ODP: JH's VCO, wavetable source

[Roman Sowa]

AD775 can give you 20MHz 8-bit sample rate at about $18
Has reference inputs for lowest and highest conversion
voltage. There are also Texas Inst. versions of this chip.

Roman

> -----Oryginalna wiadomość-----
> Od:	Rene Schmitz [SMTP:uzs159 at uni-bonn.de]
> Wysłano:	6 lipca 1999 21:29
> Do:	synth-diy at mailhost.bpa.nl
> Temat:	RE: JH's VCO, wavetable source
> 
> The next question is how to ensure that no stored samples are skipped.
> I mean the adc could perhaps output one sample twice and then jump to two
> adresses above that. (Nonlinearity of the ADC.) Ok at low freq a minor
> problem (just a little THD).
> Then the next thing would be higher frequencies. I has been stated that
> the
> ADC0820 can be *clocked* at 400k but how many clock cycles does a
> conversion take? At least 8 or might even take 16. Assuming the conversion
> takes 8 cycles you'd have a sample rate of 50kHz. At 5kHz the cycle would
> consist of only 10 samples. You don't have the same time resolution as the
> output frequencies aproach the sample rate. Here the HSVCO would be
> better. 
> 
> Just a few random thoughts.
> 
>              ,   : (uzs159 at uni-bonn.de)
> |") [" |\ | ["   : (http://www.uni-bonn.de/~uzs159)
> |"\ [_ | \| [_   : (http://members.xoom.com/Rene_Schmitz)
>