Keysight Technologies FieldFox N9913A Service Manual page 61

Theory of Operation
Measurement Group
NA RF Section
An LO synthesizer produces a single LO signal from the 90 MHz time base
located on the A5 System board. The LO output is delivered to the NA mixers of
both ports. The LO frequency is always above the measured frequency. The IF
is 390 kHz.
The LO output is switched between the NA mixers and the SA first converter
depending on the function being used. At any instant in time, either the NA
receivers or the SA receiver may be active, but not both at the same time.
The 90 MHz time base is also used to generate a source signal in the source
synthesizer that covers the frequency range of 10 MHz to 26.5 GHz. The source
signal is generally rich in harmonic content. This is acceptable because the
signal is used with tuned receivers.
The frequency bands for the NA circuitry on the RF board are listed below:
Table 5-1
Keysight FieldFox Handheld Analyzers Service Guide
Frequency Bands - NA RF Section 
N991xA, N992xA, N993xA
Band Instrument
Start
P1 0.030
2 2.035
3 2.425
4 4.500
5 4.850
6 9.350
7 9.700
8 19.100
9 19.500
10 38.800
11 78.000
12 156.250
13 312.500
14 625.000
15 1250.000
16 2500.000
17 5000.000
18 10000.000
Stop
2.035
2.425
4.500
4.850
9.350
9.700
19.100
19.500
38.800
78.000
156.250
312.500
625.000
1250.000
2500.000
5000.000
10000.000
15000.000
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