Yes: we are using UHD 3.13.1.0 RC1, with the latest file system image I can try to use lower tx start times to see if the time offset changes with that.
Thanks, Serge On Wed, 7 Nov 2018 at 21:44, Marcus D. Leech <patchvonbr...@gmail.com> wrote: > On 11/07/2018 09:31 PM, Serge Malo wrote: > > Yes: > We only use one streamer for all RF outputs, and send time_spec with each > call to the streamer's send method. > We reset the internal time with set_time_unkown_pps(0), and program the > first samples to be streamed at a time of 0.800s. > It is basically the same code we used on the X300/X310. > > Thanks, > Serge > > Well, that is quite strange--the magnitude of the time offsets is larger > than I would expect. > > Perhaps someone from the N310 team can comment? > > Serge, are you using the latest UHD and system image versions for the N310? > > > > On Wed, 7 Nov 2018 at 21:03, Marcus D. Leech via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> On 11/07/2018 08:53 PM, Serge Malo via USRP-users wrote: >> >> Hi all, >> >> We are trying to send 4 synchronous signals from the 4 Tx ports of the >> N310. >> We are using UHD 3.13.1.0 RC1 under Ubuntu. >> Central Freq = 1575.42 GHz and 1227.6 MHz >> Master Clock rate = 153.6 MHz >> >> We would expect to have less than 3ns offset between all TX ports of the >> N310, like we do with the X300/X310. However, we have measured 4700ns >> between TX RF ports 0 and port 2. >> We have tried the next things with no more success: >> - Sampling rates of 25.6MSps, 38.4Msps, 76.8Msps >> - Init with the device options "init_cals=ALL" and "force_reinit=1" >> - Use the internal GPSDO >> - Use clock_source=external and time_source=external (from an Octoclock). >> >> Can you tell us: >> -What time offset between TX RF ports we should expect to achieve? >> -Is there anything else we can try to reduce this offset to less than 3ns? >> >> Best regards, >> Serge >> >> >> How are you setting up your TX streamer? Is it time-tagged to start at >> a particular device time? >> >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> > >
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