SV: Re: SV: Re: [sdiy] Expo converters, lin log etc.

[Dave Manley]

Karl Ekdahl wrote:
> I've got some numbers of V->Hz that does not tell me
> anything really:
>
> Hz	V
> 342	0
> 365	1
> 396	2
> 451	3
> 533	4
> 650	5
> 834	6
> 1182	7
Normalize the data by subtracting 342 from all. You get this series:

0, 23, 54, 109, 191, 308, 492, 840 which is approximately:

0, 25, 50, 100, 200, 400, 800, 1600, with increasing error.

So... the series is roughly exponential:

23 * 2 = 56 ~= 54
54 * 2 = 108 ~= 109
109 * 2 = 218 ~= 191

In a VCO there is usually a trim-pot which adjusts the scale.

-Dave