authoritative reference, twice now.  You
>>don't have to take my word for it, that *is* the agreed
>>technical definition of the term.
>
>Sorry, but you are wrong. And any reference you have found that makes
>such a claim is not authoritative; it is also wrong.

As if *you* are an authority!  Bullshit son.

The NTIA is an authority, and MilStd specifications are
also authoritative.  That is the reason I cited them.
And the *fact* is that you have not and cannot cite any
authoritative standards body that does not agree with
them.

-- 
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

On Aug 20, 8:47 am, "Bob Myers" <nospample...@address.invalid> wrote:

> You can also
> reduce the temporal frequency in the case of motion video.

That's what I was talking about. Reducing the temporal frequency of
the video w/out low-pass filtering or increasing the length of the
movie.

On 8/20/07 5:17 PM, in article
1187655470.606369.55890@j4g2000prf.googlegroups.com, "Radium"
<glucegen1@gmail.com> wrote:

> On Aug 20, 12:11 am, nos...@nospam.com (Don Pearce) wrote:
> 
>> analogue - a continuous representation of the original signal
>> sampled - a representation of the signal at discrete time points
>> quantized - a sampled signal, but with the possible levels constrained
>> to a limited set of values
>> digital - a quantized signal, with the individual levels represented
>> by numbers
> 
> I agree with your list.
> 
> That means the device in the link below is neither analog nor
> digital.
> 
> http://www.winbond-usa.com/mambo/content/view/36/140/
> 
> I'd like to see a purely-analog device which can record, store, and
> playback electric audio signals [AC currents at least 20 Hz but no
> more than 20,000 Hz] without having any moving parts [except of course
> for the diaphragms present in the microphone and speaker and the
> electrons that make up the electric signal] and without any amount of
> sampling.
> 
> The CCD is out of the question as it uses sampling.
> 

Which means you still do not understand basics.

Scott Seidman <namdiesttocs@mindspring.com> wrote:
>floyd@apaflo.com (Floyd L. Davidson) wrote in
>news:87zm0mjrfy.fld@apaflo.com:
>
>>>quantized - a sampled signal, but with the possible levels constrained
>>>to a limited set of values
>>
>> That is by definition a digital siganl.  As soon as the possible values
>> are "constrained to a limited set", it is by definition digital data.
>>
>>
>
>Wouldn't this make the output of a D/A converter digital by definition?

It is in fact!  It's a digital PAM signal.  Indeed, v.90 modems
make use of it.

However, just as you can convert an analog signal to digital, you
can indeed convert digital to analog.  One method is to produce a
digital PAM signal and run it through an analog channel.  What
you get directly from the D/A is technically called "quasi-analog"
because of that.

-- 
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com

nospam@nospam.com (Don Pearce) wrote:
>On 20 Aug 2007 21:42:18 GMT, Scott Seidman
><namdiesttocs@mindspring.com> wrote:
>
>>floyd@apaflo.com (Floyd L. Davidson) wrote in
>>news:87zm0mjrfy.fld@apaflo.com:
>>
>>>>quantized - a sampled signal, but with the possible levels constrained
>>>>to a limited set of values
>>>
>>> That is by definition a digital siganl.  As soon as the possible values
>>> are "constrained to a limited set", it is by definition digital data.
>>>
>>>
>>
>>Wouldn't this make the output of a D/A converter digital by definition?
>
>It certainly would.  But apparently there are those that can't see the
>difference between a limited set of values, and a set of numbers
>describing those values.

You don't appear to understand that the limited set of values makes
it digital, by definition.  PERIOD.

Of course if you then run that digital PAM signal through virtually
any analog channel, it no longer has a limited set of values...

-- 
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)              floyd@apaflo.com