[sdiy] Yusynth VCO

[yves usson]

Hi Ian

By 5 cents I referred the musical cent(those shown on a chromatic 
tuner), that is the drift is hardly audible (at least to me).
All these figures I gave them from memory since these measurements were 
performed 4 years ago.
As a follow up to your question I searched my archives and hopefully 
retrieved the spreadsheet file
with these measurements.
Here is what I had :
I ran two set of measurements.

The first one over five hours and 2à minutes at room temperature, I 
measured the frequency and room temperature at roughly
equally spaced time. The initial frequency was 881Hz and initial 
temperature 22.2°C, the final frequency was 877.5Hz and
final temperature of 23.7°C.
The slope of the measurement curve gave me a drift of -2.27Hz/°C that is 
-0.05%/°C or -500ppm/K (if I am correct ?)

The second set was run at a constant temperature of 23.3C over 80 
minutes, the measured detune was 0.5Hz that is
roughly 2 cents.

I hope this will satisfy your curiosity ;-)

Cheers

Yves

Ian Fritz a écrit :
> At 03:37 AM 4/4/2010, yves usson wrote:
>> ... the tests I ran gave a excellent V/OCT tracking from 16Hz up to 
>> 6.5kHz
>> (roughly 8 octaves) and then started to slightly degrade.
>> For thermal stability, I measured a deviation of 5 cents over 2 hours 
>> with a room temperature change of  2.5°C.
> 
> Thank you.  From that I calculate a drift of 1100 ppm/K -- is that correct?
> 
> Ian
>