antialiasing filter?

May 14, 2006 at 2:53pm

antialiasing filter?


Just wondering if there is a way to do antialias filtering? Perhaps an object that I could use to filter the output of the phasor~ object for example.

Thanks for your help.

May 14, 2006 at 4:30pm

You need to filter aliasing before it occurs in the signal, because you
can’t filter the aliased frequencies out of an already aliased signal. Put
your phasor in an up-sampled poly~, followed by a lowpass/brickwall filter.
There are different filters you could use like butterworth or FIR. I’m not
sure what’s best.
If you just want anti-aliased oscilators use saw~/tri~/rect~

hth, -thijs

May 14, 2006 at 8:04pm

Anything in the lowpass familiy should work
Biquad~ (with low pass coeffs)


May 15, 2006 at 5:32am

I have made a butterworth low-pass filter, tl.butterlp~. Butterworth
filters have a flat frequency response in the passband. I also have a
more expensive filter CPU-wise: tl.crossover4~. That is a fourth order
Linkiwitz-Riley filter.



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