Forum: GNU Radio atsc

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unknown (Guest)
on 2009-01-23 21:19
(Received via mailing list)
I need a little help with atsc demodulation procedure, I used the
procedure
found in the README


1) Verify signal, adjust antenna and find best gain setting using
usrp_fft.py,
station frequency from the fcc video database, and decimation of 10.

2) Capture data - adjust gain (-g) frequency (-f) and which side
the tvrx is on to fit your local setup:

usrp_rx_cfile.py -s -R B -d 10 -g 65 -f 503e6 atsc_data_6-4m_complex---I
did not
use this command

./usrp2_rx_cfile.py -s -e eth0 -m 00:50:c2:85:30:9c -d 16 -f 519e6 -g 70
-N
250000000 atsc_data_6-4m_complex


You probably still need fast disks to take the data, like a raid-0 set
of
striped sata drives. Make sure there are no or very few Ou overruns.
Saving
the raw usrp data in 'short' form halves the disk space/bus bandwidth
that
the usual complex form uses.

3) Make pipes:

mkfifo /tmp/atsc_pipe_1
mkfifo /tmp/atsc_pipe_2
mkfifo /tmp/atsc_pipe_3
mkfifo /tmp/atsc_pipe_4
mkfifo /tmp/atsc_pipe_5

4) In seperate windows run processes:

./interp_short.py <input rf data at 6.4Msps>
./xlate.py
./fpll.py
./btl-fsd.py
./viterbi-out.py <output mpeg transport stream>

 When I execute step 4, the scripts appear to execute properly.  When I
go to
the /tmp directory I do not see the pipes filling, the sizes remains 0.
When I
stop the execution of the scripts I do not have any data in my output
file.  Am
I missing a step with piping the files.

If I remove the pipes and execute the files sequentially (without any
pipes).
First executing ./interp_short.py  then ./xlate.py a few seconds later
and so
on. I see the files (/tmp/atsc_pipe_(1-3) growing but not
/tmp/atsc_pipe_5.
The 'btl-fsd.py'script is not saving data to /tmp/atsc_pipe_5.

I could use a little insight in executing this process.

Thank You
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