4-80
The frequency excursion during a shock is due to
the resonator’s stress sensitivity.  The magnitude of
the excursion is a function of resonator design, and
of the shock induced stresses on the resonator
(resonances in the mounting structure will
amplify the stresses.)  The permanent frequency
offset can be due to: shock induced stress
changes, the removal of (particulate) contamination
from the resonator surfaces, and changes in the
oscillator circuitry.  Survival under shock is primarily
a function of resonator surface imperfections. 
Chemical-polishing-produced scratch-free resonators
have survived shocks up to 36,000 g in air gun tests,
and have survived the shocks due to being fired from
a 155 mm howitzer (16,000 g, 12 ms duration).
Shock
3
2
1
0
-1
-2
-3
tO
t1
Shock
   See chapter 5 for further information about the etching and chemical polishing of quartz crystals.
   The shock testing of a frequency source generally consists of measuring the frequency or phase of the source before and after exposing the device to the specified shock.  The phase deviation resulting from the shock (which is the time integral of the fractional frequency change) can provide useful information about the frequency excursion during the shock (including the possible cessation of operation).


R. L. Filler, L. J. Keres, T. M. Snowden, and J. R. Vig, "Ceramic Flatpack Enclosed AT and SC-cut Resonators," Proc. 1980 IEEE Ultrasonic Symp., pp. 819-824, 1980.

J. R. Vig, J. W. LeBus, and R. L. Filler, "Chemically Polished Quartz," Proc. of the 31st Ann. Symp. On Frequency Control, pp. 131-143, 1977