Hello.
My name is Chris Behnke, an offering manager
in the aerospace and defense business unit at NI.
Phased arrays are becoming an important RF architecture
in aerospace and defense applications,
such as radar and satellite communications.
The components and modules used to build these architectures
have unique RF characterization requirements that
need to be performed to ensure the end system
will perform correctly.
As such, NI has released the Electronically Scanned Array
characterization reference architecture, or ESA reference
architecture for short, which includes all the necessary IP
to perform these measurements.
In this video, we will show you how
to perform pulse profile and pulse-to-pulse stability
measurements using the NI Vector Signal Transceiver, or VST.
To characterize PAs, or Power Amplifiers,
and transmit and receive models for radars,
it is important to be able to perform
pulse measurements, such as pulse profile
and pulse-to-pulse stability.
Pulse profile, for example, is looking at a single pulse
and ensuring that the various attributes are correct,
such as state levels, transition durations, overshoot
and undershoot, droop, or ripple and ringing.
A secondary measurement used to qualify
the performance of a component in a radar
is pulse-to-pulse stability.
This can either be the stability of pulses
over an entire chain of pulses, or the stability of samples
within a single pulse.
In this measurement, you're looking
at the stability of both magnitude and phase over time
and temperature to ensure that the component or module itself
will behave over the operational mission of the end system.
The challenges of pulse profile and pulse stability
measurements include the synchronization of RF pulse
stimulus with a DUT, Device Under Test,
you're controlling to accurately characterize
the component stability.
The dynamic range and phase noise of instrumentation
can negatively affect measurement accuracy.
And the limited RF instrumentation bandwidth
can reduce your test coverage and ability
to meet the needs of more advanced radar applications.
Using the pulsed RF measurement library included within the ESA
reference architecture, we will show you
how to overcome these test challenges
and measure both of these parameters accurately.
Here, we see the interactive example for pulse measurements,
including the pulsed RF measurement
library within the reference architecture.
In this setup, we will be providing a pulse stimuli
to an X-band transmit and receive module typically found
in the front end of a radar phased array.
We will perform not only pulse profile measurements,
but the pulse-to-pulse stability measurement itself
simultaneously using the Vector Signal Transceiver, or VST.
As for all of the interactive examples within the library,
you are provided the ability to both configure the hardware,
as well as the stimulus and measurement,
as well as in real time, view the measured results
for interactive analysis.
In this particular case, we're using the vector signal
transceiver and a shared LO configuration.
This allows us to optimize out the phase noise
impact of the instrumentation itself,
and therefore, tackle one of the key challenges
of these measurements.
This is configured using the panel on the left here,
which allows us to select the VST,
as well as configure the synchronization and LO sharing.
In this case, we're tuned to 10 gigahertz, which
is at the top end of X-band.
You can also configure the stimulus
based on things like pulse repetition interval, pulse
duration, and the sample rate of the device itself.
We support CW, as well as other stimuli types within the pulse
library.
However, in this case, we're using CW for a simple stimuli.
Trigger settings can also be configured,
allowing you to either control the synchronization
with devices under test, or take in a triggered result
from the device itself, again, tackling
one of the key challenges for this measurement.
And then, finally, you can choose
the specific configuration types for the particular
measurements, such as your pulse profile
and pulse-to-pulse stability.
This includes setting where the samples will
be within the pulse to provide your statistical results.
Once you're satisfied with the configurations of the hardware
and the software, you can go ahead and run the measurements,
as you see happening right now.
Within the displayed measurements,
you see multiple displays that can be
configured based on your needs.
In this case, we're looking at the pulse-to-pulse stability
plot, which includes information on the stability of phase,
magnitude, and the overall results.
You can also look at things such as the amplitude profile, which
shows you the pulse profile from the first measurement, as well
as the statistical results, such as droop, rise time, width, et
cetera.
Finally, we have supplementary views
to show you additional parameters, such as the FFT
of the pulsed stimuli itself, and the instantaneous values
of the measured samples within the pulse
for pulse-to-pulse stability.
Once you're satisfied with the measurements, or in fact,
as you're measuring the experiment,
you can record the data for post-processing
at a later time.
This completes showing the demonstration of pulse
measurements and pulse-to-pulse profile using
the interactive example within the pulsed RF measurement
library in our reference architecture.
As you've seen, we've tackled the challenge of pulse profile
and pulse stability measurements,
in particular, the synchronization of RF stimulus
with the DUP, the instrumentation phase noise
degradation, and the limited RF instrumentation bandwidth
simply by using the benefits of the vector signal transceiver.
Combining these advantages with our software-defined
measurements allows you to tackle the overall test plan
and requirements for your PA or transmit and receive module
in our radar application.
For more information on pulse profile measurements
and pulse-to-pulse stability, as well as the ESA reference
architecture, please visit NI.com.
Thank you very much.
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