diff options
| author | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-09-14 03:07:01 +0000 |
|---|---|---|
| committer | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-09-14 03:07:01 +0000 |
| commit | aa0555b49ca61be638bc57b8d823d870aeb3edbb (patch) | |
| tree | ecd919767a62700f7e2431b62223018df95e2902 /gr-pager/src/flex_demod.py | |
| parent | 86f5c92427b3f4bb30536d76cf63c3fca388fb2f (diff) | |
Added gr-pager component to trunk by merging from r3474:r3537 in
branch developer/jcorgan/pager. Currently implements most of the FLEX
pager protocol demodulation, but doesn't yet decode individual pages.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3538 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'gr-pager/src/flex_demod.py')
| -rw-r--r-- | gr-pager/src/flex_demod.py | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/gr-pager/src/flex_demod.py b/gr-pager/src/flex_demod.py new file mode 100644 index 0000000000..8326c9fa5d --- /dev/null +++ b/gr-pager/src/flex_demod.py @@ -0,0 +1,57 @@ +# +# Copyright 2006 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2, or (at your option) +# any later version. +# +# GNU Radio is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with GNU Radio; see the file COPYING. If not, write to +# the Free Software Foundation, Inc., 51 Franklin Street, +# Boston, MA 02110-1301, USA. +# + +from gnuradio import gr, optfir +from math import pi +import pager_swig + +class flex_demod(gr.hier_block): + """ + FLEX protocol demodulation block. + + This block demodulates a band-limited, complex down-converted baseband + channel into FLEX protocol frames. + + Flow graph (so far): + + QUAD - Quadrature demodulator converts FSK to baseband amplitudes + LPF - Low pass filter to remove noise prior to slicer + SLICER - Converts input to one of four symbols (0, 1, 2, 3) + DEFRAMER - Syncronizes symbol stream and outputs FLEX codewords + --- + + @param fg: flowgraph + @param channel_rate: incoming sample rate of the baseband channel + @type sample_rate: integer + """ + + def __init__(self, fg, channel_rate): + k = channel_rate/(2*pi*4800) # 4800 Hz max deviation + QUAD = gr.quadrature_demod_cf(k) + + taps = optfir.low_pass(1.0, channel_rate, 3200, 6400, 0.1, 60) + LPF = gr.fir_filter_fff(1, taps) + SLICER = pager_swig.slicer_fb(.001, .00001) # Attack, decay + DEFRAMER = pager_swig.flex_deframer(channel_rate) + + fg.connect(QUAD, LPF, SLICER, DEFRAMER) + + gr.hier_block.__init__(self, fg, QUAD, DEFRAMER) |