Re: [Discuss-gnuradio] RDS reception

[Philip Balister]

On 02/24/2012 02:45 PM, Rafael Diniz wrote:
> It would be nice, but it could be fixed up and converted to cmake in the
> current svn repo also...

But most of us have forgotten how to use subversion :)

Philip

> 
> 
> 
>> The CGRAN RDS code seems abandoned, I'm thinking about cloning it to
>> github so it can be converted to UHD and Cmake and fixed up.
>>
>> On Fri, Feb 24, 2012 at 1:31 PM,  <address@hidden> wrote:
>>> I don't know about having it inside the main codebase, but converting it
>>> to
>>> use the CMake build system would be good, since it didn't really
>>> understand
>>> how to place its python files into a filesystem that uses
>>> /usr/local/lib64--so I had to move them manually.
>>>
>>> -Marcus
>>>
>>>
>>>
>>> On Fri, 24 Feb 2012 10:23:48 -0800, Rafael Diniz wrote:
>>>
>>> It would be great to have the rds code inside the gnuradio tree instead
>>> of
>>> in a separate cgran project!
>>> ; )
>>>
>>> I don't know why, but when I tried the cgran rds code, the grc example
>>> worked much better then the python one.
>>>
>>> Best regards,
>>> Rafael Diniz
>>>
>>>
>>>
>>> Actually, I'm using the blks2 WBFM block, which I believe is a PLL
>>> demodulator.
>>>
>>> Both of my "test" stations are actually roughly 100km
>>> away from me, broadcasting from a high point in the Ottawa Valley.
>>>
>>> One
>>> station comes in about 10dB stronger than the other, although both have
>>> an ERP of about 100kW, and both are located on the same transmit tower.
>>>
>>>
>>> I'll send you my 'stuff' once I'm more comfortable with it. The audio
>>> quality is actually reasonably good, so I think the FM demodulator
>>> portion is just fine.
>>>
>>> -Marcus
>>>
>>> On Fri, 24 Feb 2012 11:12:28 -0500,
>>> Andrew Davis wrote:
>>>
>>> I think the problems with SNR is with the FM
>>>
>>> Demod, my car stereo can
>>>
>>> get RDS as the station fades 40 miles away,
>>>
>>> but with my USRP has
>>>
>>> trouble picking up the stereo pilot from a 50kw
>>>
>>> station one mile away
>>>
>>> ( -10dBm ). FM demod is hard for software ( I
>>>
>>> think GNUradio just uses
>>>
>>> a zero-crossing detector ).
>>>
>>> Do you have
>>>
>>> the code, I would love to test it.
>>>
>>> On Thu, Feb 23, 2012 at 11:33
>>>
>>> PM, Marcus D. Leech wrote:
>>>
>>> I managed to get gr-rds built tonight, and
>>>
>>> was able to test it planted inside my FM receiver. Even for a local
>>> station, there are *lots* of errors, and more distant stations get even
>>> more. I'm going to play around a bit with filter bandwidths, etc, to see
>>> if I can improve it. Looking at the modulation technique, it's no big
>>> surprise--they use a bi-phase baseband coding (basically like
>>> differential Manchester), that drives a DSB-SC modulator with a carrier
>>> at 57kHz. But that signal is generally about 20dB below the other audio
>>> sub-channels on the FM demodulator output. So the SNR is generally
>>> *terrible*. I'm rather surprised, after looking at it, that anyone
>>> bother deploying RDS. It seems utterly crappy. It's generally broadcast
>>> with fairly-low SNR, and there's no FEC built in, only CRC. I re-jigged
>>> the XML for the demodulator part so you can reset the demodulator state
>>> machine from within a GRC flow-graph (there was a reset() method on the
>>> demod, but it wasn't exposed within the XML framework for GRC). Also, I
>>> may re-jig the decoder portion--it currently injects decoded frames into
>>> a message queue and to stdout. Might be useful to do other things with
>>> those messages. Like is there a simple way to have a message dequeuer
>>> within a GRC flow-graph so that one could stuff messages into a
>>> variable? -- Principal Investigator Shirleys Bay Radio Astronomy
>>> Consortium http://www.sbrac.org [1]
>>> _______________________________________________ Discuss-gnuradio mailing
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>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio [3]
>>>
>>>
>>>
>>>
>>> Links:
>>> ------
>>> [1] http://www.sbrac.org
>>> [2]
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