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>). > 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 >
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