In the books it's supposed to be like the natural sounds of the desert, sand shifting and such so the worms don't take take notice. Even as good as Paul was when he first met the Fremen he was admonished for how loud he was and the trail he left (well just by Chaini really), in the books anyways, I still have to watch pt 2.

White noise static is random but also follows a pattern so that any chunk of white noise will look pretty much identical to any other chunk of white noise. If they are replicating a wind noise it would be pretty much the same as white noise, totally random but following a strick pattern.

See also how any normally distributed random event will create a bell curve of probability. The pattern is so strick it is a corner stone of statistics, however it's cause it's pure randomness.