User manual

54
UNI-T
®
UT4000 User Manual
Illustration 3 : Acquiring single signals
The advantage and special feature of your digital storage oscilloscopes lie in its ability to
acquire non cyclical signals like pulse and glitch. To acquire a single signal, you must
have transcendental knowledge of that signal to set the trigger level and trigger edge. For
example, if the pulse is a logical signal of TTL level, the trigger level should be set at
about 2V and the trigger edge should be set to rising edge trigger. If you are not certain
about the signal, you can observe it by automatic or normal trigger to determine the
trigger level and trigger edge.
Steps :
1. As in the previous illustration, set the attenuation factor of the probe and CH1.
2. Carry out trigger setup.
c Press [MENU] in the trigger control zone to display the trigger setup menu.
d In this menu, use [F1]~[F5] menus to set the trigger type to edge, set trigger source
to CH1, set trigger coupling to AC, set trigger type to single and set edge type to
rising.
e Adjust horizontal time base and vertical range to an appropriate range.
f Turn the TRIGGER LEVEL
control knob to get the desired level.
g Press [RUN/STOP] and wait for a signal that meets the trigger condition. If any
signal reaches the set trigger level, the system will sample once and display it on the
screen. By using this function you can easily acquire any occasional event. For
example, when a sudden glitch of relatively big amplitude is acquired : set the
trigger level to just higher than the normal signal level. Press [RUN/STOP] and
begin waiting. When a glitch occurs, the machine will automatically trigger and
record the waveform immediately before and after triggering. By turning the
horizontal POSITION
knob in the horizontal control zone on the front panel, you
can change the trigger position horizontally to achieve negative delay trigger of
various lengths for easy observation of waveform occurring before the glitch.
Figure 3-3 Single signal