Hi all


I’d like to build up 8X8 MIMO system using 4 USRP X310.

To synchronize time&freq. between all of them, I used to use a function
generator to feed both 1 PPS and 10 MHz reference clock to them.

Today, I got an Octoclock which I thought it is able to provide both
synchronization signal, but it is said that “For the OctoClock, there is no
internal timing or clocking source, so the OctoClock will always use
external 10 MHz and 1 PPS sources, regardless of the position of the switch.”
in the UHD manual.



So, I plan to use one of the X310 to feed the synchronization signal to the
Octoclock REF&PPS input and connect other X310s to the REF&PPS output, like
the block diagram below.



[image: 內置圖片 1]

1.

I use the LTS version of UHD (3.9.6).

And I use the commands like:

     //Lock mboard clocks

     tx_usrp->set_clock_source("internal",0);

     tx_usrp->set_clock_source("external",1);

But it always show the error message:

Error: RuntimeError: Reference Clock PLL failed to lock to external source.



I wonder if the commands or my thought were wrong or this function is not
supported?Because I found some discussions (March, 2017) in the mailing
list talked about the X310 is not supported for daisy-chaining. By the way,
is X300 not supported neither?





2.

The other problem is that when I use a terminator to terminate the TX/RX
port, I can still discover the signal through the spectrum analyzer by
connecting an antenna. Is the signal leaked from somewhere? And how to
prevent it?





Thanks in advance!

Jorge
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Reply via email to