I am trying to get band limited saw-tooth wave. I have found this paper: Alias-Free Digital Synthesis of Classic Analog Waveforms.

I am prototyping this code in common LISP, here is snippet of what I wrote: https://pastebin.com/Ny4L0EH5

I managed to get something that in time domain looks like sawtooth but it has rising DC offset that causes output to approach infinity (this is generated by blit function).

I read that I should fix this with one pole high-pass filter. I have put simple IIR but without any good results. It makes sense for me to remove this DC bias this way since it is digital equivalent of RC differentiating circuit that block DC bias.

I have tried a few different sets of coefficients but without any good results.

I have looked hard with both duckduckgo and google for any information about DC offset correction in this method but i did not managed to find anything.

I have also tried to subtract from output sample average value of one period but again no luck.

I have saved to file band limited version of Dirac comb and tried to filter it with low pass filter in octave but it does not change time domain shape of data in any way, only amplitude decreases. I tried this because I read about this way of performing summation.


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