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#!/usr/bin/env python
# import the GNU Radio code
import os
from gnuradio import gr, blks
import gsm
from gnuradio.blksimpl import gmsk
gsm_rate = 1625000.0 / 6.0 # GSM samples / symbol
# most useful file Robert has
#file_name = os.environ.get("GSMSPROOT") + "/resources/data/GSMSP_20070218_robert_dbsrx_941MHz_112.cfile"
#file_name = os.environ.get("GSMSPROOT") + "/resources/data/GSMSP_20070204_robert_dbsrx_953.6MHz_64.cfile"
file_name = "signal.data"
#decimation = 64 # the decimation Robert used
#decimation = 112 # the decimation Robert used
decimation = 118 # the decimation Robert used
sps = 64e6 / decimation # samples / second with this decimation
filter_cutoff = 150e3 # bandpass filter between +/- 150kHz
filter_t_width = 50e3 # width of filter transition
offset = 0 # Robert didn't need an offset
# create a GNURadio Flow Graph
fg = gr.flow_graph()
# create a file source from Robert's file
source = gr.file_source(gr.sizeof_gr_complex, file_name)
# create a filter with the above constants
filter_taps = gr.firdes.low_pass(1.0, sps, filter_cutoff,
filter_t_width, gr.firdes.WIN_HAMMING)
filter = gr.freq_xlating_fir_filter_ccf(1, filter_taps, offset, sps)
# create the GMSK demod object
gd = gmsk.gmsk_demod(fg, sps / gsm_rate, gain_mu = 0.01,
omega_relative_limit = 0.005)
#diff = gr.diff_decoder_bb (2)
gsm = gsm.run_bb ()
#sqr = gr_example_b.square_bb ()
# create the vector sink
#sink = gr.vector_sink_b()
# connect all the blocks together
fg.connect(source, filter, gd, gsm)
# process the file
fg.run()
# dump the data
#print sink.data()
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