Tektronix TDS 684A, TDS 744A, TDS 784A To set MAIN LEVEL To Set to 50%, To Force a Trigger

Triggering on Waveforms
3–54 TDS 684A, TDS 744A, & TDS 784A User Manual
Trigger Status Lights
Figure 3–33: TRIGGER Controls and Status Lights
To manually change the trigger level when edge triggering (or certain threshold
levels when logic or pulse triggering), turn the MAIN LEVEL knob. It adjusts
the trigger level (or threshold level) instantaneously no matter what menu, if any,
is displayed.
To quickly obtain an edge trigger or a glitch or width pulse trigger, press SET
LEVEL TO 50%. The oscilloscope sets the trigger level to the halfway point
between the peaks of the trigger signal. Set Level to 50% has no effect when
trigger type is logic or video.
You can also set the level to 50% in the Trigger menu under the main menu item
Level if edge trigger or glitch or width pulse trigger is selected.
Note that the MAIN LEVEL knob and menu items apply only to the main trigger
level. To modify the delayed trigger level, use the Level item in the Delayed
Trigger menu.
To force the oscilloscope to immediately start acquiring a waveform record even
without a trigger event, press the FORCE TRIG front panel button.
Forcing a trigger is useful when in normal trigger mode and the input signal is
not supplying a valid trigger. By pressing FORCE TRIG, you can quickly
confirm that there is a signal present for the oscilloscope to acquire. Once that is
established, you can determine how to trigger on it (press SET LEVEL TO
50%, check trigger source setting, and so on).
The oscilloscope recognizes and acts upon FORCE TRIG even when you press it
before the end of pretrigger holdoff. However, the button has no effect if the
acquisition system is stopped.
To set MAIN LEVEL
To Set to 50%
To Force a Trigger