Note
Synchronizing multiple USRP RIO devices requires a CDA-2990
accessory.
Ensure that all hardware is set up as previously described.
1. Connect the REF IN port of the USRP RIO device to the first 10 MHz OUT port of
the CDA-2990 using a standard SMA (m)-to-SMA (m) cable.
2. Connect the PPS TRIG IN port of the USRP RIO device to the PPS OUT port of
the CDA-2990 using a standard SMA (m)-to-SMA (m) cable.
3. Repeat steps 1 and 2 to synchronize additional USRP RIO devices using the
additional ports on the CDA-2990 (optional).
The completed hardware setup for two USRP RIO devices is shown in the
following figure.
Figure 3. USRP Device Synchronization Configuration
2
CDA-2990
Designed by Ettus Research
Designed by Ettus Research
3
4
5
6
2
1
7
8
7
8
3
4
5
6
2
1
PPS OUT
10 MHz OUT
PPS OUT
POWER
GPS LOCK
PPS
STATUS
EXTERNAL
INTERNAL
ETHERNET
GPS ANT
INPUT
PRIMARY REF
INTERNAL
EXTERNAL
EXT 10 MHz
INPUT
EXT PPS
INPUT
POWER
8 Channel Clock Distribution Module
6
–
15 V
6 W MAX
0
1
PWR
REF
IN
PPS
OUT
TRIG
5V DC
REF
OUT
1G/10G ETH
3.3 V
+15 dBm
MAX
9-16V DC
7.5 A MAX
SFP+Ports
PCIe x4
TRIG
3.3V
IN
5V MAX
PPS
GPS
ANT
–15 dBm
MAX
0
1
PWR
REF
IN
PPS
OUT
TRIG
5V DC
REF
OUT
1G/10G ETH
3.3 V
+15 dBm
MAX
9-16V DC
7.5 A MAX
SFP+Ports
PCIe x4
TRIG
3.3V
IN
5V MAX
PPS
GPS
ANT
–15 dBm
MAX
1
1. SMA (m)-to-SMA (m) Cables
2. SMA (m)-to-SMA (m) Cables
Preparing the USRP-2945 for LO Sharing (Optional)
Complete the following steps to prepare a single USRP-2945 device to share LOs
among all four of the device's channels.
© National Instruments
11
USRP-2940/2942/2943/2944/2945 Getting Started
