[sdiy] LFSR digital noise source

rsdio at audiobanshee.com rsdio at audiobanshee.com
Mon Nov 11 01:27:38 CET 2019


I’d say there are two important qualities of noise: distribution of values, and spectrum.

I can’t hear the difference between distributions, at least not for an audio waveform. When used as a CV source, the distribution could be very important. Digital noise should have a Uniform Distribution. Most analog noise sources probably have a Gaussian Distribution. If you add two independent Uniform Distribution sources, you get a Triangular Probability Distribution, with the distribution approaching Gaussian as more are added. When using noise for dither, the distribution is very important. I doubt that’s the application, here, though.

As for spectrum, I assume that digital noise will be purely white. Analog noise might have various “coloured" spectra. With a precise filter, the digital white noise can be shaped to other spectra such as pink or red, etc.

Brian


On Nov 10, 2019, at 4:09 PM, ColinMuirDorward <colindorward at gmail.com> wrote:
> Hope this isn't too off topic, but I've often wondered when/why you'd choose a digital noise source over an analog one. It is simply for the acoustic flavour?
> 




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