ST’s MEMS gyroscopes use two equal masses that are kept oscillating so that they are always moving in opposite directions, much like a tuning fork. When this system rotates, the Coriolis forces on the two masses are always in opposite directions, and the angular movement is measured using the difference in capacitance between the two sides. When a linear acceleration is applied to the sensor, both masses move in the same direction and the differential capacitance is zero. Compared to a single mass approach, the differential nature of the tuning fork makes the system intrinsically insensitive to undesired linear acceleration or vibration.