MOTM

Use PIC with ADC, measure Zener Diode noise (amplified).

Paul S.

----- Original Message -----
From: The Old Crow <oldcrow@...>
To: <motm@egroups.com>
Sent: Wednesday, May 24, 2000 4:13 PM
Subject: Re: [motm] LFO Tap and Division


>
> On Tue, 23 May 2000 davevosh@... wrote:
>
> > crow,
> > i`d love to see a source of uncorrelated ( say 3 or 4 ) random triggers
> > derived from such a noise source. any chance ?
> > best,
> > dave v.
>
>   Uncorrelated?  That would require good old shot noise to be truly random
> between concurrent triggers.  In a PIC, I can rig several long feedback
> shift registers and thus create pseudo-random noise by instructing the
> regs to shift at a rate of 40KHz, but unless the seed number can be set by
> some sort of "real-world random" for each register, the triggers would
> actually be correlated by the finite (long, yes, but still finite) shift
> register bit patterns.
>
>   Hm, now this has me thinking.  I have methods I've used in the past to
> get fairly "true random" seeds that involve detecting the error in
> thermocouple cold-junction compensation servo loops, but that might not be
> the best solution here (as I'm not trying to build a process controller
> here). What might be of more use to us however is some way of setting
> specific random seeds by hand and then load/start the registers.
>
>   A "random" sequencer for triggers is what I'm arriving at here.  Some
> way to set a seed with a load jack/pushbutton, a clock rate switch to run
> it at 40KHz for audio uses or select a manual shift clock from a VCO or
> whatever.  I'll have to puzzle over it a bit to see if what I'm thinking
> actually works the way I want it to.
>
>   And here I just wanted to use my PIC part that I use to replace the
> flimsy digital noise chip Prophet-5s used.  Now look what it has become.
> ;)
>
> Crow
>
> /**/
>
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