Acceleration-sensitivity is a vector, i.e., the acceleration-induced frequency shift is maximum when the acceleration is along the acceleration-sensitivity vector;
	It has been shown, empirically, that the acceleration sensitivity of a quartz crystal oscillator is a vector quantity. The frequency of an accelerating oscillator is a maximum when the acceleration is parallel to the acceleration-sensitivity vector.  The frequency shift is zero for any acceleration in the plane normal to the acceleration-sensitivity vector, and it is negative when the acceleration is antiparallel to the acceleration-sensitivity vector.
	Typical values of |G| for precision crystal oscillators are in the range of 10-9 per g to 10-10 per g.  |G| is independent of acceleration amplitude for the commonly encountered acceleration levels (i.e., at least up to 20g); however, high acceleration levels can result in changes, e.g., in the mounting structure, that can lead to G being a function of acceleration.  G can also be a function of temperature.
	The magnitude of the acceleration sensitivity is the vector sum (square-root of the sum of the squares) of the sensitivities along three mutually perpendicular axes.
	R. L. Filler, "The Acceleration Sensitivity of Quartz Crystal Oscillators:  A Review," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 35, No. 3, pp. 297-305, May 1988.
	J. R. Vig, C. Audoin, L. S. Cutler, M. M. Driscoll, E. P. EerNisse, R. L. Filler, R. M. Garvey, W. L. Riley, R. C. Smythe, and R. D. Weglein, "Acceleration, Vibration and Shock Effects - IEEE Standards Project P1193," Proc. 1992 IEEE Frequency Control Symposium, 763-781, 1992; also, The Effects of Acceleration on Precision Frequency Sources, U. S. Army Laboratory Command Research and Development Technical Report SLCET-TR-91-3, March 1991, AD-A235470.