Agilent Technologies FieldFox MW N9913A, Service Manual, Page: 60 / 156

5-10 N9927-90003
Theory of Operation FieldFox Analyzer
Measurement Group
The RF Out attenuator between the source and the reflectometer has three settings: nominal values of
0 dB, 35 dB or user input value. The setting is determined by the High, Low or Manual power setting on
the user interface. And beginning from firmware A.06.18, the default output power level is -15 dBm.
The reflectometer performs three functions:
• It passes the source output signal to either PORT 1 or PORT 2.
• It samples the source output to either PORT 1 or PORT 2.
• It samples the incoming signal at either PORT 1 or PORT 2.
The sampled signals are mixed with the LO signal to produce three 390 kHz IF signals, NA-A, NA-B
and NA-R.
The reflectometer dissipates up to 1.5 watts when active.
Each port (PORT 1 and PORT 2) has a DC isolation capacitor.