With an X310, the DRAM FIFO is included by default in the multi_usrp object (at least for UHD 3.15 and earlier). If you DON'T want it, you have to use a startup arg to skip it (something like SKIP_DRAM=1). Rob
On Fri, May 1, 2020 at 2:18 PM Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 05/01/2020 01:35 PM, Jerrid Plymale via USRP-users wrote: > > Brian, > > > > Thank you for the quick response! I will try the DRAM FIFO and see if that > works. As I am working from home at the moment I do not have access to a > spectrum analyzer, Is there anyway I can use any of the QT GUI blocks in > gnuradio to determine a rough estimate? I know that the values you set are > just values and that you have to determine how they correspond to actual > values, but is there a way to do that mathematically? Determining metrics > for this project have definitely been a struggle me so far. > > > > Best Regards, > > > > Jerrid > > If you're using the multi_usrp interface via Gnu Radio, then the DRAM FIFO > won't be directly visible to you. What sample rate are you trying > to sustain? Can you share your flow-graph with us? > > Underruns mean that your host CPU isn't "keeping up" with the sample-rate > demand from the X310, and if that is an ongoing thing, then no > amount of buffering will help. > > > > > *From:* Brian Padalino <bpadal...@gmail.com> <bpadal...@gmail.com> > *Sent:* Friday, May 1, 2020 10:28 AM > *To:* Jerrid Plymale <jerrid.plym...@canyon-us.com> > <jerrid.plym...@canyon-us.com> > *Cc:* usrp-users@lists.ettus.com > *Subject:* Re: [USRP-users] Setting up an X310 as a signal generator > > > > On Fri, May 1, 2020 at 1:23 PM Jerrid Plymale via USRP-users < > usrp-users@lists.ettus.com> wrote: > > Hello All, > > > > So I have been trying to set up a USRP X310 as a signal generator for > about a week now, and I’m having some issues. Currently I am using > gnuradio-companion to develop the functionality. I have three sets of > signal sources that are of float type, creating the I and Q values that get > passed to a float to complex block. The output of the three float to > complex blocks go to an add block, which then outputs to a USRP sink. > Currently, the first problem is with underruns, I’m not getting a lot of > them however I am getting breaks in the signal when I pass it to a second > USRP X310. What would be the best approach to make sure my signal is coming > in strong to the second USRP? I am also having issues with increasing the > power of the signal when it is received, is this mainly controlled by the > gain value on the USRP source in gnuradio? What can I do to get my incoming > signal to have more power? > > > > You can try placing a DRAM FIFO in your transmit flow graph as the first > thing. That should ensure some tens of milliseconds worth of buffering for > your signals and allow for some host jitter without underruns. > > > > Do you have an external spectrum analyzer or something that can tell you > the power output of the first radio? > > > > The receivers should be able to be saturated by your transmitter, so > there's definitely a gain issue somewhere. > > > > Brian > > > _______________________________________________ > 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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