Hi Julian,
Thanks for your reply.
I am basically trying to receive signals of BW 5MHz at two different centre
frequencies (2.475GHz and 2.48GHz) using the two subdevs of the B210.
The master clock rate gets set to 20MHz which makes me assume that the analog
bandwidth for the USRP source is 20 MHz.
With a centre frequency of 2.475GHz, it should cover from 2.465GHz to 2.485GHz.
The main problem I have difficulty understanding is why it works in Case 1 and
why it behaves randomly in Case 2.
Thanks,
Saptarshi
> On 9 Dec 2020, at 15:49, Julian Arnold <jul...@elitecoding.org> wrote:
>
> Saptarshi,
>
> I'm not entirely sure I fully understand what you are doing. You probably
> need to provide some more details.
>
> However, in general, depending on what you master-clock-rate is,
> doing a 5MHz shift in the DSP does not make much sense if your
> sample-rate and your analog bandwidth are only 5 MHz. There is just no signal
> at your 5MHz offset you could possibly shift down to base-band.
>
> Cheers,
> Julian
>
> On 12/9/20 10:41 AM, Saptarshi Hazra via USRP-users wrote:
>> Hi,
>> I am trying to receive on two different centre frequencies (2.475e9 and
>> 2.48e9) using the two receiver chains on B210. Since they are close by, I
>> thought can receive them by setting the “dsp_freq” parameter.
>> Case 1:
>> Subdev: A:A or A:B
>> Nchannel : 1
>> Centre Frequency: 2.475e9
>> Sampling Rate: 5e6
>> BW: 5e6
>> If I use the command port the USRP source block to pass a pmt dictionary:
>> pmt.to_pmt({“lo_freq”:2.475e9, “dsp_freq”: -5e6})
>> I am able to receive radio packets sent by nodes on 2.48e9 Hz
>> Case 2:
>> Subdev: A:A A:B
>> Nchannel : 2
>> Sampling Rate: 5e6
>> Centre Frequency 1: 2.475e9
>> Centre Frequency 2: 2.475e9
>> BW: 5e6
>> I use the pmt dictionary:
>> pmt.to_pmt({“chan”:0, “lo_freq”:2.475e9, “dsp_freq”: -5e6})
>> When I do this sometimes I receive data from nodes transmitting on 2.48e9Hz.
>> and sometimes on 2.475Hz. The behaviour becomes entirely random.
>> I would really appreciate any help in figuring out how to receive
>> simultaneously on these two centre frequencies.
>> Thanks,
>> Saptarshi
>> _______________________________________________
>> USRP-users mailing list
>> USRP-users@lists.ettus.com
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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