National Instruments PXI NI 5401 - Manual (Page 10)

Chapter 1 Generating Functions with the NI 5401
© National Instruments Corporation 1-3 NI 5401 User Manual
ARB Connector
The ARB connector provides the waveform output. The maximum output
levels on this connector depend on the type of load termination. If the
output of your NI 5401 terminates into a 50
Ω
load, the output levels are
±5 V, as shown in Figure 1-2. If the output of your NI 5401 terminates into
a high-impedance load (HiZ), the output levels are ±10 V. If the output
terminates into any other load, the levels are as follows:
where V
out
is the maximum output voltage level
R
L
is the load impedance in ohms, and
R
O
is the output impedance on the NI 5401.
By default, R
O
= 50
Ω
, but you can use your software to set it to 75
Ω
.
Figure 1-2. Output Levels and Load Termination Using a 50
Ω
Output Impedance
Note Software sets the voltage output levels based on a 50
Ω
load termination.
For more information on waveform generation and analog output
operation, refer to Chapter 2,
Function Generator Operation . For
specifications on the waveform output signal, see Appendix A,
Specifications .
SYNC Connector
The SYNC connector provides a TTL version of the sine waveform being
generated at the output. You can think of the SYNC output as a very
high-frequency resolution, software-programmable clock source for many
applications. You can also vary the duty cycle of the SYNC output on the
fly by software control, as shown in Figure 1-3. t
p
is the time period of the
V
out
R
L
R
L
R
O
+
------------------- 10
×
V
±
=
ARB
NI 5401
Load
±5 V R
L
=
50
Ω
50
Ω
Load
R
O
=
50
Ω
ARB
NI 5401
Load
±10 V
R
L
=
HiZ
High-Impedance Load
R
O
=
50
Ω