Dear Rafik, I think we're approaching this from the wrong side: I don't think that I should be explaining why you get a good BER and SNR estimate, it is you who should explain why you're expecting something different, and then we can discuss! I'm not quite sure what I could be explaining at this point :)
Best regards, Marcus On 07/04/2017 11:20 AM, Rafik ZITOUNI wrote: > Thank you Marcus for your answer ! > > My BER and SNR are calculated and obtained using MPSK SNR Estimator > Probe and Error Rate blocks. I obtained two points, which rotate in > the qt gui constellation sink despite the BER and SNR have been > obtained as expected. Could you give me an explanation how it was > possible to obtain a good snr and ber with a wrong constellation with > good SNR and BER? > > I found the presentation of Tom Rondeau useful, since he explained > the function of the costas loop > block. > https://static.squarespace.com/static/543ae9afe4b0c3b808d72acd/543aee1fe4b09162d08633fc/543aee1fe4b09162d0863402/1392309732018/mpsk.pdf > <https://static.squarespace.com/static/543ae9afe4b0c3b808d72acd/543aee1fe4b09162d08633fc/543aee1fe4b09162d0863402/1392309732018/mpsk.pdf> > > > This morning I add a Costas loop after a Polyphase Clock > Syncronisation block, and it s going well. You find attached a > screenshot of my constellation for a DBPSK of > my receiver/transmitter. I propose to add a grc to gnuradio/gr-digital > for MPSK since grc is more easy to understand than python source code. > > > Now I am trying to send and receive data files such as videos or > images (bmp). Do you have an example with a file exchange implemented > in .py or grc? > > Best, > > > 2017-07-04 9:44 GMT+02:00 Marcus Müller <marcus.muel...@ettus.com > <mailto:marcus.muel...@ettus.com>>: > > Hi Rafik! > > So, what's wrong with the BER and the SNR estimate? > > Best regards, > > Marcus > > > On 07/03/2017 11:29 PM, Rafik ZITOUNI wrote: >> Dear all, >> >> I translate the >> /gr-digital/examples/narrowband/digital_bert_tx.py and the >> /gr-digital/examples/narrowband/digital_bert_rx.py python source >> codes to GRC flow graphs. The objective is to get more graphical >> possibilities with a GRC. My flow graph gives a fine result of >> BER and SNR for DBPSK modulation. >> The problem is with the rotating points of my constellation. I >> think that the rotation of my view comes from a lack of frequency >> synchronization, but why I obtained a correct BER and SNR? >> >> You find attached to this message a constellation view obtained >> by my flow graph. >> >> Please could you explain me this result or give an advice to >> improve the obtained result? >> >> Regards, >> >> >> -- >> **<http://www.ece.fr/>Rafik >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> > _______________________________________________ Discuss-gnuradio > mailing list Discuss-gnuradio@gnu.org > <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > <https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> > > -- > **<http://www.ece.fr/>Rafik
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