A three-axis capacitive accelerometer using an electrostatic servo sys
tem was developed. In this system, the acceleration is decomposed into
its axial components independently and simultaneously by using synchr
onous demodulation. To reduce the off-axis response, an electrostatic
force-balancing principle was used in order to keep the seismic mass i
n the original position. Typical results achieved for off-axis sensiti
vity were 1.3-7.3%.