[sdiy] Uniformly distributed noise generator?

Scott Gravenhorst music.maker at gte.net
Mon Jun 10 16:50:44 CEST 2013


>cheater00 .  wrote:
>> It's not inconceivable that the specific random sequence which happens
>> right after power-on will in some way change the result of the test.
>
>Store the state when you shutdown. Or store the last n bits generated.
>Use those to initialize at power on.
>
>-- Daniel

This is a good idea and would prevent the repeat of the "sequence"
especially when sufficient bit width is used (I have a chart that shows
maximal sequences up to 168 bits if you need it - and that is an old chart
so by now there are probably charts that show even more bits).

Unless you start working with terahertz clocks, I don't see how one can get
"repeated lies".  I mean, if you pick out a 64 bit word from a 128 bit
LFSR, you will see the same numbers come up again and again, but in
different sequences, not repeats.

So Damian, I suppose that for you the question is then: where can I find a
truly perfect analog noise source that I can use in my application? 

My understanding and I will take correction here if I am wrong - there is
no such thing.  You are looking for a mathematical construct (I.e.,
computation, as in digital).  And IMO, the LFSR (long) fits the bill if you
envelope the parameters to allow for your time span of sampling and apply
what Daniel said above.

-- ScottG
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-- Scott Gravenhorst
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