SCA3000 Series
where Output@acc is sensor’s nominal output [counts] with input acceleration acc in [g], Output+1g is
sensor’s measured output [counts] at +1 g input acceleration and Output-1g is sensor’s measured
output at -1 g input acceleration. Possible offset term [counts] is included into nominal output,
because it is not included in to linearity error.
8.4 Noise
Output noise nX, nY and nZ in X,Y and Z directions is the measured standard deviation of the output
values when the sensor is in 0 g position at room temperature. Average noise/axis is calculated by
Equation 9
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].
SCA3000 demo-kit design can be used as a reference design for noise measurements, refer to
“SCA3000 DEMO KIT User Manual 8259300”.
8.5 Bandwidth
Signal bandwidth is measured in a shaker by sweeping the piston movement frequency with
constant amplitude (Figure 24).
Z
Shaker
Earth’s
gravitation
movement
in parallel
to Z-axis
Y
X
Pin #1
Figure 24. SCA3000 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 10
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
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