[sharing] Vector Phaseshaping Synthesis

I found myself implemented this synthesis technique after reading this paper :

http://recherche.ircam.fr/pub/dafx11/Papers/55_e.pdf

It's a great development of phase distortion synthesis and quite an original way of generating formants. However, as all non linear synthesis technique, it does generate quite a bit of harmonics. By linearly interpolating between 2 adjacent formant integer ratios and oversampling, the aliasing can be reduced quite a lot. But it is quite costly in terms of CPU.

What I found really interesting is that the paper includes a novel single oscillator anti aliasing technique. But I haven't been able to reproduce it yet in gen~. The algorithms doesn't seem too complicated in the paper but every time I tried to adapt it, the result was just the opposite of what it was meant to be . I found a python implementation by one of the author but I can't seem to adapt it either to gen~ codebox.

Anyway I'm including the implementation using the linear formant interpolation technique. I also included the python code in a gen~ codebox elsewhere in the patch in case someone more gifted than me is willing to have a go at it ! ;) I will still keep on trying though.

Enjoy!