Oscilloscope Familiarization Labs
2
4000 X-Series Oscilloscopes Advanced Training Guide
21
Lab #2: Using Zoom Display to Perform Gated Measurements
When performing automatic parametric measurements, such as positive pulse
width measurements, on an exactly repetitive input signal, such as a simple sine
wave or square wave, it really doesn’t matter which particular pulse the scope
chooses to make the measurement on; each pulse is the same. But what if the
input signal you are probing is more complex; where each pulse has unique
parametric characteristics? In this case, you would first need to set up the scope to
trigger at a unique point in time on the complex signal, and then you would need
to set up the scope’s measurements in such a way that the scope would be more
selective as to which pulse it chooses to perform measurements on. In this lab you
will learn how to perform selective, or “gated”, measurements on specific pulses
using the scope’s Zoom display mode.
1
Connect the channel-1 probe to the Demo 1 terminal and ground.
2
Press the
[Default Setup]
key on the scope’s front panel.
3
Press
[Help]
; then press the
Training Signals
softkey.
4
Select the
Digital Burst with Infrequent Glitch
signal; then press the
Output
softkey
to turn it on.
5
Set channel-1’s V/div setting to
1.0 V/div.
6
Set channel-1’s position/offset setting to approximately
2.0 V
in order to center
the waveform on-screen.
7
Push the trigger level knob in order to automatically set the trigger level at
approximately
50%
(~1.7 V).
8
Set the scope’s timebase to
1.000 µs/div
.
9
Press the
[Mode/Coupling]
front panel key near the trigger level knob.
10
Press the
Holdoff
softkey; set the trigger holdoff value to
4.000 µs
.
With the scope’s trigger holdoff feature turned on and set to 4.0 µs, the scope now
triggers on the 1st rising edge of the burst, disarms triggering for 4.0 µs, and then
re-arms triggering after the last pulse in the burst so that the scope will again
trigger on the 1st pulse during the next repetition of the burst. We have now
established a stable and unique trigger point on this complex digital signal using
Trigger Holdoff. You can learn more about Trigger Holdoff during
