Hello Ali,

The bandwidth parameter will select the Analog RF filters where possible.
For the X310 the daughterboards do not have configurable filters so you
will have to add a lowpass filter to your flowgraph.

Regards,
Derek

On Thu, May 17, 2018 at 2:10 PM, Ali via USRP-users <
usrp-users@lists.ettus.com> wrote:

> Hi,
>
> I don't want my sampling rate to be 25 kHz. My sampling rate is already
> 195312 Hz which is I think the minimum sampling rate for X310.
>
> What I want is to filter out the frequencies which are at least 25 kHz
> away from my center frequency. For example I don't want to see a
> transmission which is 50 kHz away from my center frequency. Is it possible?
> How does the "bandwidth" parameter in UHD Source Block in GNURadio affect
> the captured IQ data?
>
> Regards,
> Ali
>
> 2018-05-14 12:19 GMT+03:00 Derek Kozel <derek.ko...@ettus.com>:
>
>> Hello Ali,
>>
>> To extend what Marcus has said, here is a link to the UHD manual page
>> about sample rates.
>> http://files.ettus.com/manual/page_general.html#general_sampleratenotes
>>
>> Regards,
>> Derek
>>
>> On Mon, May 14, 2018 at 8:54 AM, Müller, Marcus (CEL) <muel...@kit.edu>
>> wrote:
>>
>>> Hi Ali,
>>>
>>> just like the console will tell you, 25 kS/s is simply impossible with
>>> an X310; instead, the minimum possible rate was used.
>>>
>>> You should probably just configure your X310 to get you e.g. 500 kS/s,
>>> and then resample in digital domain. If you're hesitant to design your
>>> own decimating filter, use the "rational resampler" block and configure
>>> it to decimate by (500/25)=20.
>>>
>>> Best regards,
>>> Marcus
>>>
>>> On Mon, 2018-05-14 at 10:18 +0300, Ali wrote:
>>> > Hi to all,
>>> >
>>> > I am using GNURadio to control an X310. I want to get IQ samples for
>>> only 25 kHz bandwidth.
>>> >
>>> > When I wrote 25 kHz to the bandwidth line in UHD-Source block in
>>> GNURadio, I still see the signals at 50 kHz or 75 kHz away from the center.
>>> My sampling rate is 195312 Hz. When checked in MATLAB, the signals are
>>> there. It looks like I cannot control the bandwidth with GNURadio.
>>> >
>>> > I suspected that there is not any DDC filter for this bandwidth. If it
>>> is so, what is the minimum bandwidth for USRPs? Are the bandwidths that I
>>> can use discrete? I am confused.
>>> >
>>> > Thanks in advance,
>>> > Ali
>>> >
>>> > _______________________________________________
>>> > Discuss-gnuradio mailing list
>>> > discuss-gnura...@gnu.org
>>> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> discuss-gnura...@gnu.org
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>
>>>
>>
>
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