CLIENTS user guide SA1000
Page 18
Error distribution (% of frequencies)
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
-6.00
-4.00
-2.00
0.00
2.00
4.00
6.00
Deviation (dB)
P
e
rc
e
n
t
s
c
a
n
r
e
a
d
in
g
s
B,D,H,J
C, E, F, K
D, F, I, M
Figure 11
This shows the error distribution for each of the three tests above.
The percentage of results within 2dB of the actual is 89.96%, 87.91% and 92.83% respectively
and within 3dB the figures are 96.31%, 97.34% and 97.34%. This shows that the choice of
locations within the volume will have an effect on the results, but as figure 6 graphically shows,
the effect is marginal. Taking more that 4 scans (4 locations) will improve the results, but the law
of diminishing returns will apply.
All the above tests have been undertaken with a compact source (the ERS). An EUT with cables
or larger distributed sources would increase the measurement uncertainties. The degree of
increase is entirely dependant on the detail of the EUT, cables and the rigour with which the
testing is accomplished.
