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[Discuss-gnuradio] RDS decoding
From: |
jmfriedt |
Subject: |
[Discuss-gnuradio] RDS decoding |
Date: |
Thu, 9 Mar 2017 20:42:40 +0100 |
As briefly mentioned at FOSDEM, I have been investigating RDS since last
christmas, trying to
tackle each issue step by step from LO synchronization for BPSK demodulation,
bit decoding,
sentence synchronization, station name and free text extraction, error
correcting code implementation
and finally transferred time analysis. My objective was of course not to
compete with gr_rds, used
as a reference, but to acquire a detailed understanding of each step. Since I
protoype with GNU/Octave,
I wanted to convert most digital signal processing from LFSR to linear algebra
(matrix). I think I
pretty much understand now the whole process, despite designing the error
correcting code being still
beyond my capability. An internal lab presentation on the topic is now
available at
http://jmfriedt.free.fr/slides_rds.pdf
and for the French speaking audience, accompanying article (in French at the
moment, will be translated
ASAP to English, as soon as I have completed RDS v.s GPS time comparisons) at
http://jmfriedt.free.fr/lm_rds.pdf
I am well aware of Tom Rondeau's sponsoring Polyphase clock recovery, but at
the moment I could
only figure out how to use MM-Clock recovery and MPSK, which worked quite well
for my purpose.
Any feedback welcome,
JM
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000
Besancon, France