Hi,Might sound ridiculous, but try tuning to the frequency of interest twice before doing the collection. The X310 command buffer is smaller than it needs to be to handle tuning the TwinRX, so if you don't tune twice, you'll see phase ambiguity.
-Dustin On 11/17/21 04:03, 陈煜 wrote:
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 problemAfter 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? _______________________________________________ USRP-users mailing list [email protected] To unsubscribe send an email [email protected]
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