Sampling oscilloscope concepts
Pretrigger data can help you troubleshoot signal problems. For example, to
fi
nd the cause of an unwanted glitch in your test
circuit, trigger on the glitch signal and look at the pretrigger waveform. By analyzing what happens before the glitch, you may
uncover information that helps you
fi
nd the source of the glitch.
Trigger slope and level concepts
The oscilloscope must detect both the slope and level conditions before it can trigger and display a stable waveform.
The minimum trigger conditions needed to display a stable waveform are the signal slope and threshold level. The
slope sets the oscilloscope to
fi
nd the trigger point on the rising or the falling edge of a signal. The level sets where on
that edge the trigger point occurs.
The trigger
Slope
sets the oscilloscope to
fi
nd the trigger event on the rising or the
falling edge of a signal.
The trigger threshold
Level
(or just level) is
the signal amplitude value on a slope that
must occur for the oscilloscope to trigger on
a signal.
A runt trigger needs two thresholds to de
fi
ne
the two levels that a signal must pass through
to be considered a valid (nonrunt) signal.
The arrow at the far right of the screen marks
the threshold level(s) for that signal.
Turning the
Trigger Level
knob changes
the threshold level and momentarily displays
a long horizontal line (or two lines for a
runt trigger) across the waveform to show
the trigger level(s) in relation to the overall
waveform.
Available trigger types
The oscilloscope lets you trigger on several signal conditions:
TBS2000 Series User Manual
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