Teledyne LeCroy HDO 4000 Operators Manual - Manual (Page 49)

HDO4000 High Definition Oscilloscope
Trigger Settings
To access the Trigger setup dialogs, choose Trigger > Trigger Setup from the menu bar, or press the Front
Panel Trigger Setup button.
The dialogs you see and the options on them will vary depending on your trigger type selection. The main
Trigger dialog contains settings that are required for most trigger types.
The trigger setup is summarized in a preview window at the far right of the Trigger dialog.
Type - see Trigger Types for details. This selection drives the remainder of the trigger setup. The default
selection is Edge.
Source - the channel signal upon which to base the trigger. If a trigger is designed to work with multiple
inputs, like a Pattern trigger, you do not have to choose a single source, but will be given controls for
setting the conditions on each source.
Coupling - the type of signal coupling at the input. Choices are:
l
DC - All the signal’s frequency components are coupled to the trigger circuit for high frequency
bursts or where the use of AC coupling would shift the effective trigger level.
l
AC - The signal is capacitively coupled. DC levels are rejected, and frequencies below 50 Hz are
attenuated.
l
LFREJ - The signal is coupled through a capacitive high-pass filter network, DC is rejected and sig-
nal frequencies below 50 kHz are attenuated. For stable triggering on medium to high frequency sig-
nals.
l
HFREJ - Signals are DC coupled to the trigger circuit, and a low-pass filter network attenuates
frequencies above 50 kHz (used for triggering on low frequencies).
Level - the source Voltage level or levels that mark the threshold for the trigger to fire. Trigger levels
specified in Volts normally remain unchanged when the vertical gain or offset is modified.
Find Level - where available, this button sets the Level to the signal mean.
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