Keysight Technologies 86120B, User Manual

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62
Using the Multi-Wavelength Meter
Measuring Total Power Greater than 10 dBm
Measuring Total Power Greater than 10 dBm
The maximum total power that can be measured by the Agilent 86120B is 10 dBm.
However, with the addition of an external attenuator, more power can be applied.
This may be necessary at the transmit end of a wavelength-division-multiplexed
system where large signal levels are present. By entering an amplitude offset equal
to the amount of attenuation at the instrument’s input, accurate amplitude measure-
ments are shown on the display. Additional amplification can also be accounted for.
To measure total power exceeding 10 dBm
C A U T I O N
The maximum total input power that can be applied to the Agilent 86120B
before damage occurs is 18 dBm. The maximum total input power that can be
measured is 10 dBm.
1 Connect an optical attenuator between the front-panel OPTICAL INPUT connector
and the fiber-optic cable.
The attenuator must reduce the total input power to the Agilent 86120B so that it is
below +10 dBm.
2 Press Setup , MORE , CAL , and then PWR OFS .
Notice that the
PWR OFS
annotation appears on the screen to indicate an offset is
applied.
3 Use the softkey to select the digit that requires editing.
4 Use the and softkeys to change the value.
Power offset values are added to the display power readings. For example, if you
placed a 10 dB attenuator on the front-panel connector, enter a power offset value of
+10 dB. Negative values can also be entered if you connect an amplifier instead of
an attenuator.