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From: helmut@cosy.sbg.ac.at (Helmut Mayer)
Subject: Re: Random Number Generator Effects
Message-ID: <D903yt.Kq8@wst.edvz.sbg.ac.at>
Sender: news@wst.edvz.sbg.ac.at (USENET News System)
Reply-To: helmut@cosy.sbg.ac.at
Organization: University of Salzburg / Austria
References: <3pqp8r$ekq@ixnews4.ix.netcom.com>
Date: Mon, 22 May 1995 22:32:53 GMT
Lines: 37

Jonah Thomas writes
# In <D8u79x.1Iw@hasler.uucp> root@hasler.uucp writes: 

# >The noise performance of op amps is repeatable and testable: how is this
# >different?
# 
# I'm not an expert in such things, I listen to experts and try to tell whether
# they're right.  I think you're right about the temperature and design issues.

Don't call me an expert, but having a master's degree in communications  
engineering I should know something about noise..;-)

Every simple resistor produces noise due to temperature. The frequency  
components of this thermal noise have (a very flat) gaussian distribution, so  
the model can even be made simpler and results in the concept of "white noise"  
where the spectral power distribution is uniform. White noise is uncorrelated  
and therefore statistically independent.
So I always wonder why people speak of hardware RNG, when the only thing they  
need is a resistor. Admittedly, the noise amplitude might be a bit low, but one  
could also use a noise generator used for testing of electronical circuits. The  
random output of these devices is definitely not repeatable, but I also don't  
understand why this should be of importance. Using just common sense it seems  
that an unpredictable RNG is better than a predictable one!?
Finally, a guess. In nature temperature also plays an important role in random  
(chaotic) processes at the macro level (weather) or the micro level  
(biochemical reactions) without caring for repeatability...

Best regards,

Helmut
--
Helmut A. Mayer, University of Salzburg, Department of Computer Science
*** Member of siGis ***
Jakob-Haringer-Strasse 2, A-5020 Salzburg, AUSTRIA
Tel.: +43-662-8044-6315  Fax: +43-662-8044-611
"...All I want is PEACE and LOVE on this planet, aint how that GOD planned  
it?..." - Chuck D.
