" f.bardet@voila.fr wrote:

Hi list, I need to analyse the low-frequency (1 to 5 Hz) content of a non-audio signal. So I'd like to proces Fourier Transform of my low-frequency, low sampled signal, within PD. As my incoming signal is low-sampled at 25Hz (coming from a camera), i think i can't use fft objects designed for audio processing. Do i have to rewrite an fft algorithm within pd, for low-frequency processing, or does this exist yet ? Has anyone built such a process in PD ?

hi there might be 2 ways of doing that:

1. signal-domain: you can downsample a signal with [block~] (see

3.audio.examples/J09.up.downsampling.pd) and use the [rfft~]-object 2) message-domain: i think (but have no idea whether this has already been done by thomas; and i don't know whether he has released it yet) that the iemtab-library allows the fft of a table to be calculated. probably there are some other externals that allow fft's on tables (e.g. message data)

mfg.a.dr IOhannes