Cherif, Great news! Congrats on the fix!
Cheers, Daniel On Mon, Oct 7, 2019 at 9:48 AM Cherif Diouf via USRP-users < usrp-users@lists.ettus.com> wrote: > Daniel, > > > The problem was finally solved. It was from both my software and my > hardware development. > > -> in fact in the software I used the set_time_next_pps() call from the > device3 object to synchronize the vitatime counter with the PPS signal, but > later on I would also create a rfnoc_streamer object to be able to use > the rf frontend. This would somewhat modify the vitatime value and > desynchronize my local counter with the vitatime counter causing random > offset between the two counters. > > -> The second problem was linked to the cvita_hdr_encoder which was not > properly set, Leading the frontend to transmit asap, I guess. > > > So from both these issues I could be from time to time off by one sample/5 > ns at the transmitter. > > Now that's old story ! > > > Many thanks > > > Cherif > > > > > __________________ > > Fabian, I had a hunch it was just the 3.3V part--thanks for clarifying! > > Cherif, the DAC interface timing (and for that matter, the ADC timing) > should be fairly tight. What you're seeing is expected and matches the > numbers we designed it to. The FPGA constraints are intentionally tight to > provide some extra margin at the DAC. Since this is all in the same X310, > you could start by isolating the various components of the design using the > front-panel GPIO connector. Run a trigger from each of your custom blocks > to the GPIO and see if they line up on a scope. If they don't, then you > might have a baseband timing issue (with how timed commands are interacting > with your blocks). If they line up, then it points to a timing failure in > the DAC. > > -Daniel > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > -- Daniel Jepson Digital Hardware Engineer National Instruments O: +1.512.683.6163 daniel.jep...@ni.com
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