It is, in fact, an aliasing problem.
I changed the code to use a sine table wich works fine.
Then I implemented a phase distortion saw oscillator similar to the
casio CZ series.
when i increase the harmonic content (morph more and more to saw) I get
the clicks again.
But this is a special case and comes from a coincidence between the odd
sample rate the codec is running at.
The codec is running at approximately 44002 kHz and the oscillator is
running at 440 Hz.
Somehow the beating of the harmonics and the mirrored frequencies
generates a clicking beating of the harmonics.
I can post an audio example later on since i don't have the board at
hand at the moment.
julian
Am 10.04.2012 17:54, schrieb Nigel Redmon:
Not alone, Emanuel.
"Clicks", especially 2-3 seconds apart doesn't describe aliasing—and looking at
the spectral distortion seems to be a separate issue. Julian, does that still describe
the problem you're hearing, after your recent code changes?
On Apr 10, 2012, at 6:40 AM, Emanuel Landeholm wrote:
Hi,
Hm, am I alone in thinking that truncate interpolation shouldn't give
clicks every 2-3 seconds..? How big is your table? There must be a bug
in your table offset code, but I can't find it in the code you posted.
If you really have clicks that seldom, linear or higher interpolation
will not help you.
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