Any chance of a square wave osc with pwm?

Hi Brian,
Any chance of a square wave osc with pwm?
Thanks!

At least 99%. :smile_cat: Aliasing version first.

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I’m assuming we could add a filter directly after the oscillator and set it to the highest cut-off frequency value to act as an-antialiasing filter?

Unfortunately, no. Sampling a waveform containing frequencies above the half the sampling rate (Nyquist) will fold (i.e. alias) those high frequencies down into the lower frequencies so that a low pass filter is not effective. The low pass filter has to be applied before sampling.

There are many techniques for anti-aliased digital oscillators and its something that has been gone over many times by others. Here is an interesting recent one:

http://www.yofiel.com/software/cycling-74-patches/antialiased-oscillators

Once I have time to do a proper survey of the field and make some evaluations, I will be adding antialiased oscillators to the mix.

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Gotcha, as this isn’t an analog brick wall filter before hitting an ADC chip… so it has to be done at the code level.

No stress - the oscillators sound great so far! :slight_smile:

Finally got round to reading this - amazing - thanks for sharing!

Imagining anything better is way beyond my brain power - stoked to think we will be getting something like this in the ER-301 :smiley: