[USRP-users] problem with USRP example on X310 with CBX-120

Michael West michael.west at ettus.com
Fri Oct 24 17:55:52 EDT 2014


Hi Jim,

An experimental UHD patch was sent to your colleague to address the
calibration issue.  Please let me know if you need the patch sent to you
directly and I will get it to you.

Best regards,
Michael

On Thu, Oct 23, 2014 at 10:40 AM, Jim Hunziker via USRP-users <
usrp-users at lists.ettus.com> wrote:

> Marcus Leech responded to me off-list that I was using gain settings that
> were too low. Setting them to 10 greatly improved my signal, though there's
> still a carrier component that's bigger than my signal and not getting
> removed. A colleague tells me he's working with Ettus regarding this
> problem.
>
>
> --
> Jim Hunziker
> BCI Systems and Software Engineering
> (973) 348-9299
> jhunziker at bcisensors.com
>
> On Wed, Oct 22, 2014 at 4:42 PM, Jim Hunziker <jhunziker at bcisensors.com>
> wrote:
>
>> It looks like some of my problem was plotting abs(sig_c) rather than
>> real(sig_c), but the signal still doesn't look great.
>>
>>
>> --
>> Jim Hunziker
>> BCI Systems and Software Engineering
>> (973) 348-9299
>> jhunziker at bcisensors.com
>>
>> On Wed, Oct 22, 2014 at 12:15 PM, Jim Hunziker <jhunziker at bcisensors.com>
>> wrote:
>>
>>> Hi. I have an X310 with a CBX-120 and a GPSDO, and I'm running the
>>> txrx_loopback_to_file example with UHD version 3.7.3 like this:
>>>
>>> ./txrx_loopback_to_file --tx-args addr=10.10.10.90 --nsamps=250000
>>> --tx-rate 2500000 --rx-rate 2500000 --tx-freq 56000000
>>> 00 --rx-freq 5600000000 --rx-ant CAL --wave-type SINE --ref internal
>>> --wave-freq 1000
>>>
>>> (It makes no difference if I use the RX2 antenna and a loopback cable.)
>>>
>>> With a sampling rate of 2.5 MHz and a sine wave of 1 KHz, I expect to
>>> see a sinusoidal cycle every 2500 samples. I'm plotting them with GNU
>>> Octave and the following commands:
>>>
>>> fid = fopen("~/uhd/host/build/examples/usrp_samples.dat", "rb");
>>> [sig, count] = fread(fid, Inf, "int16");
>>> sig_c = sig(1:2:end) + j * sig(2:2:end);
>>> plot(abs(sig_c));
>>>
>>> The signal seems very noisy, and it's pretty much gone towards the end
>>> of the capture. Am I doing something wrong?
>>>
>>> --
>>> Jim Hunziker
>>> BCI Systems and Software Engineering
>>> jhunziker at bcisensors.com
>>>
>>
>>
>
> _______________________________________________
> 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/20141024/4fd16478/attachment-0002.html>


More information about the USRP-users mailing list