[USRP-users] issue with rfnoc fft size

Jonathon Pendlum jonathon.pendlum at ettus.com
Mon Jul 17 12:47:55 EDT 2017


Hi,

Your Ethernet packet size has to be large enough to fit the entire FFT
output in a single packet. Try setting your MTU to 9000.

Jonathon

On Mon, Jul 17, 2017 at 8:38 AM, Sanjoy Basak via USRP-users <
usrp-users at lists.ettus.com> wrote:

> Hello experts,
> I am trying to use RFNoc fft examples (rfnoc_fft.grc). I started with the
> gr-ettus examples. However, I am having some problems with the fft size. In
> the grc block, I find the option to choose 4096 fft size. However, with
> hardware I could only work fft size 128 and 256. If I use 512/1024 fft
> size, I get the timeout (following message) with signal source.
>
> timeout on chan 0
> timeout on chan 0
> timeout on chan 0
> timeout on chan 0
>
> Similarly, if I am receiving with RFNoc radio, with fft size 256 I see the
> correct output. However, with 512 fft size I get the following output.
>
> Ooverrun on chan 0O
> overrun on chan 0
> Ooverrun on chan 0O
> overrun on chan 0
> Ooverrun on chan 0O
> overrun on chan 0
> Ooverrun on chan 0
> O
>
>
> I also used the following commands to increase rf buffer size, however,
> the results are the same.
> sudo sysctl -w net.core.rmem_max=33554432
> sudo sysctl -w net.core.wmem_max=33554432
>
> I attached the uhd_usrp_probe output.
>
> I am using ubuntu 16.04. I conected the X310 with 1Gb ethernet cable.
> My hardward setup is X310/UBX-160. I am also attaching the grc file.
> Please let me know what is going wrong.
>
> Best regards
> Sanjoy Basak
>
>
> <https://mailtrack.io/> Sent with Mailtrack
> <https://mailtrack.io/install?source=signature&lang=en&referral=sanjoybasak14@gmail.com&idSignature=22>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20170717/d3026aaa/attachment-0002.html>


More information about the USRP-users mailing list