[USRP-users] Still having problems receiving multiple channels

Derek Kozel derek.kozel at ettus.com
Tue Oct 17 07:43:06 EDT 2017

Hi Janos,

What daughtercards are you using? Can you include the console output of
your program when it runs? It looks like you have useful log messages.


On Tue, Oct 17, 2017 at 11:32 AM, Janos Buttgereit via USRP-users <
usrp-users at lists.ettus.com> wrote:

> Hello everybody,
> I wrote to the mailing list some month ago as I had problems setting up a
> multi_usrp from four USRP N210 with the help of the C++ API. As there are
> other projects with higher priority, I’m just working on the USRP-based
> stuff from time to time, that explains why there is a problem unsolved for
> months now. In the end some specifications changed, so I dropped the N210
> and I’m now working with a pair of X300 devices.
> The problem I still have after having solved a lot of other things with
> your help, is that there’s always only valid data from the first channel.
> To make sure that there is no bug in my fairly big code, I created a simple
> command line application, that just records four channels to four .bin
> files. These files are then loaded in gnu octave In this scenario, both
> X300 devices are clocked and time synced by an external OctoClock and fed
> with the same sine-wave, generated by a Signal Generator and split by a
> power splitter.
> I pasted my code and a plot of what the received data looks like here:
> https://gist.github.com/JanosGit/af51ae66c3a5c8a90119ec5f98e01162
> By the way, a modified version of the rx_multi_samples example which I
> modified to output the samples to a file instead of dropping them showed
> the exactly same result.
> For your Information: I’m working on a fresh Ubuntu installation with the
> X300 devices connected over SFP Cables to a dual 10GBit Ethernet PCIe Card.
> Receiving valid data on all four channels works with the same hardware but
> a slightly older Ubuntu installation on a second computer when using gnu
> radio (never change a running system), so I don’t think there is any
> hardware defect. I just need to up- or downgrade the FPGA Image when
> switching between both systems. While executing the application linked
> above, all four green LEDs underneath the RX2 Ports are lit.
> I’m really looking forward to finding a solution with your help!
> Regards
> Janos Buttgereit
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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