Random Number Generators

[John A. Thomas]

You might find this article instructive:  Herschell F. Murry, "A General 
Approach for Generating Natural Random Numbers," IEEE Transactions on 
Computers, December 1970, p. 1210.

A fairly recent patent uses your approach of two oscillators:  No. 
4,855,690 by Dias, assigned to Dallas Semiconductor Corp., "Integrated 
Circuit Random Number Generator using sampled output of variable 
frequency oscillator."

I'd suggest using Johnson noise; reverse-biased diodes generate noise 
which is pink.  Ive built devices using amplified Johnson noise, squared 
up with a comparator, then averaged by a D flip-flop.  The preliminary 
results look pretty good.  

Please post your results here -- and good luck. 

John A. Thomas
jathomas at netcom.com