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using existing instrumentation.
Modular and Easily
Synchronized
Modern communications standards
ranging from Wi-Fi to mobile use
sophisticated multiantenna technology.
In these systems, MIMO configurations
provide a combination of either higher
data rates through more spatial streams
or more robust communications through
beamforming. Because of these MIMO
benefits, next-generation wireless
technologies like 802.11ax, LTE-
Advanced Pro, and 5G will use more
complex MIMO schemes with up to 128
antennas on a single device.
Not surprisingly, MIMO adds a lot of
design and test complexity. It not only
increases the number of ports on a
device but also introduces multichannel
significant improvements in instrument
performance simply by moving closed-
loop control, measurement acceleration,
real-time signal processing, or
synchronous device under test control
on the instrument itself.
One application that software-designed
instrumentation can uniquely solve is
radar prototyping. In this application,
customers can use the FPGA as a
complete target simulator. In radar
applications, a radar system detects
a “target,” such as an automobile,
airplane, or other object, by sending a
stimulus signal and then waiting for the
response. Attributes of the stimulus’
reflection off the target, such as the delay
and frequency shift, indicate both the
distance and velocity of the target. The
combination of the VST’s wide bandwidth
and user-programmable FPGA makes it
ideal for target emulation. In addition,
engineers can easily customize the FPGA
to modify the types of targets they need
to simulate.
Part of a Platform
One of the most important features of
the VST is that it is part of a complete
hardware and software platform. In the
current era of smart, connected devices
and ICs, modern test instrumentation
has transitioned from discrete
instruments to highly integrated test
systems. As a result, meeting the latest
measurement challenges like envelope
tracking PA test and radar prototyping
requires a platform of instruments that
can be synchronized, customized, and
easily controlled with software.
Although the next wave of wireless
technologies, from 5G to 802.11ax, will
introduce significant design and test
challenges, NI’s second-generation VST
was created explicitly to address them.
With wider bandwidth, a smaller form
factor, excellent RF performance, and
software customizability, the VST is
scalable to meet the most difficult test
challenges today and tomorrow.
synchronization requirements. To test a
MIMO device, RF test equipment must
be capable of synchronizing multiple
RF signal generators and analyzers. In
these configurations, the instrument’s
form factor and the synchronization
mechanism are critical.
Fortunately, the second-generation
VST is small enough that engineers
can synchronize up to eight VSTs in a
single 18-slot PXI chassis with one slot
dedicated to a PXI controller.
Designed by Software
A final requirement of next-generation
wireless test systems is that engineers
can design themwith software. Advanced
wireless test applications increasingly
require engineers to tailor the behavior
of the instrument’s firmware. In these
applications, engineers can experience
Figure 5. Radar System Block Diagram with Custom mmWave
Head
Figure 4. Typical 8x8 MIMO System with 8 VSTs
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