Measurement Group; A4 Rf Board - Keysight N9912A Service Manual

RF Analyzer
N9912A

Measurement Group

The measurement group produces a stable output signal by phase locking a synthesized voltage-controlled
oscillator (VCO).
The measurement group consists of the:
•

A4 RF Board

• A5 System Board
• A6 SOM Board
• Main Battery
A simplified RF block diagram is provided in
A simplified system block diagram is provided in
A4 RF Board
The basic function of the A4 RF board is to provide a signal source and receivers for the analyzer functions.
There are three sections to the A4 RF board:
• the Common RF section,
• the CAT/NA RF section, and the
• SA RF section.
Common RF Section
This section is common to both NA and SA functions. In this common section, an LO synthesizer produces a
single LO signal from the 30 MHz time base located on the A5 system board. 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 LO frequency bands are listed below:
1 100 kHz to 1.6 MHz
2 1.6 MHz to 25 MHz
3 25 MHz to 0.2 GHz
4 0.2 GHz to 0.8 GHz
5 0.8 GHz to 1.6 GHz
6 1.6 GHz to 3.2 GHz
7 3.2 GHz to 3.4 GHz
8 3.4 GHz to 4.15 GHz
9 4.15 GHz to 5.1 GHz
10 5.1 GHz to 6.2 GHz
Service Guide N9912-90003
Figure 5-2.
Figure 5-3.
Theory of Operation
Measurement Group
5-7