I wonder if this is just because in RFNoC the DDC is explicitly visible, so you have to program it to account for synthesizer step size?
Sent from my iPhone > On Oct 1, 2019, at 12:52 PM, Jason Matusiak via USRP-users > <usrp-users@lists.ettus.com> wrote: > > I have an issue that is very odd to me. I have tried two different X310s > with different daughter cards and they are all exhibiting this behavior. It > feels like I am doing something stupid, but I can't quite figure out what. (a > picture is attached) > > If I have a usrp source connected to a freq sync, everything is golden. If I > instead use an RFNoC source connected to a DDC to the freq sync, I get > inconsistent results. I think the settings are the exact same, but it feels > like the radio is not being reset properly. Sometimes it tunes to where I > tell it to and I can see my signal of interest perfectly, other times it > off-tunes anywhere from a few MHz to way off the screen. Subsequent retuning > seems to actually make changes to the tune frequency, but not consistently > (maybe I need to tune to 943MHz one time to mimic a tune to 910MHz. the next > time I would have to tune somewhere else). > > I am using the stock image and have tried with both XG and HG (though I am > mostly testing with XG). > > UHD_3.14.1.HEAD-0-g5491b80e > > GR v3.7.13.4 > <Screenshot from 2019-10-01 12-51-07.png> > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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