Update / Fix: Just to let anyone know who might run into this... Using UHD release 003.009.006 (currently, I'm tracking UHD-3.9.LTS) seems to fix this problem. It can be tested by running Jimmy's noise_mult1_tx.grc flowgraph. Reducing the sample rate from 4e6 to 1e6 (on a slower machine that had a harder time keeping up with the noise source block's demands at that rate) showed to not interfere with whether or not this problem would manifest itself.
- Rich On Mon, Feb 6, 2017 at 4:58 PM, Collins, Richard < [email protected]> wrote: > Hello, > > I'm having what seems like the same problem as Jimmy reported in the > USRP-Users back in November. (see forwarded portion of email, since I > wasn't able to find any posts by him in discuss-gnuradio since then). > > All I'm doing is generating continuous samples (fc32), that goes into a > "Rational Resampler" block, and then directly into a UHD USRP Sink block. > I'm using an X310 with UBX-160's as well. > > When I don't use the UHD USRP Sink, but still have the Rational Resampler > block, everything works fine. When I don't use the Rational Resampler > block, but still send use the UHD USRP Sink block, everything works fine. > > When i do use both in combination, the UHD Sink block does spit out a > bunch of U's (maybe a couple lines worth) at the beginning of transmission, > accepts about 3 seconds worth of items, and the stop requesting items. I > see the flowgraph running, but nothing is moving (as can be seen by custom > printf messages that say how much is being consumed and returned, or by > using a QT GUI Sink, and seeing it stop). No errors are thrown, except that > after I stop the flowgraph, one 'O' is thrown. That might not indicate > anything, though. > > Here's what I'm working with: > UHD 003.010.001.HEAD-0-gc705922a (tag "release_003_010_001_001") > GNU Radio v3.7.10.1-201-g884eddf4 (branch origin/maint) > > Please let me know if more information is needed. > > Thanks, > - Rich > > ---------- Forwarded message ---------- > From: Jimmy Chau via USRP-users <[email protected]> > Date: Wed, Nov 9, 2016 at 9:15 PM > Subject: [USRP-users] USRP X310 with UBX-160 - transmit freezes with > certain GNURadio flowgraphs > To: [email protected] > > > Hi, > > Using certain GNURadio flowgraphs (created in gnuradio-companion) with the > USRP X310 and the UBX-160 daughter card, I’m encountering a problem where > the radio stops transmitting, and signals/items seem to stop being > generated/propagating through the flowgraph. No error would appear when > this happens (except sometimes, but not always, a burst of underflow “U” > appearing all at once, shortly before before the transmit signal stops). > > I’ve tried to narrow down the cause of this problem, and I’ve attached my > simplest gnuradio-companion flowgraph (noise_mult1_tx.grc) that reliably > triggers the problem within about 10 seconds. This flowgraph consists of a > Noise Source, attached to a Multiply Const (that multiples by 1), attached > to the UHD USRP Sink. I’ve also attached a QT GUI Sink to the input of the > UHD USRP Sink to view the signal. > > Eventually, the QT GUI Sink shows that the signal stops (i.e., stops > updating), and if I use the RX2 input of the UBX-160 to receive the > transmitted signal (through a SMA cable and a 20dB attenuator), the > received signal would simply be the noise floor (i.e., no transmitted > signal present). However, the receiver would continue update. > > I haven’t been able to figure out exactly what’s causing this problem. If > I remove the Multiply Const block (and connect the Noise Source directly) > or if I replace the Noise Source with a Signal Source (a sine wave), the > problem does not appear, and the transmitter works for as long as I let it > run. > > This problem would also appear if I try to add the outputs of two separate > NBFM Transmit blocks (with a Rational Resampler), using an Add block, even > without any Multiply Const block present. The setup that causes this > problem is arranged as: > > [Signal Source] —> [NBFM Transmit] —> [Rational Resampler] —> [Add] —> > [UHD USRP Sink] > [Signal Source] —> [NBFM Transmit] —> [Rational Resampler] —> [ ] > > But it doesn’t appear if I try to feed only one NBFM signal into the UHD > USRP Sink block. > > I’ve tried reinstalling uhd and gnuradio using the latest commits from the > "maint” branch (commit edfbbc from Nov 4 for gnuradio 3.7.10.1), but that > did not seem to help. I’m running GNURadio on Ubuntu 16.04.1 LTS. UHD’s > version string is: > linux; GNU C++ version 5.4.0 20160609; Boost_105800; > UHD_003.010.001.000-1-g4594f7d7 > The X310 also has a LFTX daughter card in slot B. > > I’ve tried switching to another computer and removing all other USRPs from > the gigabit Ethernet switch (so only the computer and the USRP X310 are > connected). However, this did not seem to resolve the problem. > Unfortunately, the computer and USRP are positioned so that it’s difficult > to connect them without the switch in between, but I can try to connect > them directly if it might help. > > Any ideas on what the problem might be or suggestions on how to > troubleshoot this? > I can provide additional examples if it would be helpful. > > Thank you for any help! And please let me know if my question would be > better directed towards the discuss-gnuradio mailing list. > > > Best regards, > -Jimmy > > > _______________________________________________ > USRP-users mailing list > [email protected] > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > >
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