Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.COM (Dave Haynie)
Newsgroups: sci.physics
Subject: Re: Re: Minor nit on psi experiment.
Message-ID: <979@cbmvax.cbmvax.commodore.COM>
Date: Mon, 10-Nov-86 14:08:38 EST
Article-I.D.: cbmvax.979
Posted: Mon Nov 10 14:08:38 1986
Date-Received: Mon, 10-Nov-86 21:53:00 EST
References: <6287@decwrl.DEC.COM>
Organization: Commodore Technology, West Chester, PA
Lines: 47

> A third design for a REG is sometimes used for convenience but is
> considered much less rigorous.  A human operator hits a button which stops
> a clock. The accuracy needed to "control" this situation is measured in
> milli- or microseconds, which is thought to be much smaller than the
> capabilities of the human nervous system.  The random variability used here
> is that of the nervous system.  This is usually used in the form of hitting
> a keyboard key which causes the low order bit(s) of the system clock to be
> read on a computer.  This has the advantage of requiring no special
> equipment but raises a host of issues as to its reliability, theoretical
> correctness and interpretation. 

I used something related to this for a design project in an EE class long 
ago.  The objective of the project was to design a set of electronic dice
that would exhibit random behavior.  Something that could be made to
exhibit pseudo-random behavior (the same sequence could be easily recreated
by starting with the proper seed) was not acceptable.  I built the dice with
a pair of modulo 6 counters that were driven by a high speed clock (typical
speed of 500KHz).  The high speed clock's frequency was modulated by an
unrelated and very slow clock, with a period of several seconds.  A person 
could press the "roll" button and hold it indefinately, though upon being
released the "roll" would continue for about 1/2 a second.  This roll was
assumed to be a fixed length, though it wasn't required to be.  The end
result was a system that appeared very random.  This randomness was based
on the inability of a human to press the switch at exactly random intervals
though, a machine closing the switch in a very exacting way would produce
a pseudorandom string of rolls based on the product of the machine's rate
and the two other unrelated rates in the dice circuit.

> 		Topher Cooper
> 
> USENET: ...{allegra,decvax,ihnp4,ucbvax}!decwrl!pbsvax.dec.com!cooper
> INTERNET: cooper%pbsvax.DEC@decwrl.dec.com
> 
> Disclaimer:  This contains my own opinions, and I am solely responsible for
> them.
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dave Haynie	{caip,ihnp4,allegra,seismo}!cbmvax!daveh

	"Laws to supress tend to strengthen what they would prohibit.
	 This is the fine point on which all the legal professions of
	 history have based their job security."
						-Bene Gesserit Coda

These opinions are my own, though for a small fee they may be yours too.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~