Rohde & Schwarz SMM100A, Руководство пользователя

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Multi-instrument setups
R&S
®
SMM100A
441 User Manual 1179.1341.02 ─ 05
9 Multi-instrument setups
R&S SMM100A is rarely used as a standalone instrument. Usually, the instrument is
connected 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 between multi-
ple instruments.
●
etc.
R&S SMM100A 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 ....................................................................................441
● Generating time-aligned baseband signals ...........................................................441
● Control and operation of external instruments ...................................................... 448
● System configuration settings ............................................................................... 455
● Digital baseband input settings ............................................................................. 470
● I/Q analog output settings ..................................................................................... 476
9.1 Synchronizing instruments
For information on the possible scenarios concerning the distribution of reference fre-
quency, test setups and the related settings:
See Chapter 7.9, "Reference oscillator" , on page 311.
9.2 Generating time-aligned baseband signals
In test setups that combine the signal of two or more instruments it is often required
that:
●
The signal generation starts at a defined moment
●
The signal generation starts simultaneously (or with an exactly defined delay) in all
involved instruments.
One possible way to achieve quasi-simultaneous signal start is to trigger the instru-
ments by the same trigger event, for example from a
common trigger source .
Because of the trigger signal propagation time and the signal processing time, how-
ever, this method does not achieve precise time aligned signals.
Generating time-aligned baseband signals