Re: QPSK phase noise


#1

u r welcomed!

e.g. dst = gr.vector_sink_c ()
result = dst.data()
dump that result into a file using dump(result, the
handle of that file).
Thanks!

Bill


From: yufeng wang removed_email_address@domain.invalid
To: Bill S. removed_email_address@domain.invalid
Sent: Friday, April 10, 2009 6:17:49 PM
Subject: Re: [Discuss-gnuradio] QPSK phase noise

Thanks, Bill. I think we may also use the plot codes under the file
gr-utils, where plot_const.py and usrp_fft.py can be found. I have
used the usrp_fft.py to display the output signal, and I’m trying to
install scipy to enable the plot_const.py, etc. I also wanna load the
data using Matlab, I wonder how can you output the data to a sink
file? Thanks!

On Fri, Apr 10, 2009 at 4:46 PM, Bill S.
removed_email_address@domain.invalid wrote:

From: yufeng wang removed_email_address@domain.invalid
I’m using benchmark.py to transmit and receive BPSK signals. I can use

wrong in the mpsk_receiver block. I am checking it. Thanks!
Johnathan, you were right with the distortion issue at the TX, I am now
http://img149.imageshack.us/img149/4583/screenshot4h.png ) I think we

./benchmark_rx.py -m dbpsk --verbose -S 4 -r 200k --excess-bw=0.35 -f
purple: I

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Yufeng


Best wishes,

Yufeng


#2

For the plots I am just using the gr_plot_const.py FILENAME.dat where
FILENAME.dat comes from connnecting the block of interest using
self.connect(self.receiver, gr.file_sink(gr.sizeof_gr_complex,
“FILENAME.dat”))

For the costas loop and BPSK constellations I was using a custom script
in
python that reads the output of a text file with the relevant
information
after enabling the DEBUG line of the mpsk_receiver.cpp:

cl: phase_error: 0.000000 phase: 0.000000 freq: 0.000000 sample:
0.000000+j0.000000 constellation: 0.000000+j-1.000000
cl: phase_error: 0.000000 phase: 0.000000 freq: 0.000000 sample:
0.000000+j0.000000 constellation: 0.000000+j-1.000000
cl: phase_error: 0.000000 phase: 0.000000 freq: 0.000000 sample:
0.000000+j0.000000 constellation: 0.000000+j-1.000000
cl: phase_error: 0.000000 phase: 0.000000 freq: 0.000000 sample:
0.000000+j0.000000 constellation: 0.000000+j-1.000000

the script is http://www.nabble.com/file/p23038239/plot_const.py
plot_const.py for the const and
http://www.nabble.com/file/p23038239/plot_error.py plot_error.py for
the
costas error.

Bill, have you already found anything wrong in the gr_mpsk_receiver.cc
file?
I remember I could get much better constellation figures long time ago.

Cheers,
Paco.


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