> > What do  you mean by "possible failure causes"?
> > For example are you trying to determine future reliability, like for a
> > space mission, or . .
> > do you have units that have failed and you want to know why, or . .

I'm seeing odd failure modes- suddenly, other frequencies appear in the
spectrum.  It only happens at a particular temp, which varies from one
osc to the next.  Above or below that temp, the effect vanishes.  Some
of them, the temp is above the operating range.  Others, it's right in
the room-temp ambient breadbasket (which is how we found it, of
course).

No one seems to know WHY this particular failure mode is occuring.
No one seems to know what the implication of this failure mode is
(i.e., if some of these slip through, is that a Portent of Doom for that
product, or will that oscillator last the effective lifetime of the device?).

> I'll bet Mike has a legitimate reason for asking. I have gone through a
> spate of bad crystals in the
> past, and the experience was NOT pleasant.

No, it isn't pleasant.  We can't tell if it's a process problem (handling,
baking, etc.) or a manufacturer defect in the parts.  Since nobody
knows why it's failing, we don't know where the flaw was introduced.

> You will notice that I no longer design-in crystals, I use ceramic
> resonators. And I have never regretted
> the change.

That would be nice, but I don't think 100MHz resonators are available.
Plus, we need more than .5% accuracy of frequency.

Mike H.
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