Keysight CXG, EXG, and MXG X-Series Signal Generators Service Guide 243
Baseband Generators
A2 Vector BBG Assembly Overview
Digital Section
The digital section receives a 100 MHz clock signal from the A3 RF assembly at
P500. This reference clock is multiplied and divided within the assembly to
provide different clock frequencies for the different circuits on the assembly.
There are several adjustments related to the digital section found in the
performance verification and adjustment software for these instruments, which
will be covered later in this chapter.
The digital section has an I/Q mux that gives it the ability to select what I/Q
data is sent to the I/Q modulator, whether it is the I/Q pairs generated by the
internal arbitrary waveform generator or what is applied to the external I/Q
inputs. It also routes the internally generated I and Q signals to the baseband I
and Q output connectors.
The digital section of the A2 Vector BBG assembly also contains the volatile
BBG waveform memory that is installed in the two 240 pin DIMM slots on the
assembly. The amount of memory that ships with an N5166B or N5172B
instrument is 2 GB, while an N5182B instrument ship with 4 GB. The amount of
memory installed on the assembly can be seen on the Installed Board Info
screen, as can be seen in Figure 12-1. In this example the amount of memory
shown is 2GB + 2GB for a total of 4 GBs. There are two values shown since
there is memory in both slots. However, it should be noted that replacement A2
Vector BBG assemblies come with 4 GBs of memory installed in them, so it is
possible to have more than 2 GBs of memory in N5166B or N5172B
instruments. However, the options installed will limit the amount of memory
that is available to the user.
Self Test
There is an extensive number of Self Tests for the A2 Vector BBG assembly. All
the 700, 800, and 900 series Self Tests are for the A2 Vector BBG assembly.
See Chapter 4, “Self Test,” for complete information on these tests.
Calibration Data
Calibration data for the assembly is stored on the A2 Vector BBG assembly.
This is data that was either written to the assembly when the instrument was
produced at the factory or by an adjustment in the performance verification
and adjustment software. Also, replacement A2 Vector BBG assemblies come
from the factory with calibration data stored in them. See “Calibration Data” in
Chapter 3, “Instrument Information and Calibration Data,” for complete
information on the instrument calibration data.
To Next Page
Loading...
Need help?
General
