Hi Marcus, I'm pretty sure that the DDC and DUC don't have access to the MB clock and thus have no option but to executed timed commands using the time stamp in the sample stream. Rob
On Tue, Mar 3, 2020 at 12:41 PM Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 03/03/2020 12:08 PM, Sam Reiter via USRP-users wrote: > > For what it's worth, I was able to reproduce the behavior described here, > but didn't get to dig into it much. My leading suspicion would be what Rob > mentioned about timestamping. Lukas' code sets a command time, but I'm not > clear on how timestamp metadata for packets being sent to the radio are > handled. Might be a good question to loop the discuss-gnuradio mailing list > in on? > > Sam Reiter > > Timed commands, I thought, were ALWAYS referred to the motherboard clock, > without regard to timestamps in the stream? > > > > On Tue, Mar 3, 2020 at 10:59 AM Rob Kossler via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> I wonder if the issue is related to a missing time stamp on the baseband >> samples going from GR to UHD. If the stream does not have a time stamp, >> the DUC is unable to apply the timed command because the DUC does not >> really know the time - it must pull the time from the streaming samples. >> This is in contrast to the radio block which does have access to time and >> can apply timed commands by referring to the motherboard clock. >> >> I am not too familiar with GR so I'm not sure how to know if GR is >> putting a time stamp on the streaming samples. >> Rob >> >> On Mon, Mar 2, 2020 at 10:04 AM Lukas Haase via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> Hi Marcus, >>> >>> Thank you that would be amazing! >>> >>> I followed the tutorial and built everything from source: >>> >>> $ lsb_release -a >>> No LSB modules are available. >>> Distributor ID: Ubuntu >>> Description: Ubuntu 18.04.4 LTS >>> Release: 18.04 >>> Codename: bionic >>> $ uname -a >>> Linux sdr 5.3.0-40-generic #32~18.04.1-Ubuntu SMP Mon Feb 3 14:05:59 UTC >>> 2020 x86_64 x86_64 x86_64 GNU/Linux >>> $ cd uhd >>> $ git status >>> HEAD detached at v3.15.0.0 >>> $ cd ../gnuradio >>> $ git status >>> HEAD detached at v3.7.14.0 >>> >>> >>> Thank you! >>> >>> Lukas >>> >>> >>> >>> PS: For some reason I sometimes do not get responses from this list. I >>> just saw it looking at the mailman archives. Hence I cannot respond (to >>> keep headers intact) but need to create a new message and manually "quote". >>> I hope that still preserves the context somehow. >>> >>> >>> >>> Marcus Leech wrote: >>> > On 02/28/2020 01:01 PM, Lukas Haase via USRP-users wrote: >>> >> Hi again, >>> >> >>> >> I created a minimum example (gnuradio) that shows the issue described >>> below. >>> >> To summarize: Retuning to a different dsp frequency on an USRP X310 >>> (+UBX160) does not work (command ignored) ONLY if a timed command (in >>> future is used). >>> >> The code shows it in a simple manner. Commenting out the single line >>> with set_command_time makes the example work. >>> >> >>> >> I am absolutely out of ideas and would appreciate any input! >>> >> >>> >> Best, >>> >> Lukas >>> > Lukas. >>> > >>> > Thanks for sticking with this. I'll have a discussion with Ettus R&D >>> to >>> > see if this is a known issue and/or if there's a workaround. >>> > >>> > Remind me which version of UHD you're using? >>> >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> > > > _______________________________________________ > USRP-users mailing > listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >
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