National Instruments NI 5401 用户手册

Chapter 1

Generating Functions with the NI 5401

©

 National Instruments Corporation

1-3

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:

 is the maximum output voltage level

 is the load impedance in ohms, and 

 is the output impedance on the NI 5401.

By default, R

 = 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

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,

. For 

specifications on the waveform output signal, see Appendix A, 

.

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 

+

-------------------

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