If you're getting long strings of 'U', this means a *gross* sample-rate mis-match somewhere in your flow-graph, rather than the more-subtle "two clock" problem.
Make sure that everything agrees internal to the graph about sample-rates, and, perhaps more importantly, that your audio *hardware* is capable of delivering the desired rates. On 2015-03-17 10:30, Larry Van Der Jagt via USRP-users wrote: > Hello: > > Can anyone point me to some "color" on how to work with the Audio Source. I > am working examples to transmit FM Audio and have problems with Underruns on > the UHD:USRP Sink. > > The examples (from files.ettus.com/tutorials/Lab_5.grc [2] and others) I am > running select Audio Source Arch:alsa and this seems to be a problem. > > I have tried to replace the Device name with plughw:0,0 as suggested in the > documetnation, but this does not seem to have an impact on the choice of > Audio arch: alsa > > If I replace the audio source with a signal source at the same sample rate > all is well, but the Audio Source implements UUUUUUUUUUUU. > > Using the suggestion of having the USRP expect a bit lower rate than the > audio can deliver seems to implement nearly limitless delay .... the voice is > received but only after a very long ... many seconds delay ... .... > > At this time I am using a B210 connected via USB3 to an I7 with plenty of > memory running Ubuntu 12.04 .... I have similar issues trying to use an E310 > as the transmitter ... > > Any direction would be appreciated. > > LVDJ > > _______________________________________________ > USRP-users mailing list > usrp-us...@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com [1] Links: ------ [1] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com [2] http://files.ettus.com/tutorials/Lab_5.grc
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