Casio CZ/ VZ/ FZ - Pro Series

>Having investigated a bit more, I came to the conclusion that it might
>not be PD synth, but what I call additive square wave synth.

I wouldn't really think that it's an "additive square wave" synth.  The Poly 
800 was a bit of a special case.  I'm pretty sure it used a sound chip 
intended for arcade games.  I think the Siel DK 70 and DK 80 used the same 
chip.  Anyway the trick with the 800 is that if you had the waveform on 
square, all the different wave footages that were turned on would have the 
same amplitude, and if the saw wave was selected, the different footages 
would have different amplitudes so it would approximate a saw wave, much 
like the sample you've got on the page.  You probably knew that already.  
Anyway what I'm getting at is while that arrangement could make the saw 
wave, it couldn't make most other waves without being able to adjust the 
phase and pulsewidth of each square wave independently.  Think about how you 
would go about making a triangle wave out of just squares- one square wave 
to get the basic shape of it, then add 2 different pulse waves, one 25% duty 
with a 90 degree phase shift, and one 75% duty with a 270 degree phase shift 
(I think..) then more to refine it further.  I worked it out on paper but 
I'm not really sure if I got that right or not.  At any rate what I'm 
getting at is that it would be very difficult to get most waves this way.

Seeing as how it has 16 steps, the saw wave looks more like it comes out of 
a 4-bit DAC.  To me this would seem pretty likely.  It still doesn't explain 
how the waveforms are made, and particularly why they're affected by the 
amplitude envelope, but it makes some sense...

I could look at the waves on my computer and try to get a better idea of 
what's going on...

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