National Instruments PXI-6561/6562 User Manual

Page 13

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© National Instruments Corporation


NI Digital Waveform Generator/Analyzer Guide

6. Enter values for the generation and acquisition voltages in the controls

below the Clock Frequency control. You can choose from standard logic
families (NI 654X/655X) or enter High and Low values to create your
own custom levels (NI 655X).

7. Choose a fill pattern. The following figure shows the pattern control and

the first few signals in the window.


When generating a Marching Ones or Marching Zeroes

waveform, it is convenient to make the waveform size a multiple of
the number of selected channels.

8. Click Play to generate the pattern shown in the graph on the selected

channels. The default generation option is Continuous, but you can
toggle this setting using the control below the graph.

The Play and Stop buttons are shown in the following figure.

Because the data channels on the NI digital waveform generator/analyzer
are bidirectional, while the data is being continuously generated on all of
the channels, as in the previous step, you can acquire the data being


Refer to the specifications for your device for information on

the setup and hold times and propagation delays associated with
generation and acquisition operations. At some frequencies,
generating and acquiring data on the same channels when no cable
is attached to the DIGITAL DATA & CONTROL (DDC) connector
violates these timing parameters and results in incorrectly sampled
data. For information on proper signal acquisition, refer to the
NI Digital Waveform Generator/Analyzer Help.

To acquire the pattern, complete the following steps:

1. Click the Acquisition tab.

2. Click Play. The device acquires the digital data that you generated in the

previous steps, and the data is displayed on the graph.

3. Click Close when you are finished.