Yamaha Synths, Phase Modulation

[KA4HJH]

>I proposed that the VCA operation could be performed by adding two
>different sine lookup phases and you wouldn't need an actual
>multiplier for your VCA.  Well, that's not *exactly* how they did
>it...  The sine lookup table supplies the log of the sine, the VCA
>control "voltage" is added to that, and then it goes to an exponential
>lookup ROM to complete the multiply.
>
>Still, no real-time multiplies.

And they said the slide rule was dead. You can always subtract sines, 
but then you get a phase shift...

Terry Bowman, KA4HJH
"The Mac Doctor"

ICQ: 45652354