On 28/08/2024 13:35, ali siddig wrote:
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,
And, again, this is more properly a question for the discuss-gnuradio
mailing list. The UHD library doesn't
provide any DSP functions, per se. So any gnuradio flow-graph
questions should be on the discuss-gnuradio mailing list.
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
>
> _______________________________________________
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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.
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