[sdiy] oscillator auto calibration

[jean-pierre.desrochers at ville.quebec.qc.ca]

Thanks for your feedback Alan.

J-Pierre

-----Message d'origine-----
De : Needham, Alan [mailto:Alan.Needham at centrica.com]
Envoyé : 8 mai 2007 11:22
À : synth-diy at dropmix.xs4all.nl
Objet : RE: [sdiy] oscillator auto calibration


Assuming the PIC I/O pin will be calling an interrupt routine :-
As this will involve an undefined (and variable) response delay won't you
end up trading one error for another ?
Also, if this kind of accuracy is important, what will be the PIC chip's
timebase, a 100ppm crystal with its own temperature drift problems, the
XR2206 claims 20ppm/C anyway ?

Maybe discrete logic could be a better idea for the control loop but I still
wonder about a solid timebase.
Sorry if I am mis-interpreting your intentions here but, as interesting as
the idea is it seems a bit loose to me!

	Alan