User`s manual

Hardware Information 27
USB-1900 Series
Figure 2-16: GRND-Referenced Sources w/ NRSE Inputs
Pseudo-Differential Input Mode
Pseudo-differential input mode provides positive signal and
negative signal inputs that respond to signal voltage difference
between them, with the negative signal at a constant potential,
as shown. If the signal source is ground-referenced,
psuedo-differential mode can be used for noise rejection for
improvement over single-ended mode.
Figure 2-17: GRND-Referenced Source w/ P-D Input
A
IxH
A
IxL
x
= 0, ..., 7
Ground
Referenced
Signal
Source
To A /D
Converter
A
IGND
+
-
Instrumentation
A
mplifier
V
cm
Common-
mode noise &
Ground
potential
+
-
Input Multiplexer
A
IxH
A
IxL
x = 0, ..., 7
Ground
Referenced
Signal
Source
Instrumentation
Amplifier
+
-
To A/D
Converter
A
IGND
+
-
Input Multiplexer