[sdiy] saw to tri/sine options

[David G. Dixon]

Kyle,

That's a very interesting question!

After reading your post, I opened up my VCO simulation program in Multisim
and changed the triangle input to the virtual sine shaper to some other
waveforms.  Here is what I got:

For saw input, the result is a saw with a sigmoidal (i.e., S-shaped)
downslope rather than a straight one.  It's basically the downward sloping
half of a sine wave, which stands to reason.  I would bet that this waveform
sounds rather pleasant.  I'll have to give it a try.

For pulse input, the result is a pulse output with no shaping at all. (!)
Who knew?

Cheers,
Dave

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Kyle Stephens
> Sent: Monday, June 01, 2009 8:25 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] saw to tri/sine options
> 
> 
> A little out of idle curiosity (and to better under stand how the concept
> works), what happens when you put a non-triangle wave through a tri to
> sine waveshaper?
> 
> Say you use a saw, does that get you a halfway-there sine? By my same
> possibly misplaced logic, would a square wave not be affected much, if at
> all?
> 
> I at least haven't seen something like that before, so guess the results
> aren't all that interesting?
> 
> 
> _Kyle
> 
> --- On Mon, 6/1/09, mark verbos <mverbos at earthlink.net> wrote:
> 
> > From: mark verbos <mverbos at earthlink.net>
> > Subject: Re: [sdiy] saw to tri/sine options
> > To: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
> > Date: Monday, June 1, 2009, 5:17 PM
> > These are essentially time
> > independent. They are just a transfer
> > function of voltage in to voltage out. So, perfectly. I
> > would think.
> >
> > Mark
> >
> >
> >
> >
> > On Jun 1, 2009, at 6:07 PM, Jerry Gray-Eskue wrote:
> >
> > >
> > > I am curious, How well do these hold the waveform peak
> > to peak
> > > voltage and
> > > sine wave shape from low to high end frequencies?
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: synth-diy-bounces at dropmix.xs4all.nl
> > > [mailto:synth-diy-bounces at dropmix.xs4all.nl]On
> > Behalf Of mark verbos
> > > Sent: Monday, June 01, 2009 4:14 PM
> > > To: Scott
> > > Cc: Synth DIY
> > > Subject: Re: [sdiy] saw to tri/sine options
> > >
> > >
> > >
> > > On Jun 1, 2009, at 4:37 PM, Scott wrote:
> > >
> > >> I'm trying to pick out a saw to tri/sine converter
> > for a VCO I'm
> > >> building (j.h.living).  Is there much
> > difference between the various
> > >> types?  Looking through my bookmarks I see a
> > few..
> > >>
> > >> Bergfotron uses transistors
> > >> http://hem.bredband.net/bersyn/VCO/Saw%20to%20tri-sin%20W.gif
> > >
> > > This was pulled from the Moog Modular I believe.
> > Jörgen seems to like
> > > it a lot.
> > >>
> > >>
> > >> ASM uses diodes
> > >> http://www.elby-designs.com/asm-2/vco/vco1-shaper-asm2-cct.pdf
> > >
> > > This one is also used by Doepfer. It's light on parts,
> > but high on
> > > harmonic distortion.
> > >
> > >
> > >>
> > >>
> > >> rwilson uses a 13700 (nothing direct, but it's on
> > the VCO schematic)
> > >>
> > >
> http://www.musicfromouterspace.com/analogsynth/VCO200604REV01/vcoschematic
> pa
> > > ge2.gif
> > >>
> > >> Thanks!
> > >>
> > >>
> > >>
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> 
> 
> 
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