[sdiy] cheap sine wave osc

[harrybissell at wowway.com]

Do you need equally-tempered tones ???

If so I'd use a top-octave generator chip (rare but not totally unobtanium)
and bandpass (resonant) filters. Essentially the filters would be near
self-oscillation and the top-octave would trigger (sync) them.

This would give arbitrary precision and no retuning in the field...

H^) harry



On Tue, 14 Aug 2007 16:14:01 +0200, Derek Holzer wrote
> Hi Magnus,
> 
> a filter with feedback was definitely on the list of options, and I 
> have some TL074s laying around to check it with. I'll hit the 
> datasheet and have a look. Thanks for the suggestion!
> 
> d.
> 
> Magnus Danielson wrote:
> > Hi Derek,
> > 
> > I would consider the classical state-variable filter sine/cosine oscillator.
> > You would need some form of amplitude limitation mechanism to balance the
gain,
> > but it is essentially a three-op-amp job with two integrators and a summer
> > setup with feedback. A TL074 can do it all. Maybe not dirt-dirt cheap, but
> > fairly cheap and still highly available components will work well.
> > 
> > Cheers,
> > Magnus
> >
> 
> -- 
> derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
> ---Oblique Strategy # 169:
> "Use filters"
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


Harry Bissell & Nora Abdullah 4eva