I am currently playing around with the concept of phase distortion. My Python prototype distorts the phase of a simple sine wave. When I set the distortion to high values to achieve something like a saw wave it will result in aliasing. I know why it occurs and now would like to do something to get rid of it (or most of it). So I'd like to do the following:
- Oversample the phase distortion oscillator, e.g. by four times.
- Apply an antialiasing filter around 20 kHz.
- Downsample by only using every fourth sample of the result.
So here are my questions:
- What kind of filters are "usually" used as antialising filters (in interactive cases)? IIR filters? FIR filters?
- Can someone provide me with an example implementation of an antialiasing filter or some good filter coefficients?