Hello. My name is Kevin Cavell. I'm a product manager working for Agilent Technologies.
Today, I'm going to demonstrate using one of our new, higher power DC power modules
in our DC power analyzer mainframe. And in order to show you that, we’re going to be
testing a radio transceiver that I have here today. And we’re going to be doing three
measurements. We will do an off-mode current measurement, a standby current measurement,
and a transmit current measurement. And one of the benefits of the new N6764A module that
we have installed in the DC power analyzer mainframe is that it has two built-in current
measurement ranges a high range and a low range. So we can accurately measure the high-level
currents, as well as the low-level currents. So I have already set up the DC power analyzer
mainframe and the module installed to be set at 14.4 volts and 20 amps. The particular
module that is installed can source up to 60 volts and 20 amps, with a total output
power of 300 watts. Today, we will come a little close to that, you’ ll see. So the output,
right now, is off. So if I just turn the output on, we will see that we’re sourcing the 14.4
volts to the radio, and we’re seeing about 3.85 milliamps of current being drawn by the
device, even though you can see it is not powered on at all. So this is the off mode
or leakage current that the device will draw constantly, whether it is connected to a battery
or not. So if it is connected to a battery, you want to be careful. Because if you leave
this off for too long, you will actually drain that battery all the way to the end. So I
mentioned that this particular module has two built-in measurement ranges. In order
to get this very accurate, almost 4 milliamp measurement, we’re actually in the lower
measurement range. It is easy to change ranges just by going into the properties section.
And right now, I have it on Auto. That means that the range will be chosen automatically
by the module, depending on the output current. But you can see the other two ranges are 20
amps, as well as 500 milliamps. So depending on the accuracy you need, you can choose the
appropriate range. I'm going to turn it back to Auto because we will be going much higher
than 500 milliamps. If I go back to the meter view, again, we’re off. We’re pulling about
4 milliamps. If I turn the power on to the radio, you’ll see that with the radio on,
we have a steady state current of about 1.3 amps, and that equates to about 20 watts of
power that we’re sourcing to the radio, while it is just sitting here in standby. So it is
a pretty significant amount of power, just to be sitting here, without transmitting or
receiving. If we want to measure how much current is drawn when we’re transmitting,
all we have to do is click the microphone here, and we can see it jumps up to about
18 amps and 260 watts. I mentioned earlier that the module can go up to 300 watts, so
we’re using almost all the power that can be sourced by this particular module. So this
is a significant amount of power that is being drawn by the radio during transmit. So it is
very important, when you are testing something like this type of radio, or a military radio
that is going to be mounted inside of a vehicle and powered by a battery, or even military
radios that are larger, but powered by just a battery alone you want to be careful
about how much power is being drawn in off mode, in standby mode, and during transmit,
to make sure you get the most use out of that. So it is very easy to make these measurements
with the new N6764A module that we’re using today. Another thing I’d like to show you,
when testing a device that will be running off of vehicle power, is an alternator whine
test. What alternator whine is when the alternator is spinning, it could potentially
create a wave form that will be injected into the devices that are being powered off of
the electrical bus. And that wave form can cause problems with the device, or it could
bleed through the system and end up coming out of the speaker. We can simulate that test
using this system. The N6700 modules all have the ability to create wave forms. Even though
their power supplies can be used to create wave forms, the N6764 is one of our faster
modules, so it can create fast wave forms in the kilohertz range. So we will create that
now, very easily. Using the DC power analyzer, we can go into the arbitrary wave form setup
screen. You can see we have a choice of a few different wave forms. We’re going to
use a sine wave this time. If we go into the properties, you can see I have already created
my sine wave with a peak-to-peak voltage of a half a volt, so a quarter volt per side.
The DC voltage will be 14.4 volts, so we’re going to be riding that sine wave on top of
the 14.4. And the frequency of the wave form will be 1,000 hertz or 1 kilohertz. In order
to start this wave form and inject it into the radio, all we have to do is hit the Arb
Run/Stop key, and all of a sudden, you can actually hear the kilohertz sine wave coming
through the speaker. And I can start and stop it. So another interesting thing that we can
do with this system especially the N6764 modules they have dual digitizers that
are constantly measuring the voltage and the current of the output. And we can view the
information or the measurements that are being made by those digitizers in our scope view.
So if we wanted to see what the sine wave we created looks like, we can set up the scope.
It is very similar to an oscilloscope. We set the Run/Stop key. And if hit the Arb Run/Stop
key again, we can actually see the sine wave that we created. So I can stop it. Start it
up again. And you can hear the sine wave. If I hit the scope view key one more time,
that actually brings up the markers. And we could take some measurements if we wanted
to. And if I bring the markers to the peaks of one period of the wave form, we can actually
see, at the bottom here it is probably hard for you to see. But it says 980.4 hertz,
which is roughly 1 kilohertz. All right. So one other interesting thing we can do using
the scope view is earlier, we did a standby current measurement that was 1.3 amps, when
we turned on the radio and just let it sit there without transmitting. Typically, when
you first turn on an electrical device, there’s some in-rush of current. And that can be very
high. So we can actually measure that using the scope view here. So let’s do that. We will
turn the radio off, and I’ll set up to measure the current in scope view. So I just need
to go in and change my trigger levels from voltage to current. So I'm changing from voltage
of Channel 1 to current of Channel 1. And my trigger level is set to 2 amps. So if we
go back to the scope view, we’re all set up. We just press the Run/Stop key. It is
lit, so that means it is waiting for a trigger. And if I hit the power on, we can actually
see that we captured that in-rush current, that peak of current. As it shoots up, the
current rushes into the device, and then it starts to settle. So you can see we don’t
see it settle all the way down. So if I just change my time base, you can see it better.
We can actually retake this measurement real quickly and see a more complete wave form.
So there’s the in-rush current. If we want to know how high this peak is, again, we could
turn on the markers by pressing the scope view key again, and then move the markers
around that point. And in the corner here, you can see that maximum is 5.5 amps of in-rush
current. So a little bit higher than the 1.3 steady state, but not too high. In some cases,
with certain devices, you’ll see a certain amount of in-rush. But here, you see about
5.5 amps. So, again, it is a very easy way to make very complicated measurements. Usually
you have to have a pretty sophisticated setup with an oscilloscope, a DMM, a current probe.
Here, we have it all in one system. And with the advanced capabilities of the different
modules that you can put into the mainframe, it makes making these types of measurements
very easy. Thank you.