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Hi, I'm [INAUDIBLE], an engineer
with National Instruments.

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In this video, we're showing
how you can configure

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phase coherent
measurement and generation

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systems using PXI Vector
Signal Transceiver and LabVIEW.

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In the hardware setup, we
have two PXI Vector Signal

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Transceivers, which are
both capable of generating

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and analyzing one gigahertz
of real time bandwidth.

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We perform the phase coherent
and measurement and generation

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in two steps, starting with
the alignment of the analyzers

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first.

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In the first step, here's
what the hardware connections

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look like.

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We're generating an RF signal
from one of the two VSTs

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and then feeding that
into a splitter, which

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splits the signal
into two signals

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and then feeds it into the
RF end of each of the Vector

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Signal Transceivers.

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Also, we'd like to make sure
that the local oscillators have

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been shared between the
generators and the analyzers

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of both of the VSTs.

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Now let's take a look at
the LabVIEW based example

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for phase coherent measurement
and generation systems.

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The first thing that
you'd like to do

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is to configure the
devices and make

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sure you have the right
frequency, reference level,

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and the initial phase offset.

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Then once you've
made sure that you

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have the right configuration
settings and both of the VSTs,

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click Run.

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As you can see in
the example here,

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we have an average
phase difference

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of almost 51 degrees.

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Because we've already made
sure that the generation is

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from a single generator and
they're using equal length

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cables, we can say for sure
that this phase difference

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is because of the mismatch
of phase in the analyzers.

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So we'd like to
align the analyzers.

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For that, click on this button.

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It gives you a prompt
of the hardware

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connection which
we've already made.

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So close that.

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Now once you've done
that, what happens

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is we're using the average phase
difference in the previous case

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as an initial phase offset
for one of the VSTs.

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And therefore, you see
that the phase difference

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between the two analyzers
is now zero degrees, which

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means that the analyzers
have been aligned.

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Now that you have your
aligned analyzers,

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you have a phase coherent
measurement system.

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The next step is to
align the generators.

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To do that, we'd have to change
the hardware connections.

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So for the next step,
which is alignment

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of the generators for phase
coherent generation system,

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we've connected the RF out
to RF in for both the VSTs.

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As far as the local oscillator
connection is concerned,

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it's the same as before.

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We've shared the
local oscillator

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between the generators and
the analyzers of the two VSTs.

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Now let's take a look at
the LabVIEW based example.

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As you can see here, we
have a phase difference

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between the two signals.

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And it's around
minus 23 degrees.

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We've already made sure that
our analyzers are aligned.

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We're also using equal
length cables for the RF out

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and RF in connection
of the two VSTs.

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So we can a certain from
that this phase difference is

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because of the mismatch of phase
between the two generators.

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To align the phase between
the two generators,

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we click on align generators,
a prompt comes up,

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it shows us the
hardware connections

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that need to be made.

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We've already done that.

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So let's close this.

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And now what happens is
we're using the average phase

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difference in the previous
step as an initial phase offset

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for one of the two VSTs.

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And that's how we get
a zero phase difference

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between the two signals.

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Now both our generators
and analyzers are aligned.

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And we have a phase
coherent measurement

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and generation system.

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So that's how we showed
how you can configure

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phase coherent
measurement and generation

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systems using PXI Vector
Signal Transceiver and LabVIEW.

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To learn more about an event
or a signal transceiver,

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log on ni.com/vst.

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