Keysight Technologies 86120B, User Manual

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Measurements Applications
Measuring Laser Drift
To measure drift
1 Press the front-panel Preset key.
2 Press Peak WL, List by WL, or List by Power to select the display style for observing
drift.
3 Press Appl’s and then DRIFT .
Pressing DRIFT sets the current laser-line values as the reference from which to com-
pare all drift.
4 Press MAX-MIN for the desired type of drift measurement as described in the
following paragraphs:
Display shows the current values of laser lines relative to the
wavelength and power values measured when the test was
begun or the
RESET softkey was pressed.
Display shows absolute maximum values since the drift
measurement was started. This measurement gives the
longest
wavelength and greatest power measured. The laser line of
interest may have since drifted to a lesser value. Note that the
maximum wavelength and maximum power may not have
occurred simultaneously.
Display shows absolute minimum values since the drift
measurement was started. This measurement gives the
shortest
If measurement updating stops or the values become blanked
If, in the middle of a measurement, the number of laser lines present changes,
the measurement stops until the original number of lines returns. You’ll notice
that a
CLEAR softkey appears and one of the following message is displayed:
E46 NUM LINES < NUM REFS
E47 NUM LINES > NUM REFS
To view the data measured before the conditions changed, press CLEAR and
then MAX-MIN. Notice that the measurement acquisition is changed from con-
tinuous to single.
To restart testing, press CLEAR, the CONT key, and then RESET to use the
new number of lines as the reference. Pressing CONT restarts continuous mea-
surement acquisition. Or, you can restore the original number of lines on the
input so that the drift measurement can continue.