1st and 2nd order pink noise filters

Type : Pink noise
References : Posted by umminger[AT]umminger[DOT]com
Notes :
Here are some new lower-order pink noise filter coefficients.

These have approximately equiripple error in decibels from 20hz to 20khz at a 44.1khz sampling rate.

1st order, ~ +/- 3 dB error (not recommended!)
num = [0.05338071119116 -0.03752455712906]
den = [1.00000000000000 -0.97712493947102]

2nd order, ~ +/- 0.9 dB error
num = [ 0.04957526213389 -0.06305581334498 0.01483220320740 ]
den = [ 1.00000000000000 -1.80116083982126 0.80257737639225 ]