Hi John, My question is about USRP B210, can we use it to set RF bw as 50MHz and then sample using 2MHz sampling rate?
Thanks Wahhab On Dec 29, 2017 11:54 AM, "John Shields" <[email protected]> wrote: > Hi Wahhab, > As Kyeong had already pointed out, in this > configuration, the bw limiting factor is the daughtercard. For the SBX the > bandwidth is 40 MHz. There are other Ettus products covering the same > frequency range which have wider bandwidth (80,120,160 MHz) but they seem > to only plug into the X-series of products. > https://www.ettus.com/product/category/Daughterboards > > Kind Regards, > > John > > *From:* Wahhab Albazrqaoe <[email protected]> > *Sent:* Saturday, December 30, 2017 4:39 AM > *To:* Kyeong Su Shin <[email protected]> > *Cc:* John Shields <[email protected]> ; [email protected] > *Subject:* Re: [USRP-users] Enable aliasing using USRP > > Dear Kyeong, > Thank you for the reply. > How about using USRP B210, do you think we can get aliasing by setting the > RF bw=50MHz and sample at 2MHz? > > Thank you. > Wahhab > > On Dec 29, 2017 12:19 AM, "Kyeong Su Shin" <[email protected]> wrote: > >> Hello Wahhab, >> >> If I recall correctly, you can *not* change the bandwidth of SBX (always >> 40MHz), and the sampling rate of the USRP2 (always 100MS/s). What you are >> actually setting by setting --rate 2e6 is the decimation ratio. The signals >> will be always sampled at 100MS/s, and then decimated by the decimator >> within the FPGA. >> >> It is still possible to cause aliasing - one way is to just sample at a >> fast sampling rate and then decimate by yourself. An other way would be >> tinkering the digital filters used by the decimator, but I am not sure if >> there are good APIs to do that. I am pretty sure that rx_samples_to_file is >> not suitable for the task, though (correct me if I am wrong). That is just >> an example program. >> >> Regards, >> Kyeong Su Shin >> >> On Thu, Dec 28, 2017 at 6:29 PM, Wahhab Albazrqaoe via USRP-users < >> [email protected]> wrote: >> >>> Hi John, >>> Thank you for your reply. >>> We would like to create aliasing. This means that we should set ADC to >>> sample at speed less than Nyquist rate. >>> In our setting, we target RF front end to be 50MHz and ADC speed is 2MHz. >>> The question is how to do it? We use some commands (as shown in my >>> previous email) but seems not working as expected, i.e. RF front end >>> bandwidth is still 2MHz. >>> >>> Best, >>> >>> On Thu, Dec 28, 2017 at 9:24 PM, John Shields <[email protected]> >>> wrote: >>> >>>> Hi Wahhab, >>>> This is a fairly basic issue – the ‘bandwidth’ (if >>>> that is really what you are really meaning) is related to the sample_rate >>>> by The Nyquist Frequency >>>> >>>> https://en.wikipedia.org/wiki/ >>>> Nyquist_frequency >>>> >>>> Kind Regards, >>>> >>>> John >>>> >>>> *From:* Wahhab Albazrqaoe via USRP-users <[email protected]> >>>> *Sent:* Friday, December 29, 2017 3:04 PM >>>> *To:* [email protected] >>>> *Subject:* [USRP-users] Enable aliasing using USRP >>>> >>>> Dear All, >>>> I have question about how to create aliasing using USRP. >>>> Basically, I have USRP2 with SBX (with recent installations of GnuRadio >>>> and UHD). >>>> I would like to set the bandwidth of the RF front end to 50 MHz, and >>>> use 2MHz of sampling rate (ADC speed). >>>> I am using the following command: >>>> sudo ./rx_samples_to_file --args addr=192.168.10.2 >>>> master_clock_rate=50e6 --freq=2460e6 --bw=50e6 --rate 2e6 --gain=50 >>>> --wirefmt sc8 --nsamps 0 >>>> >>>> >>>> >>>> Problem: it seems to me that the system (GnuRadio/USRP) observes only >>>> 2MHz of RF front end bandwdith. How do I know this? Ans: I compare such >>>> settings with the following settings: >>>> sudo ./rx_samples_to_file --args addr=192.168.10.2 >>>> master_clock_rate=50e6 --freq=2460e6 --bw=50e6 --rate 50e6 --gain=50 >>>> --wirefmt sc8 --nsamps 0 >>>> >>>> The later setting seems to be actual 50 MHz of Rf front end. >>>> >>>> Any comments and advices on how to create aliasing using USRP are >>>> appreciate. >>>> >>>> Best, >>>> Wahhab >>>> >>>> >>>> ------------------------------ >>>> _______________________________________________ >>>> USRP-users mailing list >>>> [email protected] >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>>> >>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >>>> Virus-free. >>>> www.avast.com >>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >>>> >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> [email protected] >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >
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