Rohde & Schwarz R&S SMW200A - Generating Phase-Coherent Signals; Multi-Instrument Setups; Synchronizing Instruments

Multi-Instrument Setups
R&S
®
SMW200A
639User Manual 1175.6632.02 ─ 30
10 Multi-Instrument Setups
R&S SMW is rarely used as a standalone instrument. Usually, the instrument is con-
nected to a device under test (DUT) or other measurement equipment.
Test setups have different requirements, for example:
●
Test setups comprising two or more instruments often require a common reference
frequency.
●
Generation of beamforming signals requires phase coherent signals.
●
Some test setups also require control of the signal generation start and an exact
generation start time, for example determined by a defined trigger event.
●
In other cases, you would need time-aligned simultaneous signals within the instru-
ment or possibly also between multiple instruments.
●
MIMO test scenarios can require more than two RF signals, generated by process-
ing the I/Q output signals of the R&S SMW by external instruments like the
R&S SGT or the R&S SGS.
●
The generation of WLAN 802.11ad signals at 58.3 GHz requires an up-converter
as the R&S SZU.
●
Radar echo generation requires a connected R&S FSW.
●
etc.
R&S SMW provides several settings that help fulfilling these requirements. This section
explains main principles and gives an overview of the related settings and step-by-step
instructions.
● Synchronizing Instruments....................................................................................639
● Generating Phase-Coherent Signals.................................................................... 639
● Generating Time-Aligned Baseband Signals........................................................ 640
● Generating Phase-Coherent Synchronous and Aligned Signals.......................... 650
● Control and Operation of External Instruments.....................................................667
10.1 Synchronizing Instruments
For information on the possible scenarios concerning the distribution of reference fre-
quency, test setups and the related settings:
See Chapter 8.5, "Reference Oscillator", on page 473.
10.2 Generating Phase-Coherent Signals
The R&S SMW provides a build-in function that allows a distribution of the local oscilla-
tor signal in a way that multiple RF signals can be derived from the same LO signal.
LO coupling is mandatory for minimizing the phase fluctuations between these RF sig-
nals, as it is, for example, required for the generation of beamformed signals.
Generating Phase-Coherent Signals