HP 54540 Series - Page 89

Trigger
Edge Trigger Mode
Source Softkey
The source softkey selects the trigger source. The options are any channel
input, auxiliary input (on the rear panel), external trigger input (on the
2-channel models only), or line trigger. The current selection is highlighted
in inverse video. When line is selected as the source, the oscilloscope uses
the power line as the trigger source, and the remaining menu choices are
removed. Also, holdoff is not available with line trigger or auxiliary trigger.
Level Softkey
The level softkey has two modes, adjust and center.
Adjust Adjust allows the flexibility of setting exact triggering points and
specifies levels used in the other triggering modes. The trigger level
range depends on the source.
e Channel inputs — +12 divisions from the center of the screen.
e Auxiliary input — +5 V.
e External trigger — There are three ranges:+1 V, +5 V, and + 25 V.
Center For the channel inputs, center sets the trigger level to the same
value as the channel offset for the selected source, which places the
trigger level at the center of the screen. For the auxiliary and external
inputs, center sets the trigger level to 0 V.
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