PWM on triangle wave affects shape?

[Modeler]

I was playing with the demo of CS-80V and discovered that its oscillators do something weird. The triangle wave is modulated by the pulse width controls and "morph" between a triangle, saw and ramp wave. I have never seen this before and can't find another plug-in that does it. This raises a few questions:

A. I thought pulse width modulation only works on pulse waves, so what should it be called in this case?
B. Does the original CS-80 do this? I'm assuming it does without expressing Arturia fanboyism.
C. What other synths / plug-ins do this?

Calling all synth purists and sound design gurus!

[Modeler]

I've been doing some research and I think this is called slope modulation. PolyIblit is capable of this.

I'm not about to write a book on this any time soon, so please chime in if you know what this is all about. Could someone perhaps start a wiki page for this?

[jupiter8]

A. This is a semantics issue. If you do pwm on anything but a pulse wave it isn't pwm per definition. However pwm is what most people would call it intuitively and makes most sense. And "inventing" new buzzwords is a bit silly if you ask me. So just call it pwm even though technically it isn't. It is phase modulation.
B. I don't think so. If you look at the front panel of a CS 80 there is an arrow from the pwm section to the pulse wave but not to the triangle.

If you have your waves as single cycle samples you can do pwm on any waveform. You just play the first and second half at different speeds. So i assume Arturia just added to make a more interesting synth. Why limit yourself to an exact replica ? (Tech note: I doubt Arturia does the oscillators with single cycle waveform samples but that is another story)
C. Probably plenty. The Roland Juno 1/2/mks 50 had an interesting pwm implementation on the saw wave.

[MaliceX]

You can do something like this and actually see the resultant waveform with Jeremy Evers Atlantis, and you can also modulate a lot of other things in the oscillators.

[Modeler]

If you look at the front panel of a CS 80 there is an arrow from the pwm section to the pulse wave but not to the triangle.

Thanks for your input jupiter8. That arrow is also absent from CS-80V, moreover the symbol that denotes the triangle wave (above the right-hand switch) appears to be absent from the real CS-80! Arturia's creation is a strange beast, a clean pulse wave looks like this:



Again I'm assuming this was modelled on the real CS-80's oscillators, hence the whole point of an emulation rather than simply using a couple of instances of Synth1

[AdmiralQuality]

Poly-Ana does that. PWM of any waveshape, not just pulse. And waveform morphing between the 4 primary waveshapes. All modulatable.