116
Model 5380 PFPD Operator’s Manual
Rev. 3.1
In addition to ensuring accurate representation of noise, appropriate range and
attenuation settings will also limit the trade-off with the system’s dynamic range
available for monitoring signal output. In the example shown in Figure D.2,
selecting an attenuation of 16 would be counter productive because the additional
resolution would be obtained by reducing available dynamic range. Since the
output DAC has a maximum range of 65,535 counts, the tops of large output
signals are more likely to be truncated if lower attenuation settings are used.
Therefore, increasing the attenuation above 32 would undersample (and thereby
incorrectly display) the noise amplitude, while decreasing the attenuation below 32
would only reduce the dynamic range available for signal display. A general rule
for ensuring that there is enough resolution to observe true noise is to decrease
the attenuation until the observed noise level doubles.
A - Linear Vertical Scale
0.E+00
1.E-06
2.E-06
3.E-06
4.E-06
5.E-06
6.E-06
7.E-06
8.E-06
9.E-06
1.E-05
256
64
16
4
1
256
64
16
4
1
256
64
16
4
1
Attenuation
O
u
tput
Si
gnal
R
esol
u
ti
on (
A
m
p
s)
Range 100
Range 10
Range 1
B - Log Vertical Scale
1.E-15
1.E-14
1.E-13
1.E-12
1.E-11
1.E-10
1.E-09
1.E-08
1.E-07
1.E-06
1.E-05
256
64
16
4
1
256
64
16
4
1
256
64
16
4
1
Attenuation
O
u
tput
Signa
l R
e
s
o
lut
ion (
Log
Am
p
s
)
Range 100
Range 10
Range 1
Figure D.1. Effect of Range and Attenuation on Output Signal Resolution
Summary of Contents for 5380
Page 89: ...84 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 95: ...90 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 99: ...94 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 107: ...102 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 117: ...112 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 125: ...120 Model 5380 PFPD Operator s Manual Rev 3 1 Notes...
Page 133: ...P O Box 9010 College Station TX 77842 9010 Tel 979 690 1711 FAX 979 690 0440 www oico com...
