[sdiy] Interesting f vs. t graphs of pitch instability

[cheater cheater]

I think you just need to oversample 64x or something crazy like that.

D.


On Tue, Mar 9, 2010 at 07:54, Andre Majorel <aym-htnys at teaser.fr> wrote:
> On 2010-02-20 10:37 -0800, David G. Dixon wrote:
>
>> > Finally fixed it. It wasn't VR4, it was the CA3140 (IC5).
>> > Replacing it made the wavering go away.
>>
>> Andre, I recall our discussion about VCOs vs DCOs and how you
>> thought the former might sound better than the latter because of
>> slight frequency noise.  It would be interesting to see whether
>> there is any measureable noise now that the unit is fixed.
>
> Thought you might catch on that. :-) The graph you're looking for
> is already there, it's number 3 (ms20_pitch_instab_ext_volt.flac)
> in http://www.teaser.fr/~amajorel/ms20/files/waver1.png
>
> But I suspect that any short term deviations lesser than 6 Hz tell
> you more about my frequency counter than they do about the signal.
> See my answer to Magnus on 2010-02-20 for the reason why.
>
> To measure frequency jitter of that magnitude, I think you'd need
> a much higher sample-rate / signal-frequency ratio and/or a much
> better frequency counter.
>
> It is interesting, however, that there is no frequency noise to
> speak of on the mathematically generated sawtooth (bottom right
> graph). So perhaps there is a way...
>
> --
> André Majorel http://www.teaser.fr/~amajorel/
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