Chapter 4
Connecting Signals
4-10
ni.com
Figure 4-3.
Pseudodifferential Input Connections on the NI 6120
for Ground-Referenced Signals
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
cm
+
–
V
m
100 pF*
1 M*
50
Ω
0.1
µ
F
High-Frequency
Common Mode Choke
ACH0+
ACH0–
ACH0GND
PGIA
Instrumentation
Amplifier
*10 k
Ω
40 pf
for ranges > ±10 V
Ground-
Referenced
Signal
Source
AC Coupling
Common-
Mode
Noise and
Ground
Potential
Measured
Voltage
V
s
V
cm
+
–
+
–
+
–