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PICList
Thread
'"Real" Random sequence sought'
1999\10\15@124828
by
Wilhelm Erouve
Looking for examples of a real random sequence for use with the 16f84. Have
generated a succesful psuedorandom routine and would like to work with the
real.
Thank you.
1999\10\15@132704
by
Dave Minkler
I can provide you with a real random stream 64k long in Intel hex
format. File runs 181k so is inappropriate for posting. Will email if
requested. Data stream was generated using a radiation based random
number generator (two PICs in that project) so is truly random.
Dave
1999\10\15@153858
by
Michael Lee
 Original Message 
From: Wilhelm Erouve <spam_OUTJRouvelleTakeThisOuTAOL.COM>
To: <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU>
Sent: Friday, October 15, 1999 5:47 PM
Subject: "Real" Random sequence sought
> Looking for examples of a real random sequence for use with the 16f84.
Have
> generated a succesful psuedorandom routine and would like to work with
the
> real.
This can easily be acheived by amplifying the shot noise across a PN
junction. Zener diodes are a particularly good source of noise. This is
random to the same degree as the radioactive decay method already suggested,
but obviously much more practical.
Once recorded, does a random sequence cease to be random as can now be
repeated at will, and is surely now  by definition  deterministic? Can
randomness be quantified? Any mathematicians out there care to enlighten
me?
Regards
Mick
1999\10\15@173824
by
Walter Banks
> Can randomness be quantified?
You can measure some things that will help qualify it.
The statistical distribution of the generated numbers of a
long sequence and the distribution of the numbers in pairs
and triplets of even longer sequences.
There is an incredibly good reference titled
"Statistical Distributions" by NAJ Hastings and J.B.Peacock
John Wiley 1974
ISBN 0470358890 or ISBN 0470264462
The LC number is QA273.6.H37
This rare book is essential for anyone doing MonteCarlo
simulations or using Random Number sequences. It
is a collection of simple algorithms for generating
random numbers with specific distributions given a simple
random number generator with good first and second
order distribution .
Walter Banks
1999\10\15@182105
by
William Chops Westfield
> Can randomness be quantified?
You can measure some things that will help qualify it.
The statistical distribution of the generated numbers of a
long sequence and the distribution of the numbers in pairs
and triplets of even longer sequences.
People should not that there are at least two kinds of random numbers.
"statistically random numbers" have predictable distribution patterns and
such, and are useful for monte carlo simulations and such. With
"cryptographically random numbers", the key attribute is nonpredictability,
with statistical properties coming in a distant second. You can have a
wonderful statistically correct pseudorandom number generator that is
useless for cryptography purposes.
BillW
1999\10\15@194924
by
Robert A. LaBudde

At 08:24 PM 10/15/99 +0100, Mick wrote:
>This can easily be acheived by amplifying the shot noise across a PN
>junction. Zener diodes are a particularly good source of noise. This is
>random to the same degree as the radioactive decay method already suggested,
>but obviously much more practical.
>
>Once recorded, does a random sequence cease to be random as can now be
>repeated at will, and is surely now  by definition  deterministic? Can
>randomness be quantified? Any mathematicians out there care to enlighten
>me?
There are a number of tests for 'randomness'. One of the key
characteristics for 'randomness' is that there be no time (or serial)
correlation present. Since the autocorrelation function is the Fourier
transform of the power spectrum, this translates into a requirement for a
constant power spectrum of infinite bandwidth.
One of the best and most accepted tests of 'randomness' is to compute a FFT
and examine the degree of nonconstancy of the power spectrum.
================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS email: ralKILLspamlcfltd.com
Least Cost Formulations, Ltd. URL: http://lcfltd.com/
824 Timberlake Drive Tel: 7574670954
Virginia Beach, VA 234643239 Fax: 7574672947
"Vere scire est per causae scire"
================================================================
1999\10\15@195337
by
Sean H. Breheny
At 07:48 PM 10/15/99 0400, you wrote:
>
>There are a number of tests for 'randomness'. One of the key
>characteristics for 'randomness' is that there be no time (or serial)
>correlation present. Since the autocorrelation function is the Fourier
>transform of the power spectrum, this translates into a requirement for a
>constant power spectrum of infinite bandwidth.
>
>One of the best and most accepted tests of 'randomness' is to compute a FFT
>and examine the degree of nonconstancy of the power spectrum.
Ok, but can't you easily construct a signal that is not random, yet has
such a spectrum (up to some limiting BW, which would also be true for a
truly random signal when fed into a real amplifier)?
Sean
{Quote hidden}>
>================================================================
>Robert A. LaBudde, PhD, PAS, Dpl. ACAFS email:
.....ralKILLspam.....lcfltd.com
>Least Cost Formulations, Ltd. URL:
http://lcfltd.com/
>824 Timberlake Drive Tel: 7574670954
>Virginia Beach, VA 234643239 Fax: 7574672947
>
>"Vere scire est per causae scire"
>================================================================
>

 Sean Breheny
 Amateur Radio Callsign: KA3YXM
 Electrical Engineering Student
\=
Save lives, please look at http://www.all.org
Personal page: http://www.people.cornell.edu/pages/shb7
EraseMEshb7spam_OUTTakeThisOuTcornell.edu ICQ #: 3329174
1999\10\16@055836
by
Dr. Imre Bartfai
1999\10\16@071815
by
Russell McMahon
>I have posted a true hardwarebased random generator for the PIC. It uses
>a baseemitter junction of a GePNP transistor as a noise source and a
>twostage op. amp amplifies it to the TTL level. I attach it for your
>convenience (1,5 k only).
Useful circuit.
Note that the transistor used is somewhat critical if 5 volts is to be
used  the junction on some (many?) silicon transistors will not exhibit the
required zener action until about 9 volts is applied  which is no doubt why
a germanium device was specd. Experimentation may reveal some silicon
transistors which will work OK here.
Note that an NPN can also be used if the transistor base is taken to ground
and the 4K7 taken to Vcc.
Russell McMahon
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