Hi Marcus,
Thanks for your response.
"Are you setting up clocking identically for both USRPs? That is setting the
reference clock to "external" and the 1PPS source to "external" on both
devices? Are you using a single multi_usrp object for all RX channels?"
Yes, I use multi_usrp
multi_usrp::make('addr0=192.168.12.2,second_addr0=192.168.13.2,addr1=192.168.14.2,second_addr1=192.168.15.2,master_clock_rate=184.32e6')
"external" set for both ref and
pps:usrp->set_clock_source("external")usrp->set_time_source("external")
I think this should automatically set both devices.
"What type of daughtercards are in your X310?"
UBX
Kind regards.
On Wednesday, 1 May 2024 at 14:19:44 BST, Marcus D. Leech
<patchvonbr...@gmail.com> wrote:
On 01/05/2024 08:25, zhou via USRP-users wrote:
Hi All,
I am trying to use 4Rx and 4Tx antennas from two X310 USRPs. I hope the
received signals have stable phase relationship but they don't seem to be. I am
wondering why and how to fix it.
I measured the phase using the connection as below:
cos(t)+i*sin(t) signal is split into and received on four Rx antennas. Two
X310s are connected to the same OctoClock for 10MHz Ref and PPS. Tx and Rx
commands are all timed. The measurement results are as below:
The Tx signal is continuous during test. I measured phase every second for 20
sec. In the 2nd USRP, the phases are stable on both antennas while it is not in
the 1st. If I change the Tx signal to the 1st USRP, then the results swap -
phases become stable in the 1st USRP and unstable in the 2nd.
My first though was that there might be small CFO between USRPs even though
both are connected to the OctoClock, but CFO should have caused linear change.
Here, the phase offset is not linear and kind of random within 20 second
measurement.
What can be the reason? Any suggestion will be appreciated.
Kind regards, H. Are you setting up clocking identically for both USRPs?
That is setting the reference clock to "external" and the 1PPS source to
"external" on both devices? Are you using a single multi_usrp object for all
RX channels?
What type of daughtercards are in your X310?
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