Thank you for the quick reply, that did the trick, at least half way. Now I’m struggling with the random 180° phase offset between the front end pairs, obviously generated by the AD9371 chip according to my research. Is there any best-practice in detecting this phase shift that does not involve an additional reference signal source?
> Am 22.03.2019 um 14:17 schrieb Marcus D. Leech via USRP-users > <[email protected]>: > > On 03/22/2019 05:31 AM, Janos Buttgereit via USRP-users wrote: >> Hi, >> >> after having struggled a lot with network config issues I finally got out >> N310 up and running. We chosed it for an application that needs perfectly >> constant phases between all four channels to build up DOA estimation >> applications. >> >> I’ve set up an N210 as a signal source, outputting a sine round about 1.5GHz >> feeding a 4-way splitter that than feeds all four input channels of the >> N310. A Rhode&Schwarz signal generator outputting a 3GHz sine wave feeds a >> two way splitter that is connected to both external rx LO inputs. >> >> From this setup I expect all four channels to maybe have a static phase >> offset that does not change over time. However, it can be noticed that the >> pairs of channels 0 and 1 and the pairs of channels 2 and 3 show those >> behavior but both pairs drift against each other over time. Any idea of what >> could be wrong with this setup? >> >> I attached the GNURadio flow graph for this setup. >> >> Thanks in Advance! >> > Change the "Sync" option to "Unknown PPS". Why this is required is a bit of > a mystery, but another user experienced the same issue. > > The N310 is conceptually two radios in a single box, and each radio within > the FPGA has its own "timekeeper". For some reason, unless those > "timekeepers" are started synchronized with each other, sample timestamps > drift relative to one another. This should not be the case, but > it appears to be. > > > > > _______________________________________________ > USRP-users mailing list > [email protected] <mailto:[email protected]> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > <http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com>
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