10
Keysight 346B, 346C, N4001C, and N4002A Installation Note
Procedure
If the ENR of the noise source does not meet specification, the polyiron rod is used to tune the
response of the noise source. For step 1, follow the procedure depending on the model:
1 346B/ N4001A
:
Screw the polyiron rod into the threaded hole of the cartridge approximately half way to the
substrate.
346C/ N4002A
:
Screw the polyiron rod into the threaded hole of the cartridge to between 75% and 90% of the
way in to the substrate.
2
Cut off the excess polyiron using a razor blade or sharp knife.
3
Install the replacement attenuator into the noise source and test the noise source for ENR and
Reflection.
The polyiron will decrease Reflection and ENR at high frequencies (above 12 GHz).
If the ENR is too low at high frequencies, unscrew the polyiron 1 to 2 turns and trim flush. If the
ENR is too high, screw the polyiron further into the cartridge. Take care not to allow the polyiron
to touch the substrate.
NOTE
Be careful not to allow the polyiron to touch the substrate.
NOTE
Be careful when using sharp objects and use the appropriate precautions.
