National Instruments NI 6120 用户手册

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

 in Figures 4-2 and  4-3.

+

–

V

m

100 pF*

1 M*

50 

Ω

0.1 

µF

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

+

–

+

–

+

–