Hi Jeff, thanks for clarifying!
Yes, that should work. Also, your GR version definitely has support for SOB/EOB. Generally, I'd expect this to work; only misconception I see is that the Sink doesn't start sending when it sees the EOB; it starts sending at SOB, and stops expecting and sending samples to the USRP at EOB. Could you try replacing your very "spikey" signal with something like a sine, so to see whether we might be seeing turn of/off behaviour? Best regards, Marcus On 21.01.21 16:34, Jeff S wrote: > Thanks, Marcus. > > Of course, I forgot the important version information. I'm currently using > v3.7.13.5. We > are also doing some RFNoC work, which we had some issues upgrading a while > back, so we > were holding off until it matured more. I'll ask our team if they want to > try and upgrade > to 3.8 again. > > I'm sure my description wasn't clear, so I'll try and clarify a little better > based on > your feedback. > > I created the Random Source, and it is sending approximately 10,000 samples > to the UHD > USRP Sink as one message, with a tx_sob at the start and a tx_eob at the end. > My thought > was that the sink would not transmit anything until the EOB was received. > The way > GNURadio seems to be running, I'm getting [noutput_items == 4096], so it > takes three calls > to the work function to deliver all 10K samples of one message to the Sink. > I only want > one burst from the sink of those 10K samples. What I am receiving seems to > be three > transmissions that make up the one sample. The length of the three > transmissions seem to > correspond to the value of noutput_items I was seeing. > > The mention of 100 ms between bursts was only indicating how fast the > modulator was being > requested to transmit a single message. So if I only requested one message, > there would > have been one group of three signals seen in the Rx signal. > > Hope that clarified what I was trying to convey a little better. > > Regards, > Jeff > > > > ------------------------------------------------------------------------------------------ > *From:* Marcus Müller <marcus.muel...@ettus.com> > *Sent:* Thursday, January 21, 2021 9:06 AM > *To:* Jeff S <e070...@hotmail.com>; usrp-users <usrp-users@lists.ettus.com> > *Subject:* Re: [USRP-users] SOB/EOB Burst Mode on X310 Splitting Signal > > Hi Jeff, > > which version of GNU Radio are you using? Judging by the looks of your flow > graph it's the > (now legacy) 3.7, but *if* I remember correctly (it's really been a while), > the SOB/EOB > functionality appeared *somewhen* in 3.7.x; it might be worth trying your > exact same > application in GNU Radio 3.8 (or 3.9). > > Conceptually, it's important to note that after tx_sob you need to supply the > full burst > of samples: I think you're doing that, but then again, you say you get three > data bursts > 100 ms apart, so I'm not sure about that, to be honest. The USRP sink can't > guess that you > want three bursts of samples to be sent as one; it starts streaming as fast > as you supply > it data after the SOB, and will tell you you're late or too slow at supplying > data (tG/U > printed to your console) if you don't give it 10 million samples a second, > until it gets > an SOB. > > Best regards, > Marcus > > > On 21.01.21 15:53, Jeff S via USRP-users wrote: >> I am attempting to use burst mode on an X310. I'm generating a random >> signal from one >> X310 and receiving it on another. My simple flowgraph is: >> >> I can see the tx_sob and tx_eob tags, set to true, from the time sink: >> >> >> where I verify that I can see the EOB, followed by a new SOB in the next >> message (both set >> to true, according to >> https://www.gnuradio.org/doc/doxygen/classgr_1_1uhd_1_1usrp__sink.html > <https://www.gnuradio.org/doc/doxygen/classgr_1_1uhd_1_1usrp__sink.html> >> <https://www.gnuradio.org/doc/doxygen/classgr_1_1uhd_1_1usrp__sink.html > <https://www.gnuradio.org/doc/doxygen/classgr_1_1uhd_1_1usrp__sink.html>>). > But when I am >> receiving the signal, the message seems to be broken up into three different >> transmissions >> instead of one burst: >> >> >> >> I'm transmitting a message every 100 ms, which seems to correspond to the >> start of the >> three messages. >> >> Analyzing the modulator in a debugger indicates that there are three times >> that the work >> function is called to build the message, which may correspond to the three >> messages seen >> in the signal, but I'm not sure why the tx_sob and tx_eob tags are not being >> followed. >> Maybe I may just have a major misunderstanding of how burst mode works. >> >> Any ideas on what I may be doing wrong? >> >> Thanks, >> Jeff >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/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
