hello,
I use four usrp-2945 as synchronous acquisition system, CDA-2990
provides internal reference clock and PPS to four usrp-2945, and pxie-5651 and
pxie-5652 are used to provide two-stage local oscillator for four USRPs. Now I
use two usrp-2945 to collect the data of two channels (one channel for each)
and calculate the phase difference between the two channels. If I use UHD
4.1.0.1, after multiple acquisition, I find that there are four kinds of phase
differences, and the phase differences are roughly 90 degrees, 180 degrees and
270 degrees. For example, the four phase differences are 4.5 degrees, 95.53
degrees, 189.51 degrees and 275.49 degrees respectively. If I use UHD 3.15.0.0,
there is only one phase difference.
Setup Details
1.CDA-2990 provides internal reference clock and PPS to four usrps.
2.Pxie-5651 and Pxie-5652 are used to provide two-stage local oscillator for
four USRPs.
Expected Behavior
Using UHD 4.1.0.1, there is only one phase difference.
Actual Behaviour
There are four phase differences using UHD 4.1.0.1.
Steps to reproduce the problem
After synchronizing the reference clock, PPS and lo, use UHD 4.1.0.1 to collect
one channel of different USRP and calculate the phase difference.
can anybody help me?
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