SV: Re: [sdiy] VCO autotune for poly analog modular

[karl dalen]

Use linear VCO no tuning!

KD


--- Magnus Danielson <cfmd at bredband.net> skrev:

> From: Tom Wiltshire <tom at electricdruid.net>
> Subject: Re: [sdiy] VCO autotune for poly analog modular
> Date: Wed, 4 Apr 2007 15:27:40 +0100
> Message-ID: <758F5585-1BDC-4234-AF0F-E34B6A2B1A29 at electricdruid.net>
> 
> > 
> > On 4 Apr 2007, at 14:38, harrybissell at copper.net wrote:
> > 
> > > Should be easy to do by calibrating maybe five
> > > octave spaced points, then use linear interpolation
> > > within those note ranges. The Prophet V worked this way,
> > > and it was quite effective. That was a Z-80 iirc with very
> > > little RAM
> > >
> > > H^) harry
> > 
> > I second that. As others have said, you'd easily manage to do this  
> > with a modern uP. Storing a selection of points (octaves are an  
> > obvious choice, but you could go to half or quarter-octaves) and  
> > doing linear interpolation between them isn't too demanding. To make  
> > life easier, you could make sure the chip you use has a hardware  
> > multiply, since you'll need to multiply for the interpolation.
> 
> The trick is to make a calibration method in which the correction is cheap
> and where the calibration may take a few seconds but you generate the
> calibration data that makes the correction cheap. You do corrections much
> more
> often than calibration.
> 
> Cheers,
> Magnus
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> 



	
	
		
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