Doepfer

Hi Florian,

Maybe I don't understand the issue, but seems to me this should FM correctly. The sine 
converter *always* maintains an exact phase lock with the tri core. So however the core is 
modulated the correct sine phase is produced. Do you have a specific example where this 
wouldn't work for FM?

Looking at a the Synclavier FM oscillator design, looks like they too used a triangle-to-
sine converter but in the digital domain. The phase index is a ramp generator (triangle) 
that feeds a triangle-to-sine wave lookup table to generate the final sine shape. They 
called it "phase modulation" so Yamaha won't sue them, but sounds like pretty good FM to 
me.



--- In Doepfer_a100@yahoogroups.com, Florian Anwander <fanwander@...> wrote:
>
> Hi Laryn
> 
> 
> > Actually the high-quality sine circuit is *quite* common. According to my schematic 
> > library, most vintage oscillators used this standard design. For example, my Aries 
VCOs 
> > produce a pretty good purity sine using this:
> > 
> > http://www.leinermedia.net/aries/AriesSchematics/AR-317s.gif
> Sorry, these are converters, but no sine oscillators. it is a sine-like 
> waveform, but not a sine. Every frequency modulation affects the core 
> oscillator, not the sine. So the result will be what the waveform 
> converter makes out of the fm'ed core waveform, but will not be a fm'ed 
> sine.
> 
> Florian
>