[sdiy] Reverse Sawtooth

[Olivier Gillet]

> To keep things as compact as possible for the small device in question, I'm
> lumping them all into a single wavetable. When I start generating a
> waveform, the array pointer is initialised to 128 * w, where w is the value
> in the table above.
>
> If there's no significant difference in sound between a saw and a reverse
> saw, there are obvious savings to be made.

They sound the same as audio rates, it's only phase shifts. If they
didn't, you would have to throw away all the audio circuits which
invert their inputs because they have an odd number of inverting
buffers/stages in the chain!

I see only two use cases for the reverse sawtooth:
- at low-frequency, as a control signal, it's an entirely different story!
- sawtooth + dephased inverse sawtooth = cheap square PWM from wavetables.

Olivier