[USRP-users] help: USRP1 + WBX 50-2200

Marcus Müller marcus.mueller at ettus.com
Wed Dec 10 12:27:06 EST 2014


Hello SKA15,

nice meeting you here :)

There is one thing that is most probably easy to solve: We're seeing a
lot of 'O', meaning overflow, which means that your system can't cope
with the samples that the USRP1 is producing fast enough. What is the
sampling rate you use in the usrp_source block? The USRP1, bound by USB2
speeds, can't really produce very high sampling rates, so unless the PC
you are using to do this is really slow, this points to your sound
card's sampling rate being significantly slower than the sample rate the
USRP pushes through the flow graph. Do you resample to match your sample
rate to the one you use for your alsa sink? Which one is that?

The "not being able to tune to 88.1MHz" warning is indeed strange; could
you run "uhd_usrp_probe" on a console and attach the textual output of
that command?

Greetings,
Marcus

On 12/10/2014 03:53 AM, Thesis 2015 via USRP-users wrote:
> Good day,
>
> We are beginners using the USRP1 with WBX v.3 50-2200 daughterboard and GNU
> radio Companion version 3.7.5.1 with UHD_003.008.000-18-g864f84b5 installed
> on Ubuntu 14.04 LTS operating system. Our goal in using these is to create
> an SDR WBFM receiver.
>
> We have followed what was done in the video posted by the ettus research (
> http://www.ettus.com/kb/detail/sdr-for-beginners-building-an-fm-receiver-with-the-usrp-and-gnu-radio)
> but have encountered some problems. As we ran the GRC file, both the fft
> plot and scope plot appeared but all we could hear are static sounds
> together with the script shown below:
>
> Executing: "/media/thesis/Data/Downloads/Thesis/FM Reciever using
> GRC/fm_example.py"
>
> linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.000-18-g864f84b5
>
> Using Volk machine: sse4_1_64_orc
> -- Opening a USRP1 device...
> -- Loading FPGA image: /usr/local/share/uhd/images/usrp1_fpga.rbf... done
> -- Using FPGA clock rate of 64.000000MHz...
> WARN: Sensor 'lo_locked' failed to lock within timeout on channel 0.
>
> UHD Warning:
>     Tune Request: 88.100000 MHz
>       The requested RX frequency is outside of the system range, and has
> been clipped:
>         Target Frequency: 88.100000 MHz
>         Clipped Target Frequency: 0.000000 MHz
>       Successfully tuned to 0.000000 MHz
> INFO: Audio sink arch: alsa
> OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
>>>> Done
> We are hoping that you could help us with this problem. Thank you.
>
> -SKA15-
>
>
>
> _______________________________________________
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> USRP-users at lists.ettus.com
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