Keysight Technologies N5261A User's And Service Manual page 68

Service Information
Coupler (0955-0148)
Directional couplers with 10 dB coupling factor are used for ALC feedback for
RF and LO Output leveling.
Slope Attenuator Cable Assy (N5262-20033)
A slope pad is installed on the leveling coupler of the RF Out path to
compensate for the RF switch loss at higher frequencies.
Power Divider (N5262-80003)
A four-way power divider provides each Port LO Output from the LO amplifier
with approximately 7.2 dB attenuation for each LO Out. Two 50 ohm
terminators are installed on the unused N5261A divider paths. If a system is
configured with a unused port (a 1-Port reflection system for example) the front
panel LO Output ports are to be terminated with a 50 ohm load (1810-0118).
This keeps the power divider balanced and prevents an "open" reflective signal
from entering the power divider and mixing with the RF signal.
RF Switch (5087-7733)
A solid-state switch with internal 50 ohm termination is used for switching the
RF Output path for Ports 1 and 2, or Ports 3 and 4. These switches are
controlled by the test set controller and interface boards.
Keysight N5261/62A User's & Service Guide
62