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When Digital Becomes Analog

Ox

Diamond
Joined
Aug 27, 2002
Location
Northwest Ohio
I don't think that I posted this yet, and stumbled accrost it again just now. I found this interesting, so I'm putin' it up now....

April 2017 Modern Machine Shop magazine

Digital / Analog



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Think Snow Eh!
Ox
 
Thought provoking.

Tom

No, it is not, it just Nyquist. The only controversy ever existed in the digital domain is the phase shifts caused by brick wall filters. Look at it pragmatically, any waveform that can be described as a function can be passed through a Laplace of Fourier transform and made to be a finite S/N and bandwidth spectrum. That is where Nyquist comes in. When we get beyond the limits of human perception digital and analog becomes indistinguishable.

dee
;-D
 
No, it is not, it just Nyquist. The only controversy ever existed in the digital domain is the phase shifts caused by brick wall filters. Look at it pragmatically, any waveform that can be described as a function can be passed through a Laplace of Fourier transform and made to be a finite S/N and bandwidth spectrum. That is where Nyquist comes in. When we get beyond the limits of human perception digital and analog becomes indistinguishable.

dee
;-D

That's not the intent that I gathered from the article. It's the human perception of the information. However the information is processed, its the same information. Actually, if you get to the level of quantum mechanics, everything is digital. The latency of our brains and mechanical instruments causes the digital information to be integrated to analog. My processor brain is a Z80 in a world now of supercomputers. I can process analog information faster than digital. An example to me is a Simpson meter to a Fluke digital. The fluke is much more accurate but I get information more rapidly from the Simpson.

Tom
 
That's not the intent that I gathered from the article. It's the human perception of the information. However the information is processed, its the same information. Actually, if you get to the level of quantum mechanics, everything is digital. The latency of our brains and mechanical instruments causes the digital information to be integrated to analog. My processor brain is a Z80 in a world now of supercomputers. I can process analog information faster than digital. An example to me is a Simpson meter to a Fluke digital. The fluke is much more accurate but I get information more rapidly from the Simpson.

Tom

Tom, you got this exactly backwards. There is no such thing as digital. The universe is analog. Digital is nothing more than interpretation.
 
Tom, you got this exactly backwards. There is no such thing as digital. The universe is analog. Digital is nothing more than interpretation.

And analog is not?

Lets take a simple case. Electrons in orbit. They can only exist is defined shells. To support your argument, take the case of photons. Depending on the way they are examined, they are either digital or analog, particle or wave functions. Schrodinger equation.

We are now in the realm of metaphysics. If you get right down to it, we don't know what it is. As you say, its only our interpretations. Only God knows.

Tom
 
Somehow I think something went overhead as I must'a been lookin' down... :scratchchin:


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Think Snow Eh!
Ox
 
I will go back to my original comment.

Thought provoking.

Tom

Everything goes back to this

Nyquist–Shannon sampling theorem - Wikipedia

When the errors are no longer perceptible the results are no longer distinguishable. I had to spend a few semesters being tortured by the math, and I listened to a lot of digital music and analog music to understand the real world implications.

dee
;-D
 
Everything goes back to this

Nyquist–Shannon sampling theorem - Wikipedia

When the errors are no longer perceptible the results are no longer distinguishable. I had to spend a few semesters being tortured by the math, and I listened to a lot of digital music and analog music to understand the real world implications.

dee
;-D

I guess I don't have any idea how that fits into what Ox was pointing out which is that digital displays are now emulating analog.

Tom
 
I guess I don't have any idea how that fits into what Ox was pointing out which is that digital displays are now emulating analog.

Tom

When you digitize a signal, you have the choice of representing it as the value of the samples, a graph, needle or a wave. The question becomes of fidelity to the original signal. If you digitize it then Nyquist is very relevant. if you just plot the original signal, sampling theory is not a consideration. It is a usability problem whether the display is the numerical representation of the measurements or some other visual.


dee
;-D
 
When you digitize a signal, you have the choice of representing it as the value of the samples, a graph, needle or a wave. The question becomes of fidelity to the original signal. If you digitize it then Nyquist is very relevant. if you just plot the original signal, sampling theory is not a consideration. It is a usability problem whether the display is the numerical representation of the measurements or some other visual.


dee
;-D

I understand all that. I too have had experience on the subject. But what you are referring to is not the point of the article.

Until recently (1960-1970's) instrumentation and displays for such as voltage, current, dial indicators and so forth were all analog. Then came along digital displays which used a string of digits instead of pointer swings. For fast changing conditions, these displays are hard to interpret. So the makers are trying to return to analog type of displays but with the accuracy and precision of digital. A case in point is the speedometer in your car. Much easier to read than a numerical display.

