[music-dsp] Resampling, Interpolation
akbutler at tiscali.co.uk
Sun Oct 7 07:36:52 EDT 2007
Here's a little demo I made.
Started with a 1kHz sine tone (made in audition)
of 2s duration (repeated 2x)
...at 44100Hz sample rate
Resampled the first repeat using linear interpolation,
so that pitch drops linearly down to zero over the 2s
There's audible artifacts.
I'd call it aliasing, but not sure if it 100% matches the technical description.
If, as seems to be stated on this list, linear interpolation is good for
8x oversampled signals then the 1000Hz tone sampled at 44100Hz wouldn't
give aliasing when re-sampled.
Surely, this demonstrates something interesting.
Either that, or I misunderstood what was being said ;-)
To prove that the artefacts are the linear interpolation,
and not some quirk of my programming the second repeat
is shifted using identical software
apart from the interpolation (Mathons Chopitch).
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