HP ESA-L1500A, Руководство пользователя и калибровки

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76 Chapter 4
Front-Panel Key Reference
Display
Display
Display
accesses the
Title
menu keys which allow title entry, and the
Preferences
menu keys which allow you to turn the graticule,
annotation, time/date, or inverse video, on or off. Display softkeys also
include
Display Line On Off
,
Threshold On Off
, and
Contrast
.
Display Line On
Off
activates an adjustable horizontal line that is used as a visual reference
line. The line, which can be used for trace arithmetic, has amplitude
values that correspond to its vertical position when compared to the
reference level. The value of the display line appears in the active
function block and on the left side of the display. The display line can be
adjusted using the step keys, knob, or numeric keypad. Pressing any
digit, 0 through 9, on the numeric keypad brings up the selected
terminator menu. To deactivate the display line, press
Display Line On
Off
so that
Off
is underlined. (Also see the
Video
(trigger) key
description in the
Trig
key menu.) Key Access:
Display
Threshold On Off
sets a lower boundary to the active trace. The threshold line “clips”
signals that appear below the line when this function is on. The
boundary is defined in amplitude units that correspond to its vertical
position when compared to the reference level.
The value of the threshold appears in the active-function block and on
the lower- left side of the display. The threshold level does not influence
the trace memory or marker position. The peaks found by the markers
must be at least the peak- excursion value above the threshold level.
The value of the threshold level can be changed using the step keys, the
knob, or the numeric keypad. Pressing any digit, 0 through 9, on the
numeric keypad brings up the selected terminator menu. If a threshold
is active, press
Threshold On Off
until
Off
is underlined to turn the
threshold display off. The threshold value affects peak searching even
when the Threshold function is set to Off. The Threshold function is
also activated by the Pk Threshold function in the
Search
menu. Key
Access:
Display
Title
accesses the following
Title
menu keys which allows you to execute,
change, or clear a title on your display. Key Access:
Display
Change Title
allows you to write a 53-character title across the top of
the display. The marker readout may interfere with the
last 26 characters. The markers can be turned off by
pressing
Marker
,
Marker All Off
. Pressing
Change Title
accesses the softkey menus that contain the available
characters and symbols.