Re: Want a random entropy source?

[John Bradford <john@grabjohn.com>]

> I was astonished to see that the resulting signal is a white-noise
> pattern with a slight emphasis at the high end (when sampled at 44
> kilosamples per second). In short, it looks like diode noise with a
> 4 kilohertz square wave thrown in.

> "That suggests to me that this would make a fair source of random samples, 
> especially after you slot out the interfering signal.

How can you guarantee that you are sampling noise, though, what if a
sound card was picking up 50 Hz mains hum, for example,  that would
de-randomise the data quite a bit.

> "How many computers don't have cheap sound cards and CD-ROM drives?"

I have never understood how a 16-bit DAC or ADC can have noise above
96 dB.  Surely _by definition_ a 16-bit DAC or ADC is one that does
not have noise above that level.

John.