This circuit produces several noise channels which are shaped with indidual euqalizers in order to achieve the desired spectrum. The specific profile of the harmonics according to fourrier analysis is taken into account here. The FIR is designed to limit frequencies to the 5th harmonic while the amount if overlapping of the channels make sure that the harmonics add to a flat profile.

In modifiying the scale factors for the channels, it is possible to aproach the profile to white noise, brown's noise and pink noise.

Screenshot of a logic analyser with white noise setting

Screenshot of a logic analyser with pink noise setting

See the code here: noiseshapping.c

Conclusion and Summary

 PLDs can be used to generate versatile noise signals for audio applications.