National Instruments NI 6115/6120 User Manual page 47

Chapter 4 Connecting Signals
Ground-
+
Referenced
V
s
Signal
–
Source
Common-
+
Mode
V
Noise and
cm
Ground
–
Potential
NI 6115/6120 User Manual
ACH0+
ACH0–
High-Frequency
Common Mode Choke
ACH0GND
50 Ω
Figure 4-3. Pseudodifferential Input Connections on the NI 6120
With this type of connection, the PGIA rejects both the common-mode
noise in the signal and the ground potential difference between the signal
source and the device ground, shown as V
AC Coupling
+
100 pF* 1 M*
–
*10 kΩ40 pf
0.1 µF
for Ground-Referenced Signals
cm
4-10
Instrumentation
Amplifier
PGIA
+
Measured
V
Voltage
m
–
for ranges > ±10 V
in Figures 4-2 and 4-3.
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