Understanding Option 012 (Lo In/Out For Phase Coherency); With Multiple Baseband Generator Synchronization; Configuring The Option 012 (Lo In/Out For Phase Coherency) With Mimo - Keysight Technologies N5166B CXG User Manual

Understanding Option 012 (LO In/Out for Phase Coherency) with Multiple Baseband Generator

Understanding Option 012 (LO In/Out for Phase Coherency)

with Multiple Baseband Generator Synchronization

This section assumes that the previous section on Multiple Baseband
Generator Synchronization has been read and understood. If not, refer to
"Multiple Baseband Generator Synchronization" on page 285
continuing.
The MXG/EXG with Option 012, enables 2x2, 3x3, or 4x4 MIMO configurations to share a common
external LO signal to create a phase coherent system (refer also, to
Synchronization" on page
RF phase coherency may not be needed for general STC/MIMO receiver testing, since a MIMO
receiver perceives any phase differences between the sources as part of the channel conditions and
correct for them. But, RF phase coherency might be desirable for certain applications such as R&D
on beamforming systems.

Configuring the Option 012 (LO In/Out for Phase Coherency) with MIMO

The Keysight BNC cable, part number 10502A, is the recommended cable for the standard multi–
BBG synchronization setup, and is recommended for Option 012 too (see also
page 288). Additionally, for the 2x2, 3x3, and 4x4 MIMO connections from the LO IN and LO OUT to
the splitter, additional cables are required (refer to
9-31 on page 294).
Keysight recommends the LO Output be covered when not in use.
When the LO In/Out jumper cable is removed and the instrument is in Dual
ARB mode, the instrument is unleveled and the instrument displays an
Unlevel error message.
All test equipment requires a 12 hour warm–up period to ensure accurate
performance.
The phase coherent configuration requires the following:
— The recommended LO input drive level should be in the 0 to 6 dBm range.
The 0 to 6 dBm LO input drive level ensures the instruments will operate
over the full frequency and over the full 0 to 55 ambient temperature
range
a. LO input power requirements vary with temperature; power <0 dBm may work at 20–30 degree
ambient temperature conditions. Refer to the Data Sheet.
— The I/Q calibration and the self–test must be performed with the LO In/Out jumper cable in
place. Where the I/Q calibration cannot be run, the baseband offset can be manually adjusted
to minimize the I/Q offsets.
Keysight CXG, EXG, and MXG X-Series Signal Generators User's Guide
285).
a
.
Basic Digital Operation (Option 653/655/656/657)
"Multiple Baseband Generator
Table , Figure 9-30 on page
Synchronization
before
Figure 9-29 on
293, and Figure
291