[sdiy] Popcorn Noise Generator?

[Ian Fritz]

At 03:36 PM 7/10/05, Magnus Danielson wrote:

>First create a long PRBS generator, operating at a multiple of the final
>sampling rate. It is a simple matter of shift-register and XORing with the
>polynom if the top bit is 1. This generates white noise.
>
>Then, integrating the scaled output of the PRBS. This is done by adding or
>subtracting the scale amplitude due to a 1 or 0 output of the PRBS 
>respectively
>to the previous integrator output sample.
>
>Now we have our popcorn noise, but in a too high sampling frequency, so we
>perform a down-sampling by FIR filtering and using every other sample in a few
>rounds.

So from what I have been reading, popcorn noise has a 1/f^2 power spectrum 
above a cutoff fc.  So a first order lowpass operating on white noise might 
be a good way to go.

popcorn power ~ 1/(1 + (f/fc)^2)

<http://home.zcu.cz/fel/kae/aes2/sumy/noise_sim_tp.pdf#search='popcorn%20noise%20spectrum'>