Gaussian dithering

Type : Dithering
References : Posted by Aleksey Vaneev (picoder[AT]mail[DOT]ru)
Notes :
It is a more sophisticated dithering than simple RND. It gives the most low noise floor for the whole spectrum even without noise-shaping. You can use as big N as you can afford (it will not hurt), but 4 or 5 is generally enough.
Code :
Basically, next value is calculated this way (for RND going from -0.5 to 0.5):

dither = (RND+RND+...+RND) / N.
           \           /
              N times

If your RND goes from 0 to 1, then this code is applicable:

dither = (RND+RND+...+RND - 0.5*N) / N.