Chapter 2
NI 5450 Overview
NI PXIe-5450 User Manual
2-64
ni.com
Streaming
Streaming is a way to generate waveforms that are too large to fit in the
onboard memory of the signal generator. Streaming can be used in
Arbitrary Waveform, Arbitrary Sequence, or Script output modes.
To stream waveform data, allocate and identify all or a portion of the signal
generator onboard memory to act as an onboard waveform for streaming.
Before initiating waveform generation, fill that onboard memory with the
first part of your waveform. As the waveform is generated, space in the
onboard memory becomes free and fill that space with new waveform data.
Repeat the process of filling the freed onboard memory in blocks of new
waveform data until the waveform is complete.
Streaming Waveform Data
The following instructions are a guide for configuring your application for
streaming. For a programmatic example, refer to
Fgen Arb Waveform Streaming.vi
for LabVIEW or
ArbitraryWaveformStreaming.prj
for LabWindows/CVI.
As an example, we have a 1.6 GB waveform we want to generate and an NI
arbitrary waveform generator with 256 MB of onboard memory. This
1.6 GB waveform may be in the host memory, on disk, or data that your
application generates dynamically during generation.
1.
Specify the amount of onboard memory to be used for
streaming
—Call the niFgen Allocate Waveform VI or the
niFgen_AllocateWaveform
function to specify the amount of
onboard memory to reserve for streaming. The allocated memory,
known as the
streaming waveform
, serves as a buffer for the streaming
256 MB On
b
o
a
rd
Memory of NI 5421
1.6 GB W
a
veform
