[sdiy] Adding "sync" to a Through-Zero Sinewave Oscillator design

[David G Dixon]

It brings it to 0V, but I'm not sure that it starts off in a certain
direction or not. 

> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On 
> Behalf Of Tom Bugs
> Sent: Saturday, September 15, 2018 11:55 PM
> To: synth-diy at synth-diy.org
> Subject: Re: [sdiy] Adding "sync" to a Through-Zero Sinewave 
> Oscillator design
> 
> David - does your hard sync do as Don suggests "
> 
> the sync pulse should bring it to 0V, ascending.
> 
> "
> 
> I've always used this hard sync approach but the waveform can 
> rise or fall from this reset point.
> 
> (sorry, straying off topic)
> 
> 
> On 16/09/2018 07:45, David G Dixon wrote:
> > The Intellijel Rubicon 2 is a through-zero VCO which I 
> designed, and 
> > it has both kinds of sync.  We call them "Hard" and "Flip" on the 
> > panel, but I always think of them as "Reset" and "Reverse".  The 
> > Resetting sync is achieved in the normal way, with a JFET 
> across the integrator capacitor.
> > The Reversing sync is achieved by syncing to the threshold 
> input pin 
> > of the comparator in the tri-square core.
> >
> >
> >
> >> -----Original Message-----
> >> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] 
> On Behalf Of 
> >> Donald Tillman
> >> Sent: Saturday, September 15, 2018 10:31 PM
> >> To: ulfur hansson
> >> Cc: synth-diy mailing list
> >> Subject: Re: [sdiy] Adding "sync" to a Through-Zero Sinewave 
> >> Oscillator design
> >>
> >>
> >>> On Sep 15, 2018, at 3:26 PM, ulfur hansson 
> <ulfurh at gmail.com> wrote:
> >>>
> >>> I love the way traditional triangle core oscillator sync
> >> sounds, and much prefer it to the harsher sawcore type sync.
> >> with trianglecore sync (I hope I understand this correctly) the 
> >> waveform changes sign at trigger points rather than doing a hard 
> >> reset to 0v, right?
> >>
> >> There are several way to sync a triangle wave.
> >>
> >> The technically correct way would be to force the 
> oscillator to the 
> >> start of the waveform.  So if it's advertised as a sine wave, the 
> >> sync pulse should bring it to 0V, ascending.
> >>
> >> I'll claim that reversing the direction of the wave is not 
> actually a 
> >> sync.  The word "synchronize" means to bring an oscillator to the 
> >> same frequency, and same phase, as another.
> >>   I don't think that's remotely possible by flipping the 
> direction of 
> >> the triangle every cycle.
> >>
> >> I'd even call it "anti-sync".
> >>
> >> But if it's an expressive sound, it's probably worth 
> coming up with a 
> >> better name.
> >>
> >>    -- Don
> >> --
> >> Donald Tillman, Palo Alto, California http://www.till.com
> >>
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> >
> 
> -- 
> BugBrand LTD
> UK company No. 07199808
> VAT No. GB 988 2629 57
> 1 Ninetree Hill
> BRISTOL BS1 3SB
> United Kingdom
> www.bugbrand.co.uk
> 
> 
> ---
> This email has been checked for viruses by AVG.
> https://www.avg.com
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy