Chapter 2
NI 5450 Overview
NI PXIe-5450 User Manual
2-4
ni.com
Differential Channel Connectors
The CH 0+/
−
and CH 1+/
−
connectors are the analog waveform output
terminals. These connectors provide differential waveform output; they
cannot be used for single-ended operation. The connectors must terminate
into balanced loads. The maximum output levels from these connectors
depend on the type of load termination. For example, if the output of the
device terminates into a balanced 50
Ω
load with flatness correction
disabled, the maximum output levels are ±0.5 V, while the maximum
output levels are ±1.0 when the device terminates into a high-impedance
load (HiZ). This difference is illustrated in the following figure.
If the output terminates into any other load, the levels are defined by the
following formula:
V
out
= ± [
R
L
/ (
R
L
+
R
O
) ] × 2 V
where
V
out
is the maximum peak output voltage level
R
L
is the load impedance in ohms
R
O
is the output impedance of the module in ohms
Note
For loads less than 50
Ω
, load impedance compensation supports only combinations
of gain and load impedance that meet the previous V
out
equation.
Set the amplitude of the generated output signal in terms of peak voltage by
setting the gain value. NI-FGEN calculates and sets the correct amount of
attenuation required for the desired gain value. Configure the output signal
NI 5450
Load
R
L
=
50
Ω
50
Ω
Load
R
O
=
50
Ω
R
L
=
50
Ω
R
O
=
50
Ω
±0.5 V
+
-
NI 5450
Load
R
L
=
HiZ
High-Impedance Load
R
O
=
50
Ω
R
L
=
HiZ
R
O
=
50
Ω
±1.0 V
+
-
