Re: [Discuss-gnuradio] USRP Digital Modulation - Loopeback Constellation

[Luis Felipe Albarracin Sanchez]

Hello Marcus,

Thanks for the response,

I am not using an attenuator, because i font have one , i am only with my cable, but i have meassured the Power before connecting to the RX in my USRP, so it wont be bigger than the threshold of the USRP.

Thanks for the info, is there any guide where i can look all of the blocks for Sync, phase tracking and shape filtering  implemented in a loopback for 16QAM and other digital modulations (Flowgraphs examples)?

Thanks a lot for the help.

On Thu, Jun 14, 2018 at 12:00 PM, Müller, Marcus (CEL) <address@hidden> wrote:

Hi Luis,

I hope you're using an attenuator with a cable or antennas in your
feedback, not to risk damaging your receiver!

What you need to do to get a similar constellation is the whole dance
that is taught in your average digital communication basics lecture:

Synchronization in time, and phase (and theoretically frequency, but
when it's really only a loopback, that's not an issue, since they will
be identical), an equalizer if your channel leads to ISI, and
potentially phase tracking, as well as usually some sort of pulse
shaping filter etc.

Best regards,
Marcus

On Thu, 2018-06-14 at 10:59 +0200, Luis Felipe Albarracin Sanchez
wrote:
> Hello all,
>
> I am trying to do a Loopback with an USRP B210, ad i have the following flowgraph:
>
>
>
>
>
> For mi test i need to obtain a similar constellation once i received the signal, but i am getting:
>
>
>
>
> My question is, are there any blocks missing or what else i need to do, to obtain a similar constellation in the Rx side?
>
> Once again, thank you very much.
>
> Kind regards.
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

--

Eng. Luis Felipe Albarracin
PMP
CCNA/CCDA/CCNP/CCDP/CCIP
ITIL v3 Foundation
Msc. Telematics / MBA
"Die Grenzen meiner Sprache bedeuten die Grenzen meiner Welt"