I already tried that, but may be it is a parameter values issue I used : Sample per symbol=4 Filter rolloff factor =350m Prototype filter size 44 Loop bandwidth 62.8m
When the input value is random source (228,229), it works But when the input value is random source (0,256), it doesn't work Best Regards, On Wed, Aug 28, 2024, 9:02 PM Marcus D. Leech <patchvonbr...@gmail.com> wrote: > On 28/08/2024 12:13, ali siddig wrote: > > Dear all, > > I have tried to use the QPAK modulation and demodulation exapmle from > > the tutorial in the link below. I am using two USRPs B205 as > > transmitter and receiver, frequency 910MHz , sampling rate 300k or 1 M > > sps. However, the received signal's constellation after Costas loop > > are not synchronized (points everywhere in the constellation diagram). > > Am I missing something i have to change in the usrp setting or > > synchronization block? > > > > > https://wiki.gnuradio.org/index.php?title=QPSK_Mod_and_Demod#Phase_and_Frequency_Correction > > > > Best regards, > > Ali siddig > > > > _______________________________________________ > > USRP-users mailing list -- usrp-users@lists.ettus.com > > To unsubscribe send an email to usrp-users-le...@lists.ettus.com > This is more-properly a question for the discuss-gnuradio mailing list, > not here. > > My guess is that you will also require some kind of FLL to track the > inevitable frequency differences between TX and RX. But > that's just a slightly-educated guess. > > > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com >
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