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Old 14th Sep 2018, 10:51 am   #41
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Default Re: The Persistence of Analogue

Brigham has it about right, I think (post 34). Opportunistic sales hype; nothing more.
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Old 14th Sep 2018, 2:12 pm   #42
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Default Re: The Persistence of Analogue

The thread title makes me think about an oil painting of a bleak scene with a sort of cuboud structure and a very odd tree with melted digital watches draped over them.



A sort of surrealist commentary on how long digital thingies stay current for.

David
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Old 14th Sep 2018, 2:42 pm   #43
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Default Re: The Persistence of Analogue

Brigham is indeed correct.

I remember some ads promoting DAB that proclaimed the listener would hear stations in 'digital quality'.

Meaningless but impressive.
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Old 14th Sep 2018, 3:41 pm   #44
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Default Re: The Persistence of Analogue

I think even the most hardened devotees of 'vinyl' accepted that the digital encoding, storage and reproduction probably represented a step forward. Hence 'digital' became a byword for top-notch audio quality, and the word became more widely associated with good quality. Since then, however, digital technology has been hijacked by ruthless cutting of bandwidth and cost to the point where the phrase "digital rubbish" is frequently heard, especially when describing cheap electronic consumer goods.
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Old 14th Sep 2018, 4:30 pm   #45
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Default Re: The Persistence of Analogue

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I think even the most hardened devotees of 'vinyl' accepted that the digital encoding, storage and reproduction probably represented a step forward.
I was one of those people, Phil, and CDs were talked about reverently back in the '80s when we dumped our vinyl and checked out the few outlets in town who were selling CDs, eagerly building up a collection of 1s and 0s on shiny-backed plastic discs that 'would never wear out...'

One of the chaps at work knew someone who knew someone who could get Philips CD160 players at cost-price, and the take-up order was huge! In fact, there's still one on site here.

But things move in circles, and the young are naturally curious about vinyl, film, cassettes that their forebears used, and some of them found they like them.

Go, hipsters!

I might add that I have got several younger staffers at work interested in black-and-white film photography to the extent that they have gone out and bought film cameras off eBay: we might even get our works club darkroom going again.
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Old 14th Sep 2018, 7:43 pm   #46
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Talking Re: The Persistence of Analogue

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I have seen domestic light switches described as "digital". As far as I was aware, apart from dimmers, light switches have always been digital?
Since domestic light switches are operated by fingers - a.k.a. 'digits' - so yes, that sounds about right!

Al.
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Old 14th Sep 2018, 8:03 pm   #47
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Default Re: The Persistence of Analogue

Just so long as we take the whole analogue/digital thing with a sense of humour, we'll be alright.

It's the people without the sense of humour who are dangerous!

One quip I came out with some time ago: "Here, mate, this digital camera you flogged me... all the critical bits are analogue! I want me money back!"

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Old 14th Sep 2018, 8:31 pm   #48
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Default Re: The Persistence of Analogue

Cameras are a good example. We all know that the resolution of a good quality fine-grained 'analogue' photograph can exceed that of an indifferent digital image. I am frequently amazed at the quality of some very old monochrome photographs. But we'd surely miss digital tools like Photoshop for removing the creases and stains!
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Old 14th Sep 2018, 9:02 pm   #49
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Default Re: The Persistence of Analogue

Digital allows the instant 'real-time' debate about how good or bad it is. Otherwise it's letters to the editor!
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Old 14th Sep 2018, 9:55 pm   #50
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Default Re: The Persistence of Analogue

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Cameras are a good example. We all know that the resolution of a good quality fine-grained 'analogue' photograph can exceed that of an indifferent digital image. I am frequently amazed at the quality of some very old monochrome photographs. But we'd surely miss digital tools like Photoshop for removing the creases and stains!
Ah. But is photographic film analogue? For simplicity, thinking black and white only, I have generally believed that it contains many many microscopic crystals of silver halide. When irradiated by photons, a few atoms are converted to metallic silver; developing causes the whole crystal to become silver; fixing removes the unconverted crystals. Because the crystals are so minute, and distributed through the emulsion, and because photons are discrete, there is a probability that a particular crystal will encounter a photon, approximately proportional to the exposure to light.

Thus, ultimately, each crystal is either 'off' or 'on' and it's only because there are so many of them that it appears continuous, both space-wise and darkness-wise.

Same goes for our eyes - retinas are covered with discrete sensors, each sensor generating an output or not (I recall reading that a retinal rod cell registers an output if hit by more than 50 photons in a millisecond, which is pretty awesome). So resolution of our eyes is not infinite, but is 'good enough' to appear so; and with the minute scanning movements that eyes make, there's even a bit of 'dither' allowing interpolation to maybe an extra couple of bits, spatially! My personal conclusion is that God exists, and He is a design engineer...

I suppose the exposure and focussing mechanisms are also semi digital - they are activated by muscles which are composed of discrete cells, but the contraction of each muscle cell is dependent on how often it gets a triggering impulse - and as time is (as far as we know) not quantised, the strength of a muscle's contraction can be varied by nerve impulses with a truly infinite mark:space ratio!
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Old 14th Sep 2018, 10:25 pm   #51
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Default Re: The Persistence of Analogue

No. Humans are design engineers, and humans invented gods; around a thousand different incompatable and mutually exclusive gods since religions were invented. Theists believe in only one of these gods; atheists just go one god further!

