[sdiy] Through-Zero FM

[Fahl, Romeo]

If you think of a normal (non-thru zero) VCO as a wheel that spins in
one direction, faster or slower depending on the frequency modulation -
a Thru-zero VCO actually changes direction with polarity changes in the
modulation.  Hard to describe how it sounds differently from a regular
VCO... but I'd say it's definitely thicker.  There's some good articles
in Electronotes on this.  Rene Schmitz has a Thru-Zero VCO design on his
site that doesn't rely on CEM3340's... you might want to check that out.

Romeo

 

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl 
> [mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Tim Parkhurst
> Sent: Thursday, December 16, 2004 3:31 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Through-Zero FM
> 
> So I'm looking at JH's site (looking for a picture where 
> someone had made a nifty little PCB for use with SMT 
> tempcos... I thought it was JH), and I see he has several 
> VCOs with "Thru-Zero" FM capability. I've seen this term 
> bandied about before (especially with respect to frequency 
> shifters), but I've got to admit I don't really understand 
> what it is or why it would be useful. Anyone care to enlighten me?  
> 
> 
> Tim (not afraid to ask the really stupid questions) Servo
> 
> "Epoxy always has the right 'thread' " - Toby Paddock
> 
> 
> 
> BTW - also got an email from Jay saying that he wanted to 
> make good on the tempco order. This is excellent news.
> 
> 
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