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3-54
Using the Optical Spectrum Analyzer
The System Menus
4
Use the arrow keys or the numeric entry pad to set the wavelength span
manually or automatically. Refer to “To Fill In a Setup Panel” on page 3-65 for
information on changing and selecting items in the setup panel.
Setup panel
selections
Span
This function selects the wavelength span for viewing the signal located by the
auto measure function. If Auto is specified, the span is set wide enough to dis-
play most of the signal. If a particular span is desired, deselect Auto and put
the desired span in the nm dialog box. The default selection for Span is Auto.
Scale/Div
The dB/div selection sets the vertical scale to be used after performing the
auto measure function. If Auto is specified, the measurement function sets the
vertical scale to a value based on the dynamic range of the signal. If a particu-
lar vertical scale is desired, deselect Auto and put the desired dB/div in the dB
dialog box. The default selection for dB/div is Auto.
AutoMeas at Marker
Selecting the
ON
state for AutoMeas at Marker causes the auto measure func-
tion to perform its operation at the wavelength of the active marker. This
allows you to measure a signal other than the largest one found in a full span
sweep. The default selection for Automeasure at Marker is
OFF
.
Optimize Sensitivity
Selecting the
ON
state for Optimize Sensitivity causes the auto measure func-
tion to set the sensitivity so the resulting measurement has a minimal amount
of noise. It does this by finding the minimum in the measurement trace and
comparing this value to the known sensitivity of the instrument at that wave-
length. Sensitivity is then reduced until the signal is close to this minimum
sensitivity or the sweep time becomes too long. The Optimize Sensitivity func-
tion is useful when viewing high dynamic range signals. The drawback to turn-
ing this function
ON
is that it generally requires a longer sweep time to get
better sensitivity. The default selection for Optimize Sensitivity: is
OFF
.
Note
If the span is set too narrow, the auto measure operation may not complete successfully.
If this happens a warning message is displayed.
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