Human and animal senses evolved to the point that they are good enough for the purpose, and should be considered as imperfect yet adequate analogue transducers.
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Old 14th Sep 2018, 10:36 pm   #52
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But are our senses analogue? They seem analogue, but it could be that they are digital with resolution just a bit too good for us to be conscious of it.

Taste and smell are probably the hardest to assess. Hearing, in intensity and pitch is probably discrete, but direction is virtually analogue as we can do direction-finding to essentially arbitrary precision. We could probably argue the toss about sight. Touch is quite complex; we can distinguish between pressure, temperature, and loads more!
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Old 15th Sep 2018, 8:46 am   #53
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You're right there. All our 'sensors' have evolved to work by quantizing the inputs to a level of resolution that's adequate. The result appears analogue because the granularity is so small. 'Modern' technologies like film, TV and audio all exploit the weaknesses in our senses so that we don't notice the missing information in MP3 audio coding, for example, or we see a sequence of still images 25 times a second as a continuous moving image.

It strikes me that most 'analogue' electronic systems also have limits to their resolution, such as the uniformity of density of magnetic particles on tape or (as you discussed) grains of silver on film. As long as the granularity exceeds that of our ears or eyes, all looks and sounds fine! When imperfections such as noise, limited frequency response and so on exceed a certain low level, we start to notice them.
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Old 15th Sep 2018, 9:53 am   #54
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Default Re: The Persistence of Analogue

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Originally Posted by Phil G4SPZ View Post
You're right there. All our 'sensors' have evolved to work by quantizing the inputs to a level of resolution that's adequate. The result appears analogue because the granularity is so small. 'Modern' technologies like film, TV and audio all exploit the weaknesses in our senses so that we don't notice the missing information in MP3 audio coding, for example, or we see a sequence of still images 25 times a second as a continuous moving image.

It strikes me that most 'analogue' electronic systems also have limits to their resolution, such as the uniformity of density of magnetic particles on tape or (as you discussed) grains of silver on film. As long as the granularity exceeds that of our ears or eyes, all looks and sounds fine! When imperfections such as noise, limited frequency response and so on exceed a certain low level, we start to notice them.
Also keep in mind that effects such as intermodulation can create sensory artifacts from frequencies which are beyond our senses ability to directly resolve.
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Old 15th Sep 2018, 9:56 am   #55
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Default Re: The Persistence of Analogue

...and we can perceive quantum effects such as diffraction patterns in the famous double slit experiments.
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Old 15th Sep 2018, 10:27 am   #56
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...effects such as intermodulation can create sensory artifacts from frequencies which are beyond our senses' ability to resolve directly...
That's interesting. I've often wondered whether it's possible to hear the beat frequencies arising from large numbers of bats flying together, as often depicted in films. I've never experienced it myself, and have sort-of concluded that the mass and inertia of the eardrum are just too large to move at anything above 20kHz, as the mixing would have to occur inside the ear rather than in the air outside it, but I'm willing to be proved wrong!

Would looking at two ultraviolet sources with a frequency difference in the visible range give rise to a visible effect?
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Old 15th Sep 2018, 10:54 am   #57
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Default Re: The Persistence of Analogue

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Would looking at two ultraviolet sources with a frequency difference in the visible range give rise to a visible effect?
On the same sort of principle as hearing 'bat beats', probably not. As I understand it, the human retina is fairly sensitive to (near) UV, but is protected by the filtering effect of the cornea. Apparently, if the cornea is removed, as sometimes happens when there is a necessary delay during cataract surgery, the patient is able to see UV directly. Although I haven't checked, I'd imagine that enough spread-spectrum UV reaches us regularly for any intermodulation effect to be well known should it occur.
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Old 15th Sep 2018, 2:23 pm   #58
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Default Re: The Persistence of Analogue

Human perception depends on neurons to transmit the signals from the 'sensors' to the brain for analysis.

Neurons are a bit like thyratrons: they have a 'trigger' potential which needs to be reached before the neuron fires and 'saturated' (so transmitting the impulse down the chain to the next neuron) followed by a 'recovery' period during which the various neurotransmitter chemicals in the synapse are regenerated.

A neuron cannot reliably be 'partially' fired - once activated it 'goes all the way', just like a thyratron.

So essentially they're a bit like a Schmitt-Trigger-monostable! And Digital!

This is important - the need to reach the 'trigger' potential before firing provides a kind of protection against low-level crosstalk between the bundles of adjacent neurons that make up a nerve (think of it like a 'squelch' control) while the need for the recovery-period before a neuron can activate again provides a finite limit to the number of impulses in any unit of time that the brain receives, preventing it from having a 'buffer overrun'.
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Old 15th Sep 2018, 4:17 pm   #59
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Default Re: The Persistence of Analogue

Quote:
for any intermodulation effect to be well known should it occur.
Optical non linearity (which you need for intermodulation/mixing etc.) only happens a high power levels, big enough to zap an eye in an instant.
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Old 15th Sep 2018, 11:35 pm   #60
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Default Re: The Persistence of Analogue

Rent #46, I did once see a patent for a light switch (for operation by the fingers in the usual way) whose title was "Digitally-operated switch". It would have been around 1980.

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