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From: daveh@cbmvax.cbm.UUCP (Dave Haynie)
Newsgroups: sci.physics
Subject: Re: Re: Re: Minor nit on psi experiment.
Message-ID: <984@cbmvax.cbmvax.cbm.UUCP>
Date: Wed, 12-Nov-86 13:30:28 EST
Article-I.D.: cbmvax.984
Posted: Wed Nov 12 13:30:28 1986
Date-Received: Wed, 12-Nov-86 21:54:43 EST
References: <3807@columbia.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 40

> 
> In article <979@cbmvax.cbmvax.commodore.COM> daveh@cbmvax.commodore.COM (Dave Haynie) writes:
>>
>>I used something related to this for a design project in an EE class...
>>						....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....
>>						....This randomness was based
>>on the inability of a human to press the switch at exactly random intervals...
> 
> Just a quick question. Was the slow clock modulation result of some
> analysis or just a means to make the "random" numbers more random?
> 
> zdenek

The slow clock itself was the best way I could find to introduce randomness.
The components allowed in the circuit were very limited, and the main point
of the exercise was to come up with some reasonable way to do the roll
randomly.  The time periods were chosen with some thought.  The fast clock
was picked so that even small changes in the frequency would cause a large
change in the number of counts through the two die counters.  The fixed
"roll" time was set at around a 1/2 second mainly because that time looked
good, it appeared to most people to be a "good roll"; a shorter time would
have been OK, but not as ergonomic.  The slow clock time was chosen to be
quite around 10 time the length of the fixed roll, but no direct multiple
of this roll.  This scheme turned out to work very well, though I never
did any formal analysis of its "randomness.
-- 
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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.

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