Hi Bernardo, I'm pretty sure the filter code hasn't changed too much since 3.2.2. However, I'm surprised it worked before: Your FM demodulator requires a pretty steep filter (the transition width is less than 0.005 normalised to the sampling frequency). I only had a quick peek, but since your decimation in the FM demod is 1, you could use a frequency demod instead and couple it with your own (custom) filter. The gr_remez code is a bit unstable in this respect. You normally have to fiddle around with the parameters until you get a good filter, and the FM demod block doesn't give you enough knobs.
MB On Mon, Feb 28, 2011 at 11:25:54AM -0300, Bernardo Guadagnin Gonçalves wrote: > Hello, > > > Until last week I was using the Gnu Radio 3.2.2 (which is ready for use in > ubuntu), then I decided to try the latest version (v3.3.1git-147-g5a23954a). > The flowgraph was working perfectly. It's for "in" GRC simulation only. I know > it's very simple and the 38kHz recovery (at the receiver) is not the > recommended way. > > > Flowgraph: http://dl.dropbox.com/u/8898915/FMstereotxrx2.grc > > .Wav for simulation: http://dl.dropbox.com/u/8898915/sine4k.wav > > > The messages that are now shown are: > > > Showing: "/home/mula/Dropbox/Public/FMstereotxrx2.grc" > > > Generating: "/home/mula/Dropbox/Public/top_block.py" > > > Executing: "/home/mula/Dropbox/Public/top_block.py" > > > gr_remez: insufficient extremals -- cannot continue > > Traceback (most recent call last): > > File "/home/mula/Dropbox/Public/top_block.py", line 361, in <module> > > tb = top_block() > > File "/home/mula/Dropbox/Public/top_block.py", line 193, in __init__ > > tau=tau, > > File > "/usr/local/lib/python2.6/dist-packages/gnuradio/blks2impl/fm_demod.py", > line 65, in __init__ > > 60) # Stopband attenuation > > File "/usr/local/lib/python2.6/dist-packages/gnuradio/optfir.py", line 53, > in > low_pass > > taps = gr.remez (n + nextra_taps, fo, ao, w, "bandpass") > > File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/ > gnuradio_swig_py_general.py", line 432, in remez > > return _gnuradio_swig_py_general.remez(*args, **kwargs) > > RuntimeError: gr_remez: insufficient extremals -- cannot continue > > > >>> Done > > > Thanks! > > > Regards, > Bernardo > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- Karlsruhe Institute of Technology (KIT) Communications Engineering Lab (CEL) Dipl.-Ing. Martin Braun Research Associate Kaiserstraße 12 Building 05.01 76131 Karlsruhe Phone: +49 721 608-43790 Fax: +49 721 608-46071 www.cel.kit.edu KIT -- University of the State of Baden-Württemberg and National Laboratory of the Helmholtz Association
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