[sdiy] Unstability ..err.. instability of oscillators and psychoacoustic qualities

[phillip m gallo]

" I'd be very curious about the difference between a warm analog VCO and a
DCO."

If you'll allow the play on words, i would compare a "warm" VCO with a
"cold" DCO.  Because this is one of the perceptible advantages of a decent
DCO it's "on freq" now.

But humor aside, you can calculate the expected "best case" jitter of a DCO.
The DCO varies from this "ideal" as a function of it's implementation.
DCO's that use counters have jitter resulting from the freq standard and the
timing chain.  Usually the challenge for Timer based DCO's is the ultimate
Freq. Accuracy.

Phase accumulators show jitter relative to the Freq. Standard, Freq.
emitted, the width of the accumulators, and sample rate.

As to the instability of VCO's i suspect that the "warm"/"cold" property, if
demonstrable at all (in correlation) is perhaps, only partially indicated by
"real time" instability and probably not at all by "long term" instability
which is the real rub with a VCO.  But your investigation might show
otherwise.

What ever warm/cold is i would wonder if the same oscillator would be
identifiably when observed individually and in concert with other identical
oscillators.  Also, does it sound "warmer" or " "colder" in the dark or
light.  What would the results be if you said to your test subjects "First
let's test the "warm" oscillator, now we test the cold one".

Sounds like an interesting inquiry.

regards,
p

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