Measuring Total Power Greater Than 10 Dbm - Agilent Technologies 86121A User Manual

3-24 Measuring Total Power Greater than 10 dBm

Measuring Total Power Greater than 10 dBm
C A U T I O N
The maximum total power that can be measured by the
Agilent 86121 WDM Channel Analyzer is 10 dBm. How-
ever, 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 sys-
tem where large signal levels are present. By entering
an amplitude offset equal to the amount of attenuation
at the input of the instrument, accurate amplitude mea-
surements are shown on the display. Additional amplifi-
cation can also be accounted for.
The maximum total input power that can be applied to
the Agilent 86121 WDM Channel Analyzer before
damage occurs is 18 dBm. The maximum total input
power that can be measured is 10 dBm.
To measure total power exceeding 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
86121A 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
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.
softkeys to change the value.