Rohde & Schwarz SMM100A, User Manual

Page: 442 / 1088

Multi-instrument setups
R&S
®
SMM100A
442 User Manual 1179.1341.02 ─ 05
To generated synchronous and time aligned signals with multiple instruments, use
the primary-secondary instrument mode .
This section explains how to use the provided settings to define the signal generation
start in the basebands of
multiple instruments .
● Connecting multiple instruments in primary-secondary instrument mode .............442
● Triggering several instruments with a common trigger signal ............................... 447
9.2.1 Connecting multiple instruments in primary-secondary instrument
mode
About the primary-secondary instrument mode
When connected in primary-secondary instrument mode, two or more R&S SMM100A
or one R&S SMM100A and several other signal generators such as R&S SGT or R&S
SMBV can generate synchronous and time aligned signals.
In this mode, the primary instrument generates and outputs a dedicated synchroniza-
tion signal (Sync Out), that has to be fed into the secondary instrument. The secondary
instrument detects and demodulates the signal, and retrieves both the baseband clock
and the trigger signal from it. Secondary instruments can forward the received synchro-
nization signal (Sync In) and output it to trigger further secondary instruments.
Synchronization signal
The synchronization signal is a 50 MHz signal that carries the trigger pulse modulated
on it. Hence, it provides
joint triggering and baseband clock synchronization at the
same time.
Final time alignment can require adding I/Q or trigger delay. However, once synchroni-
zation is achieved, the primary-secondary instrument mode ensures reproducibility of
triggering, if the used waveform, sample rate and cabling are not changed.
Test setup
Regarding the synchronization signal , the instruments can be connected (cascaded)
in a daisy chain (see Figure 9-1 ).
Also, all instruments in the setup have to use the same reference frequency . You can
distribute the internal reference frequency of one of the instruments. Distribution is
independent for primary or secondary instruments. Alternatively, supply all instruments
with an external reference frequency source.
9.2.1.1 Multi-instrument settings
Access:
► Use one of the following:
● Select "Taskbar > System Config > System Configuration > Multi Instrument"
Generating time-aligned baseband signals