In this video we're going to discuss how update rate can be used to debug infrequent events
using the Keysight 4000 X-Series Oscilloscope.
The 4000-X utilizes Keysight's patented MegaZoom IV ASIC, which provides the industry's fastest
uncompromised update rate, along with many powerful debug features never before seen in an oscilloscope.
Let's begin.
One of the benefits of a very fast update rate like the 4000-X's
is it greatly increases your likelihood of capturing infrequent events.
Infrequent events are so challenging to debug because by definition they are rare.
As you can see on the screen, we have a very intermittent glitch happening on our test signal.
This glitch happens approximately once every million
clock cycles with the one million waveform per second update rate of the 4000-X you can see it on average once a second.
With slower update rates you might have to wait for tens
of seconds, to minutes, to even hours to see this glitch.
Not an easy thing to debug when your scope is hiding the real issue.
In fact, the 4000-X has a built in demo that can show
you how the 4000-X's update rate compares to slower update rates.
Here you can see an update rate of 50,000 waveforms per second, twenty times slower.
And here you can see an update rate of 3,000 waveforms per second.
Unless we are really lucky, we'll be waiting for minutes to see this glitch.
Now let's go back to one million waveforms per second.
Now that we know the glitch is there we can isolate it.
Based on the shape of the signal a pulse width trigger would make sense,
but first we have to figure out what the pulse width is.
By turning on infinite persistence we can maintain a record of all the waveforms that have been displayed on the screen.
Infinite persistence and fast update rate go together beautifully.
Infinite persistence is only helpful if the update rate is fast enough to show those infrequent events.
In this case we're capturing multiple glitches over several seconds.
We can then use cursors to identify the width of the glitch.
As you can see, the glitch is approximately thirty ns in width.
Now that we know the width of the glitch let's isolate it using the pulse width trigger.
We'll need to set up the trigger to look for positive pulses
that are less than thirty ns wide.
You'll notice that the scope doesn't appear to have a stable trigger.
This is because the glitch is so infrequent that the scope
is trying to auto-trigger in between the glitches.
By turning the scope trigger mode to normal-
versus auto- the scope will only trigger when it sees the pulse width less than thirty ns.
Finally, let's insert an annotation that explains what we just triggered on for documentation purposes.
One interesting thing to note. With the 4000-X's InfiniiScan Zone Trigger capability,
we could have easily triggered on this infrequent glitch just by drawing a box.
That is one of the strengths of the 4000-X's Infiniiscan Zone Trigger.
If you can see it on the screen, you can trigger on it.
As you can see, a fast update rate allows you to find infrequent
events that other scopes may miss. You can then use infinite persistence combined with
the powerful triggering on the 4000-X to isolate those infrequent and rare events.
To learn more about Keysight's new InfiniiVision X-Series oscilloscopes, contact your local Keysight
distributor and ask them for a demonstration. Thank you.