G or acceleration sensitivity is a measurement of the sensitivity of a crystal oscillator to acceleration, anddescribes a short-term or instantaneous frequency error.A crystal oscillator subject to acceleration or mechanical shock has a slightly different series resonantfrequency than the same oscillator experiencing no acceleration. It has been observed that the magnitude ofthe frequency shift is proportional to both the magnitude and the direction of the acceleration relative to acoordinate system applied to the crystal. [2]A representation of this effect can be considered in the case of a crystal subject to a cycle of acceleration at arate of fV :