CMA3000-D0X Series
Equation 7
1
n =
(
nX2 + nY2 + nZ2
)
,
3
where n is sensor’s noise [g] per axis, nX is sensor’s X-axis noise [g], nY is sensor’s Y-axis noise [g]
and nZ 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
Shaker
Earth’s
movement
gravitation
Y
in parallel
X
to Z-axis
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
2
SXY 2 + SXZ
CrossX = ±
⋅100%,
SX
where SXY is X-axis sensitivity to Y-axis acceleration [Count/g], SXZ is X-axis sensitivity to Z-axis
acceleration [Count/g] and SX is sensitivity of X-axis [Count/g].
Cross-axis sensitivity [%] of Y-axis is given by
Equation 9
2
SYX 2 + SYZ
CrossY = ±
⋅100%,
SY
where SYX is Y-axis sensitivity to X-axis acceleration [Count/g], SYZ is Y-axis sensitivity to Z-axis
acceleration [Count/g] and SY is sensitivity of Y-axis [Count/g].
Cross-axis sensitivity [%] of Z-axis is given by
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