As indicated by Dan, what you observe is the transmit side pulse shaping; the PSK Mod block incorporates both the constellation mapper as well as pulse shaping.
But, by the way, we've removed that PSK Mod block, I think, from the upcoming release; seems our tutorials haven't caught up so far. So, follow Cinaed's advice from his reply to your original email :) Best regards, Marcus On Fri, 2018-11-02 at 08:41 -0400, Mercado, Alejandra wrote: > Dear Dan, > > Thanks for the response, but I am not including a receiver in this GRC. I was > just creating a QPSK and looking at the constellation. When you use the > Chunks to Symbols" block and plot it, it comes out cleanly, but when you use > the PSK Mod there are samples in the origin. > > Just wondering which is the cause. > > On Thu, Nov 1, 2018 at 9:56 PM Dan CaJacob <dan.caja...@gmail.com> wrote: > > I think this happens when you don't have matched filters? > > > > On Thu, Nov 1, 2018 at 10:45 AM Mercado, Alejandra <merc...@ece.umd.edu> > > wrote: > > > Dear GnuRadio folks, > > > > > > I have a questions about the "PSK Mod" block of GnuRadio. I am following > > > the tutorial found here: > > > https://wiki.gnuradio.org/index.php/Guided_Tutorial_Hardware_Considerations > > > (the grc is attached) > > > > > > I followed the instructions to see the output of PSK Mod for 4 > > > constellation points. To my surprise, the constellation graph shows > > > points that are ambiguously between quadrants (see the screenshot). > > > > > > What causes this? Is it the PSK Mod block that creates output points that > > > do not correspond to one of the four points? Or is it the QT GUI that is > > > not displaying the output correctly? Or both? > > > > > > Thanks and regards > > > _______________________________________________ > > > Discuss-gnuradio mailing list > > > Discuss-gnuradio@gnu.org > > > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > -- > > Very Respectfully, > > > > Dan CaJacob > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
