Wait, what? I've been using REF OUT for years now. What am I missing? What does "aren't actually fully supported" mean?
On Tue, Oct 16, 2018 at 8:57 AM Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 10/16/2018 07:44 AM, Francois Quitin via USRP-users wrote: > > Dear all, > > > > We encountered a small problem when we try to build a 4-element MIMO array > with two X310 (equipped with UBX daughterboards). We are working on > UHD-3.10.3: > > - When we use an octoclock to provide the 10 MHz Ref and the PPS > to both X310, the phase of each receiving front-end stays nicely constant > (see octoclock.png). The Ref Source and Time Source are set to “external” > in GNU Radio (the points represent a measurement taken every ten seconds) > > - When we use the 10 MHz Ref Out and PPS Out from one X310 and > feed it to the Ref In and PPS In of the other X310, we observe a drift in > the phases of the channels from the second X310. This is shown in the graph > daisyChain.png, where we take one point every ten seconds. We configured > GNU Radio to set the Ref Source and Time source of the first USRP to > “default”, the ones of the second USRP to “external”. > > > > This drift is something more severe, sometimes less, but it’s always > present. Any idea why we observe this? > > > > Many thanks, > > > > François > > > > --- > > Francois QUITIN > > Assistant Professor > > > > BEAMS Dpt. – Embedded Electronics > > Brussels School of Engineering > > Université Libre de Bruxelles (ULB) > > > > Web https://sites.google.com/site/fquitin2/ > > Phone +32 2 650 2829 <+32%202%20650%2028%2029> > > > > The REF OUT and PPS OUT ports aren't actually fully supported in the FPGA > code, and we don't, at this point, recommend their use. > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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