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4000 X-Series Oscilloscopes Advanced Training Guide
4
Serial Bus Decoding & Triggering, Search & Navigation, and Segmented Acquisition Labs
Lab #22: Decoding, Triggering, and Searching on Universal Serial Bus
(USB) Signals
In this lab you will learn how to set up the scope to decode and trigger on USB
traffic. In addition, you will learn how to use the scope's automatic Search &
Navigation capability, as well as use Segmented Memory acquisition to capture
multiple and consecutive occurrences of a particular operation. This lab does not
provide a tutorial on the USB protocol. Also, the USB signal provided is not a
complex representation of true USB traffic; our training signal will consist of four
IN transactions, using low-speed (USB 1.1) for simplicity. To complete this lab,
your scope must be licensed with the USB 2.0 Full/Low Speed serial decode and
triggering option (Option USF). You can verify the installed options on your
oscilloscope at
[Help] > About Oscilloscope
.
1
Connect the channel-1 probe to the Demo 1 terminal and ground.
2
Connect the channel-2 probe to the Demo 2 terminal and ground.
3
Press
[Default Setup]
on the scope's front panel.
4
Press
[Help]
; then tap the
Training Signals
softkey.
5
Select and enable the
USB
signal.
6
Set channel-1 to
1.00 V/div
.
7
Tap the channel 2 button to enable channel 2 output.
8
Set channel-2 to
1.00 V/div
.
9
Set channel-2 offset to
3.50 V
.
10
Push the trigger level knob to set the trigger level to approximately
50%
.
11
Set the scope's timebase to
20.0 µs/div
.
You should see on your scope's display what appears to be an un-triggered display
of two digital signals similar to
. Your scope is actually triggering on
random rising edges of channel-1, which is the scope's default trigger condition.
But these signals are too complex to establish a unique trigger point using simple
edge triggering. Let's first set up the scope to intelligently decode this data stream
based on the USB protocol, and then we will establish a more unique trigger point
using USB triggering.
Содержание 4000 X-Series
Страница 12: ...12 4000 X Series Oscilloscopes Advanced Training Guide 1 Getting Started...
Страница 156: ...156 4000 X Series Oscilloscopes Advanced Training Guide A Oscilloscope Block Diagram and Theory of Operation...
Страница 166: ...166 4000 X Series Oscilloscopes Advanced Training Guide B Oscilloscope Bandwidth Tutorial...
Страница 168: ...168 4000 X Series Oscilloscopes Advanced Training Guide C Related Keysight Literature...