Thank you Jeff.. Are these filters in software? Or fpga? Is there any function that we play with to get aliasing? i.e. how to disable such filters?
Thank you Wahhab The B2XX bandwidth can be adjusted, but that is in addition to other filters designed to remove aliases based on the sample rate. On Dec 29, 2017 11:57 AM, "Wahhab Albazrqaoe" <albaz...@msu.edu> wrote: > 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" <john.shie...@xtra.co.nz> 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 <albaz...@msu.edu> >> *Sent:* Saturday, December 30, 2017 4:39 AM >> *To:* Kyeong Su Shin <kss...@uw.edu> >> *Cc:* John Shields <john.shie...@xtra.co.nz> ; usrp-users@lists.ettus.com >> *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" <kss...@uw.edu> 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 < >>> usrp-users@lists.ettus.com> 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 <john.shie...@xtra.co.nz> >>>> 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 <usrp-users@lists.ettus.com> >>>>> *Sent:* Friday, December 29, 2017 3:04 PM >>>>> *To:* usrp-users@lists.ettus.com >>>>> *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 >>>>> USRP-users@lists.ettus.com >>>>> 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 >>>> USRP-users@lists.ettus.com >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>>> >>> >>
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