Hi and welcome to scope month! My name
is Daniel Bogdanoff. Today is Wednesday,
March 15th which means we are going
to give away another six 1000 X-Series
scopes. Normally we'd only give away five,
but someone posted on Twitter a picture
of the cutout at Embedded World so we're
going to give away an extra five 1000 X-Series
scopes. We're going to give away one
per day- Wednesday, Thursday, Friday, and
then we're going to give away two in the
live stream on Monday. So make sure you
go over to the Keysight Oscilloscopes
youtube channel home page and you can
get a reminder for that live stream. For
today's scope tip we're going to look at
the frequency response analysis
capabilities on the 1000 X-Series scopes
with Johnnie Hancock, and Johnnie is
actually at Embedded World with Mike
Hoffman this week so if you are there
make sure you stop by and say hi to Mike
and Johnnie, snap a picture, throw it on
our Facebook page. Maybe we'll post them
in later videos. So we pre-recorded the
tip with Johnnie last week while he
was still here in Colorado Springs. Let's
take a look. For today's scope tip I've
brought in Johnnie Hancock. Johnnie come on
out. Johnnie's going to step up on some
books here. So Johnnie what are you here
to talk about today? [Johnnie] We're here to talk
about frequency response analysis which
is a standard feature on the G models of
the 1000 X-Series oscilloscope. [Daniel] And this
is kind of your brainchild, Johnnie. Like I
said in the live stream, you've been
pretty instrumental in making this
happen. [Johnnie] That's true and something went
wrong in the live stream. I got the
channels assigned backwards. But we're going to
get it right today. [Daniel] Sounds good. Let's
take a look. [Johnnie] ok so first of all frequency
response analysis testing gives you a
different view of the performance of the
circuit as opposed to traditional time
domain waveforms, shows you things
in a frequency domain and it plots gain
& phase versus frequency- so V-out over
V-in but logarithmically so 20 log V-out
over V-in. So I'm going to start with
the default setup and I already have my
low pass filter is just a simple RLC
circuit connected to the output of the
wave gen, channel one connected to the
input, channel two connected to the
output which is in this case a bandpass
filter. First I'm going to select the
"analyze" menu, then select the "frequency
response analysis," then I could go into the
setup menu. There I get a diagram showing me
basically a block, so you're testing a
black box. And we have V-input,
V-output plus we have to connect the
generator to stimulate it at the input.
We can assign which channel's channel 1,
which is channel 2. I'll make sure I
don't bump any knobs this time. Minimum
frequency, it can go down to 20 Hz.
Let's go ahead and test at the extreme
and up to 20 Mhz. We'll just leave
it there and then you can set the test
amplitude. Now sometimes that's a
sensitive setting. It really depends on
what you're testing. If you're testing
power supplies, sometimes they can be
over driven. We're just going to use the
default for this passive filter, it's not
very sensitive. Now the amplitude,
this is in volts peak-to-peak. Now most
standalone frequency response analyzers
or network analyzers typically
have them set in either voltage RMS or
DBM so you just need to do the
conversion if you're going to compare
apples to apples. So we'll press the back
key and the next thing is just press "run
analysis." Now one big advantage of the
Keysight oscilloscope based solutions is
you can see the waveforms during the
test. The yellow waveform is V-in, the
green waveform is V-out. It started down
here, you can see it
plotting gain down there close to
-50 dB. Now the spec is as much as
approximately 80 dB, so the orange trace
is the phase. Now when it completes the
test and we're about two thirds through
now. As you go in the higher frequencies
the test runs faster and faster. It runs
pretty slow down there at 20 Hz. [Daniel] And
it'll change based on the settings that
you have for the minimum and maximum
frequencies- the test time will. [Johnnie] That's
correct. Yeah if you start at higher
frequencies it's going to run a lot
faster. [Daniel] So naturally you would just test
the frequencies that you care about, not
necessarily run the whole spread. [Johnnie]So here
we see the final plot, so again you can
see it started- well let's go ahead and
use the markers- you can see there's
a pair of markers- one writing the phase
curve which this shows you the phase on
the right hand scale and the gain in dB
is on the left hand scale. Now the marker
readout is down here. Now the minimum was
-44.7 dB and we could take it up
here. We might want to lock it in around
-3 dB if we're going to measure the
bandwidth and then we go out to the
maximum. So you can measure any gain
& phase at any particular frequency. It
also auto scales the scaling of both the
gain & phase plot at the completion of
the test. So it's giving you optimum
scaling but you can manually change it
if I go into the chart, I could select
"gain scale" and change that or "gain
offset" and then I could do the same
thing with the phase plot as well.
[Daniel] Awesome! Thank you very much, Johnnie.
So the FRA is included standard with all
the G models. We are really, really
excited about it. Johnnie has worked
really hard to make this happen so if
you liked it, give Johnnie a little round
of applause. There's also a
webcasts that Johnnie did that you can go
check if you want to learn more about
measuring frequency response with
oscilloscopes. [Johnnie] Yeah one other thing, you
may be wondering, you may be aware that
the 3000 X and 4000 X, this guy's big
brothers and sisters, also can do
frequency response analysis as part of
the power application. They're called
power supply rejection ratio and control
loop response. It is a superset of this.
This is kind of a subset. It has more
features. You can do amplitude profiling.
You can select more points per decade
for your test run. You can also get a
tabular view of the results. This you
only get the plot view, which is pretty
darn good for what you're paying for
this particular product. [Daniel] Absolutely!
Alright, thanks, Johnnie! [Johnnie] Thanks! [Daniel] So if you're at
embedded world this week go say hi to
Johnnie and Mike. Also you can check out
the new blog on the Keysight Oscilloscopes
blog. There's a link for that in the
description. So now let's draw today's
six 1000 X-Series scopes winners
Today's winners are Daniel Nubling,
Niklas Bark, Craig Chatterton, Stephen
Graf, Dan Ursu, and Zacher Jeffrey.
Congratulations especially to the people
named Daniel! If you've won a scope, we
should be in touch with you within six
business days. That's all for today. Make
sure you subscribe to the YouTube
channel, go check out the Keysight Oscilloscopes
blog. Thanks for watching and I'll
see you tomorrow!
Now Daniel, this is so
easy even a dummy, like you standing here
next to me, could do. You may be wondering
why I am almost as tall as you for the
first time in my life. That's because I
found a good use for those old
engineering textbooks that I've had.
Semper Fi!