CMA3000-D0X Datasheet, PDF (29/35 Pages) VTI technologies – 3-axis accelerometer

Equation 7
( ) n =
1
3
n_X²
+ n_Y² + n_Z²
,
CMA3000-D0X Series
where n is sensor’s noise [g] per axis, n_X is sensor’s X-axis noise [g], n_Y is sensor’s Y-axis noise [g]
and n_Z is sensor’s Z-axis noise [g].
CMA3000 demo-kit design can be used as a reference design for noise measurements, refer to
“CMA3000 DEMO KIT User Manual 8288400”.
8.5 Bandwidth
Signal bandwidth is measured in a shaker by sweeping the piston movement frequency with
constant amplitude (Figure 22).
Z
Y
X
Shaker
movement
in parallel
to Z-axis
Earth’s
gravitation
Pin #1
Figure 22. CMA3000 movement in Z-axis bandwidth measurement.
8.6 Cross-axis sensitivity
Cross-axis sensitivity is sum of the alignment and the inherent sensitivity errors. Cross-axis
sensitivity of one axis is a geometric sum of the sensitivities in two perpendicular directions.
Cross-axis sensitivity [%] of X-axis is given by
Equation 8
Cross_X = ±
S _XY ² + S _XZ ² _⋅100%,
S_X
where S_XY is X-axis sensitivity to Y-axis acceleration [Count/g], S_XZ is X-axis sensitivity to Z-axis
acceleration [Count/g] and S_X is sensitivity of X-axis [Count/g].
Cross-axis sensitivity [%] of Y-axis is given by
Equation 9
Cross_Y = ±
S_YX ² + S_YZ ² _⋅100%,
S_Y
where S_YX is Y-axis sensitivity to X-axis acceleration [Count/g], S_YZ is Y-axis sensitivity to Z-axis
acceleration [Count/g] and S_Y is sensitivity of Y-axis [Count/g].
Cross-axis sensitivity [%] of Z-axis is given by
VTI Technologies Oy
www.vti.fi
Doc.Nr. 8281000.12
29/ 35
Rev. 0.12