Keysight N8973B User Manual

Keysight NFA Series Noise Figure Analyzers Service Guide 139
RF Section Troubleshooting (N8973B, 74B, 75B Analyzers)
RF Section Description
A14 L.O. Synthesizer Assembly
The L.O. Synthesizer Assembly provides the 1st L.O. power that is required for
the A13 RF Front End Assembly. The 1st L.O. has a frequency range from 3.80
to 8.70 GHz. Harmonics of the 1st L.O. are used to down convert RF input
signals up to 26.5 GHz. Table 4-1 provides some examples of how the L.O. is
multiplied for the given center frequency of the analyzer and which high band
mixer is being used on the A13 RF Front End assembly. The output power is
+13 to +18 dBm. In order to maximize the conversion efficiency, sufficient L.O.
power must be supplied to the mixer in the A13 RF Front End Assembly from
this assembly.
Table 4-1 X-Series Signal Analyzers
Analyzer
Center Frequency
a
1st L.O.
@ A14J740
Desired 1st L.O. Harmonic
@ Mixer 2 or 3
5 GHz 5.3225 GHz
5.3225 GHz
b
10 GHz 5.16125 GHz
10.3225 GHz
b
13.5 GHz 6.91125 GHz
13.8225 GHz
b
14.5 GHz 7.41125 GHz
14.8225 GHz
c
22 GHz 5.5806250 GHz
22.3225 GHz
c
a. Set span to Zero Span to measure 1st L.O.
b. A13 Mixer 2 (refer to Chapter 12, “Block Diagrams.”)
c. A13 Mixer 3 (refer to Chapter 12, “Block Diagrams.”)

Keysight N8973B Specifications

General

Brand	Keysight
Model	N8973B
Category	Measuring Instruments
Language	English