Agilent Technologies E4406A, Руководство пользователя

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90 Chapter 4
Making Measurements
Preparing for Measurements
by using the
Normal
,
Delta
, or
Function
keys. If a marker has
previously been turned on and assigned to a specific trace it will
become active on that trace when the
Select
key is pressed.
• Delta - Places two markers on the selected trace or, if a marker is
already active, places a second marker at the position of the active
marker. You can activate up to two sets of delta markers. Annotation
in the active function area and in the upper-right corner of the
display show differences between the two markers in the units of the
window which contains that marker.
•
Off
- Turns off the selected marker (as set by the
Select
key).
• Marker All Off - Turns off all markers.
• Shape - Allows you to select markers in the shapes of diamonds,
crosses, squares, and lines. The line markers run vertically, from the
bottom to the top of the display, while the diamond, square, and
cross shapes simply allow you to distinguish different points on the
trace by using different shapes. You may use up to four different
shaped markers at a given time, although only one may be active.
Marker Functions
The marker
Function
menu key enables you to use two marker
functions:
Band Power
and
Noise
. These functions do not apply to all
measurements; if you attempt to press a function key for a function
that is not applicable to that measurement a message will appear
telling you that the function is not supported under the current
measurement. These functions are described below. Press
Marker
,
Function
to access the following keys.
• Band Power - Allows you to place two markers to either side of a
band so you can measure the power within that band. You can use
the RPG knob to move the band markers; the numerical power
reading will be visible in the upper right corner of the display. This
feature is particularly useful for measuring channel power.
• Noise - Normalizes the equivalent amplitude of the measured noise
to a 1 Hz bandwidth, which is centered around the displayed marker.
This is done by sampling and displaying the average of 32 data
points.
Search Marker
The front panel
Search
key performs a peak search when pressed. A
marker will automatically be activated at the highest peak.