is there an object or a patch that does akima interpolation?

I need it to upsample a data-file with 256Hz sampling rate to the audio-domain (22.05kHz or 44.1kHz).

how to do that in pd ?

Thanks!
plu

If you wish to preserve the data integrity then you want to avoid interpolation. Just read it in via [textfile] to a table and use [tabread~] to access it in the audio signal domain.

If the data is sound (presumably infrasound/siesmic data) and you want to "hear" it then using [tabread4~] and a lowpass at the original Nyquist (128Hz * upsample factor) will give you some okay results. You will still get upsampling artifacts.

It's hard to answer this question as such a low sample rate is unusual and it isn't clear what this data represents. It rather depends on how you want to use it. If you are looking to avoid any upsampling errors then for such a huge jump you certainly need much better than linear interpolation (weighted sinc functions etc)

You will find informative links on the subject here:
http://wiki.hydrogenaudio.org/index.php?title=Resampling