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"There's no such thing as digital", Interesting articles from Audiostream
dhromed
post Jan 10 2014, 19:28
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QUOTE (knutinh @ Jan 10 2014, 18:44) *
It seems that every technological advance made in the last 30 years have been used to give us more crap, more compromise, less reliability. Talk about progress :-)


This reminds me of a tweet. From memory:
QUOTE
"It's the future! Where are my flying cars?" he spoke instantly to an audience of thousands from a device in the palm of his hand

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andy o
post Jan 12 2014, 02:17
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QUOTE (Arnold B. Krueger @ Jan 9 2014, 12:51) *
I read a few of his pieces and decided that he is an entertaining writer but that he either doesn't read his references or is a deliberate liar practitioner of poetic liberties.

Case in point:

http://www.wired.com/medtech/drugs/magazin...t?currentPage=2

"Placebos Are Getting More Effective. Drugmakers Are Desperate to Know Why."

"Beecher's prescription helped cure the medical establishment of outright quackery, but it had an insidious side effect. By casting placebo as the villain in RCTs, he ended up stigmatizing one of his most important discoveries."

He cites:

"The Powerful Placebo"

http://www.jgh.ca/uploads/psychiatry/links/beecher.pdf

Beecher's article's conclusion starts out "When subjective responses, symptoms, are under
study, it is apparent that the high order of effectiveness
of placebos must be recognized."

..and goes on in the same spirit: positive.

No way was the placebo cast as a villain.

I call that taking liberties with one's main reference. Read the articles for yourself and reach your own conclusions. ;-)

I thought, it being Wired, something must have been written about this in the science blogs, and sure enough: http://www.sciencebasedmedicine.org/placeb...ou-think-it-is/

Silberman apparently shows up in the comments, if you're interested what he has to say in his defense.

This post has been edited by andy o: Jan 12 2014, 02:24
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Martel
post Jan 12 2014, 13:13
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QUOTE (knutinh @ Jan 10 2014, 18:44) *
Or my tv channels might not have analog echo and noise (continous problems), but rather there are sudden loud transients (lost packets) or pixelated video. It seems that every technological advance made in the last 30 years have been used to give us more crap, more compromise, less reliability. Talk about progress :-)

DVB-T has many channel configuration options, see the table at the end of the following chapter:
http://en.wikipedia.org/wiki/DVB-T#Technic...B-T_transmitter

It could be configured for better error tolerance at the cost of usable channel bandwidth.

In addition, the digital terrestrial television technologies deployed today are quite dated. DVB-T, for example, does not allow to carry a base high-error-tolerance low-fidelity stream together with a higher definition additional stream (with lower error tolerance). This would allow people with poor signal to still watch some low-fidelity TV instead of a blank screen.

Ultimately, it's a matter of choice how the digital technologies are designed and utilized. It's not the fault of "digital" per se.


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saratoga
post Jan 12 2014, 20:27
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Digital error correction is actually much more robust than older analog schemes. However, as we have built more digital devices, we have used more and more spectrum, requiring that transmissions be squeezed into as little bandwidth and power as physically possible.

If you actually just wanted to transmit 480i video on the old USA VHF channel 2 at 1960s power levels, you could have dependable H.264 video at distances where analog wouldn't even show up. However no one does this because that would waste a large amount of very precious RF spectrum.
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saratoga
post Jan 12 2014, 20:32
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QUOTE (ktf @ Jan 10 2014, 06:59) *
QUOTE (Martel @ Jan 10 2014, 10:02) *
Entirely analog transmission just does not (cannot?) precisely remove/isolate channel noise from information. I don't think there's anything beneficial about that.

Actually it can, but those methods are so 'simple' that most might not call it error correction at first look. Differential signaling (balanced audio cables) is one trick where part of the noise coupled on a line can be easily filtered. It works really well for most noise sources.


You're massively overestimating how powerful those techniques are. Balanced detection has a limited common mode rejection ratio (CMRR) in any practical device. For example, in analog optical systems, obtaining even 30dB CMRR is considered outstanding. Do that on a noisy channel and you have a noise floor of 30dB. In such circumstances some form of digital error correction is essentially mandatory.
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greynol
post Jan 12 2014, 22:43
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Communication Systems Engineering by Proakis and Salehi is a good book on the subject. Some of you should study it or something similar. It would cut down on a lot of the nonsense being said.


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saratoga
post Jan 12 2014, 23:08
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Proakis's text is my go-to reference on discrete time systems, but I think that book is probably well beyond most of the people posting in this thread, and does not go into any detail on the electromagnetic physics needed to understand the performance of analog systems.

The core problem here is that everyone has opinions about analog and digital systems, and for digital they may even be fairly sensible-ish, but to really understand analog you need a graduate level education in EE. Without that it is almost impossible to really understand what is happening and you're just going to get lost in a mess of meaningless arguments about what is and isn't quantized without understanding what it really means.
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UNHchabo
post Jan 13 2014, 04:52
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QUOTE (saratoga @ Jan 12 2014, 14:08) *
...to really understand analog you need a graduate level education in EE. Without that it is almost impossible to really understand what is happening and you're just going to get lost in a mess of meaningless arguments about what is and isn't quantized without understanding what it really means.


Yeah, with my CS degree I only had to take a couple of EE/CE courses, and I couldn't tell if the article was spouting pseudoscience, or just EE knowledge that was over my head.

That is, until I got to this part:

QUOTE
...unless one is planning to use a wireless link, which has not only potential long-term health risks...


... Okay then, I know I can ignore this article entirely. mad.gif


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