User manual

27
UNI-T
®
UT4000 User Manual
Setting up the Trigger System
Triggering decides when the oscilloscope collects data and display waveforms. Once the
trigger is correctly set up, it offers stable display of the waveform being observed. When
beginning to acquire data, the digital storage oscilloscope first collects data required for
pre-trigger. When the trigger condition arises, it will continue to acquire the remaining
data.
The trigger control zone on the operation panel of your digital storage oscilloscope
comprises a trigger level adjustment knob, a trigger menu button [MENU], [50%] for
setting up the trigger level at the vertical centre point of the signal, and a compulsory
trigger button [FORCE].
Trigger level : Trigger level sets the trigger point of the signal being tested.
[50%] : Setting the trigger level at the vertical centre point of the trigger signal
amplitude.
[FORCE] : To generate a compulsory trigger signal. Mainly used in the trigger mode and
“Normal” and “Single” modes.
[MENU] : Button for the trigger setup menu.
Trigger Control
Trigger modes : Edge, pulse, video, slew rate and logic analyzer (LA).
Edge trigger : Trigger is set to occur when the signal is at the rising or falling edge. You
can set the trigger level to change the trigger point’s vertical position on the trigger edge,
i.e. the intersection point of the trigger level line and the signal edge on the screen.
Pulse trigger : When the pulse width of the trigger signal reaches a preset trigger
condition, trigger occurs.
Video trigger : Carry out field or line trigger to standard video signals.
Slew rate trigger : Trigger condition is the signal rising or falling rate.
LA trigger : Trigger condition is the pattern or duration input by the logic analyzer. To
use this trigger mode you must have a LA probe installed and turned on.
Below are notes for various trigger menus.
Edge Trigger : For edge trigger menu setups please see Table 2-7.
Table 2-7
Function Menu Setup Explanatory Note
Type Edge
Signal source
selection
CH1
CH2
EXT
EXT/5
AC
CH1 & CH2
Set CH1 as the signal source trigger signal.
Set CH2 as the signal source trigger signal.
Set the external trigger input channel as the signal
source trigger signal.
Divide the external trigger model by 5.
Set grid trigger.
CH1 and CH2 trigger their respective signals
alternately.