Teledyne LeCroy WaveRunner XI SERIES Operator’s Manual - Manual (Page 59)

O
PERATOR
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ANUAL
Determining Trigger Level, Slope, Source, and Coupling
1. Level defines the source voltage at which the trigger circuit will generate an event: a change in the input
signal that satisfies the trigger conditions. The selected trigger level is associated with the chosen trigger
source.
Trigger level is specified in volts and normally remains unchanged when you change the vertical gain or
offset.
The amplitude and range of the trigger level are limited as follows:
o ±5 screen divisions with a channel as the trigger source
o ±400 mV with EXT as the trigger source
o ±4 V with EXT/10 as the trigger source
o ±40 mV with EXT*10 as the trigger source
o None with LINE as the trigger source (zero crossing is used).
2. Coupling refers to the type of signal coupling at the input of the trigger circuit. Because of the instrument's
very high bandwidth, there is only one choice of trigger coupling: DC 50 ohms. However, as a visual check of
where ground is, you may switch the channel to ground coupling at any time while testing.
With DC coupling, all of the signal's frequency components are coupled to the trigger circuit for high-
frequency bursts.
3. Slope determines the direction of the trigger voltage transition used for generating a particular trigger event.
You can choose a positive, negative, or windowed slope. Like coupling, the selected slope is associated with
the chosen trigger source.
Edge trigger works on the selected edge at the chosen level. The slope (positive or negative) is specified in the Trigger label
permanently displayed below-right of the grid.
Trigger Source
The Trigger Source source may be one of the following:
• The acquisition channel signal (CH 1, CH 2, CH 3 or CH 4) conditioned for the overall voltage gain, coupling,
and bandwidth.
• The line voltage that powers the oscilloscope (LINE). This can be used to provide a stable display of signals
synchronous with the power line. Coupling and level are not relevant for this selection.
• The signal applied to the EXT BNC connector (EXT). This can be used to trigger the oscilloscope within a
range of ±400 mV on EXT, ±4 V with EXT/10 as the trigger source.
• A logic pattern.
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