[time-nuts] Xtal Oscillator Aging
Luis Miguel Brugarolas
lmbruga at ieee.org
Sat Oct 20 14:13:53 EDT 2007
At Sunday, October 23, 2005 9:21 PM, Tom Clark wrote:
> Going in the other direction, the mechanical resonant frequency
> changes with time because, as the xtal vibrates, microscopic cracks in
> the structure of the quartz break apart. Running at high power makes
> the crystal generate these microscopic faults at a faster rate; this
> then causes the oscillator to have poorer long-term stability. When an
> xtal is left vibrating (oscillating) in an undisturbed environment,
> the rate of cracking of the quartz decreases, and the oscillator is
> said to "age" to its final frequency.
> But if you subject that same crystal to a mechanical jolt will force
> some new cracks and re-start the aging "diffusion" process. Ditto
> turning the oscillator on & off or a thermal shock can aggravate the
Could someone confim or deny an idea I posted some weeks before about ageing
is more predictable on free running oscillators than in disciplined ones?.
I read about it in a Simetricomm datasheet some time ago, but I would like to
know experimental or theoretical explanation for that (or the contrary).
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