VTI Instruments Corp.
APPENDIX B
46
CMX09 or CMX18 chassis are used, the PXI 10 MHz reference clocks can be synchronized using
BNC connectors on the back of each chassis.
Figure 4-8: EMX-2500 Trigger and CMX09 10 MHz Reference
M
ULTIPLE
C
HASSIS
S
YNCHRONIZATION WITH
LAN
E
VENTS
When chassis are geographically separated by a long distance, it may not be practical to connect a
physical trigger and a reference clock line between them. The EMX-2500 makes
EMX-4250/4350/4380s in each chassis an LXI device so they can be synchronized together using
IEEE 1588 clock and LAN events.
When multiple chassis containing EMX-4250/4350/4380s and EMX-2500 controllers are initialized
in a single Digitizer/DSA driver session, they can be automatically synchronized using LAN events
specified by the LXI specification. This is equivalent to synchronizing chassis using a trigger signal,
except a LAN message is used over Ethernet. In this configuration, sampling and timestamp clocks
are synchronized to the IEEE 1588 PTP master chosen by the best master clock (BMC) algorithm.
The PTP master can be an IEEE 1588-capable GPS unit or an EMX-2500s.
IEEE1588
Grandmaster
Ethernet
IEEE1588 Clock
IEEE15
88 Cloc
k
IEE
E15
88 C
loc
k
LA
N
E
ve
n
t C
o
o
rd
in
at
io
n
Figure 4-9: LAN Synchronization
