[PD] framp~ -- a phase vocoder ?

Miller Puckette mpuckett at man104-1.ucsd.edu
Wed Jun 6 19:51:16 CEST 2001

Guenter's right... I completely forgot I ever wrote that (I ended up finding
a cleaner way to do phase vocoder proper but framp~ might still be
very useful for something else...)

The input should be an UNWINDOWED fft; the outputs give the frequencies
(in Hz.) and the linear amplitudes measured for each channel of the FFT.

To resynthesize, I think you multiply the frequency by the hop size in seconds
to get phase change; then update teh phase of the output by rotating by
the phase change (complex-multiply by exp(i * phasechange))...  but I don't
think I ever tested this idea out...


On Wed, Jun 06, 2001 at 06:50:41PM +0200, guenter geiger wrote:
> Hi there !
> The only information about the framp~ object I found was in the
> help screen saying 
> framp~ -    output a ramp for each block
> Now I got curious for what this might be needed (I am thinking about how
> to implement zero padding)
> .. after looking at the code this seems to rather be
>  FRequencyAMPlitude .. which means a phase vocoder analysis ... right ?
> Which in turn throws up the question how to do the vocoder synthesis
> e.g framp -> fft converter.
> Would be nice for high quality fft filters.
> Guenter

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