John Curl's Blowtorch preamplifier part II - Page 4837 - diyAudio
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Old 13th February 2014, 04:11 AM   #48361
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The modern definition of chaos implies emergent properties, a "structure" within the process observed. True randomness closely observed includes only more randomness on all scales, turtles all the way down.

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Chris
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Old 13th February 2014, 07:23 AM   #48362
RNMarsh is offline RNMarsh  United States
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Quote:
Originally Posted by zapnspark View Post
Some of these types of rounding errors had nasty consequences:

Computer Arithmetic Tragedies page of Kees Vuik

Cheers,

ZAP
And, the processors do this in-flight ! The supercomputers at LLNL often run over night at their max speed doing calculations for hours on codes. The end results may be just a few digits change or a few added decimal places. But it must give the same number every time the calc are done. In the case, i decribed, the slower machine was more consistant but the researchers could not get the extra places they needed.

THx-RNMarsh

Last edited by RNMarsh; 13th February 2014 at 07:26 AM.
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Old 13th February 2014, 10:58 AM   #48363
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Old 13th February 2014, 11:17 AM   #48364
DF96 is offline DF96  England
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A simulation with rounding errors could be considered chaotic. It may be attempting to simulate a chaotic system. These two systems, reality and simulation, may show different chaotic behaviour as the simulation is not the same as the real system.
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Old 13th February 2014, 11:28 AM   #48365
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Quote:
Originally Posted by zapnspark View Post
Some of these types of rounding errors had nasty consequences:

Computer Arithmetic Tragedies page of Kees Vuik

Cheers,

ZAP
Wow! I would have been rich if it wasn't for rounding errors

Jan
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Old 13th February 2014, 04:39 PM   #48366
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Hey jan..

Still workin the article.

Had to go through most of the IR hexfet line to characterize the thermal resistance of their products. I'm finding some really interesting things.

jn
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Old 13th February 2014, 05:00 PM   #48367
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Which is then down to the particular implementation of Spice, how many bits are used for floating point. Nice thing with computing, is that one can always add more grunt when needed - downside is that results take longer to come out, but this is an issue that steadily improves, year by year ...
No one would bother with less than 64 bit floats about -300dB rounding floor.
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Old 13th February 2014, 07:09 PM   #48368
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I would like to report that analog design is still alive and well, even though some of its most famous designers have passed away. The 'Analog Aficionados' event was brim full of both younger and older analog designers, some even older than me! And the conversation was brisk with notepads open and people sharing circuits there.
From the DIY people sometimes here, both Ron Quan and Kirkwood Rough were there big time, sharing their thoughts and opinions along with everyone else.
Kirkwood showed me a very interesting circuit that he had some problems with. I told him that he was 'nuts' to even attempt that design. '-) Ron reminded me that there really was a difference between PIM and FM distortion measurement, although I suspect that they both come from the same distortion mechanism.
There were lots of interesting people there, some really, really sharp.
The event was sponsored by Linear Systems, the fet source for DIY. Their work is progressing and their yields are increasing, leaving the future of complementary differential jfet input stages both possible and even 'improvable' with newer devices in future. Personally, I would rather go to this event than any other in the Bay Area. Of course, that's me, not most audio amateurs.
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Old 13th February 2014, 07:42 PM   #48369
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No one would bother with less than 64 bit floats about -300dB rounding floor.
When I play with MathCad the numerical noise is about -320dB.

Jan
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Old 13th February 2014, 11:10 PM   #48370
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Originally Posted by jan.didden View Post
When I play with MathCad the numerical noise is about -320dB.

Jan
Numerical resolution can be turned into an academic curiosity but it does not figure into day to day SPICE results. Folks used to make a big deal about the Motorola 80 bit floats vs. Intel 64 bit floats by inverting nearly singular matrixes with one vs. the other, mostly nerd games.
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