How the analog information is converted into digital is the concern of the instrument makers not the guy holding the micrometer. But he does care about how the information is presented to him. It is only been recently that graphics were cost effective and had the resolution of imitate say, a D'Arsonval meter movement.

Tom
 
Everything goes back to this

Nyquist–Shannon sampling theorem - Wikipedia

When the errors are no longer perceptible the results are no longer distinguishable. I had to spend a few semesters being tortured by the math, and I listened to a lot of digital music and analog music to understand the real world implications.

dee
;-D

I think you are missing the point of the article.

The article was discussing the fact that humans can gather information, process, and interpret the information in an analog signal much easier than a digital expression of it.

Nyquist has nothing to do with this portion of the interpretation as the issue is in the display not the processing of the signal.

Humans are pretty good at sensing 1st and 2nd derivatives and maybe even 3rd order derivatives in special circumstances. Same goes for integrals.

Part of this gets back to that we are surrounded by the universe which we experience in 3 directional dimensions plus a 4th, time which is sort of different. For us to get the most information from a signal, we need to experience it in a 4 dimensional matrix. Adding more signal dimensions beyond the 4 becomes rather meaningless since it is difficult for us to comprehend 5 dimensional objects.

The article was trying to make the point that a digital display of the information does not communicate to us as humans, the depth of information that is in the signal.

You used an audio signal for an example. The issue with an audio signal is that if we displayed it in realtime as say just frequency, it would have little meaning to us even if we could see and process the numbers screaming by. It is only when we get to hear the frequency and volume with the integrals and the derivatives to at least the 2nd and 3rd orders does it have much significance to us.

This gets back to the underlying reason why the automotive industry has went to the effort they have in dashboard design and the trend for striving to emulate an analog display on top of the digital signal processing.
 
And analog is not?

Lets take a simple case. Electrons in orbit. They can only exist is defined shells. To support your argument, take the case of photons. Depending on the way they are examined, they are either digital or analog, particle or wave functions. Schrodinger equation.

We are now in the realm of metaphysics. If you get right down to it, we don't know what it is. As you say, its only our interpretations. Only God knows.

Tom

You make a good point.

The Universe does indicate that there is a level of granularity which occurs at the planck length and gets back somewhat to Schrodinger's Paradox. There is a point in which the cat is always either fully dead or fully alive.

The cat's status is a binary status however most things at the quantum level are not binary even though they are granular. Your example of the photon and electrons in their shells are examples of this.

The issue involves the problem of trying to represent mathematically a binary state across multiple dimensions and we aren't even sure of the number of dimensions.

Add to this the implications of the double slit experiment in which the very presence of the observer changes the outcome indicates that your comment of "God only knows" as being much more correct than we really appreciate.
 
Digital is about the wrongest word one could have introduced to the binary-numeric scheme. The latin word digitus means finger, our fingers full of nerves sensitive to pressure, warmth, and more. The idea was to illustrate counting by the fingers. Our nerves don’t work analog, brain partly does, and logical is again a totally miscaptured expression. The greek word logos means word, something speakable, language-wise. Alog and analog were helplessly stacked upon. What lacks with such contemplations is the human will.
 
I don't think that I posted this yet, and stumbled accrost it again just now. I found this interesting, so I'm putin' it up now....

April 2017 Modern Machine Shop magazine

Digital / Analog

Think Snow Eh!
Ox

To me a bit like discussing apples and pears. Two different things. I remember at one time the endless and pointless discussions as to which was the more important. QA or QC. Personally I know which I prefer.

analogue

adjective

1. relating to or using signals or information represented by a continuously variable physical quantity such as spatial position, voltage, etc.
"analogue signals"
(of a clock or watch) showing the time by means of hands or a pointer rather than displayed digits.

noun

1. a person or thing seen as comparable to another.
"an interior analogue of the exterior world"

digital

adjective

1. (of signals or data) expressed as series of the digits 0 and 1, typically represented by values of a physical quantity such as voltage or magnetic polarization.
relating to, using, or storing data or information in the form of digital signals.
"digital TV"
involving or relating to the use of computer technology.
"the digital revolution"

2. (of a clock or watch) showing the time by means of displayed digits rather than hands or a pointer.

I have two wrist watches. One analogue - I can see the time at a glance. The other is digital and I see not only the time but the day and date. I don't wear them both at the same time but normally I prefer the analogue to the digital.

As far a measuring instruments go then digital :) They normally have more "options" than analogue.
 








 
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