Agilent Technologies 86140B Series, Руководство пользователя

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3-12
Function Reference
Auto Meas
broadband or narrowband light source. If there is insufficient signal power, the
automatic measurement will not be performed, and a warning message will be
reported. This automatic measurement routine is normally the best way to
adjust sensitivity while maintaining the fastest sweep rates.
The auto measure function uses trace A to perform the measurement. Since
the auto measure function can alter the instrument state, we recommend that
this operation be performed before a measurement sequence is started.
Auto Measure Setup panel allows you to modify the auto measure span and
the vertical scale, tune to the wavelength indicated by the marker, and opti-
mize the sensitivity.
Span 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 display
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.
N o t e If the span is set too narrow, the auto measure operation may not complete
successfully. If this happens a warning message is displayed.
Scale/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 turns the auto measure marker on or off. Selecting the
on state for auto measure at marker causes the auto measure function to per-
form 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 auto measure at marker is off.
Optimize Sensitivity , when turned on, causes the auto measure function 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 com-
paring 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
.