90 lines
3.7 KiB
Python
Executable File
90 lines
3.7 KiB
Python
Executable File
#!/usr/bin/env python
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#
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# Copyright 2005,2006,2007 Free Software Foundation, Inc.
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#
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# cqpsk.py (C) Copyright 2009, KA1RBI
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#
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# This file is part of GNU Radio
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#
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# GNU Radio is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# any later version.
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#
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# GNU Radio is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with GNU Radio; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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import sys
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import math
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from gnuradio import gr, gru, audio, eng_notation, blks2, optfir, fsk4
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from gnuradio.eng_option import eng_option
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from optparse import OptionParser
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# accepts an input file in complex format
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# applies frequency translation, resampling (interpolation/decimation)
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# resampled result is CQPSK demodulated then decoded via fsk4.apco25_f()
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class my_top_block(gr.top_block):
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def __init__(self):
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gr.top_block.__init__(self)
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parser = OptionParser(option_class=eng_option)
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parser.add_option("-c", "--calibration", type="int", default=0, help="freq offset")
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parser.add_option("-i", "--input-file", type="string", default="in.dat", help="specify the input file")
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parser.add_option("-l", "--log", action="store_true", default=False, help="dump debug .dat files")
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parser.add_option("-L", "--low-pass", type="eng_float", default=15e3, help="low pass cut-off", metavar="Hz")
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parser.add_option("-o", "--output-file", type="string", default="out.dat", help="specify the output file")
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parser.add_option("-s", "--sample-rate", type="int", default=250000, help="input sample rate")
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parser.add_option("-v", "--verbose", action="store_true", default=False, help="dump demodulation data")
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(options, args) = parser.parse_args()
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sample_rate = options.sample_rate
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symbol_rate = 4800
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sps = 10
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# output rate will be 48,000
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ntaps = 11 * sps
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new_sample_rate = symbol_rate * sps
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lcm = gru.lcm(sample_rate, new_sample_rate)
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interp = lcm // sample_rate
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decim = lcm // new_sample_rate
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channel_taps = gr.firdes.low_pass(1.0, sample_rate, options.low_pass, options.low_pass * 0.1, gr.firdes.WIN_HANN)
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FILTER = gr.freq_xlating_fir_filter_ccf(1, channel_taps, options.calibration, sample_rate)
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sys.stderr.write("interp: %d decim: %d\n" %(interp, decim))
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bpf_taps = gr.firdes.low_pass(1.0, sample_rate * interp, options.low_pass, options.low_pass * 0.1, gr.firdes.WIN_HANN)
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INTERPOLATOR = gr.interp_fir_filter_ccf (int(interp), bpf_taps)
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DECIMATOR = blks2.rational_resampler_ccf(1, int(decim))
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IN = gr.file_source(gr.sizeof_gr_complex, options.input_file)
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DEMOD = blks2.cqpsk_demod( samples_per_symbol = sps,
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excess_bw=0.35,
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costas_alpha=0.03,
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gain_mu=0.05,
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mu=0.05,
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omega_relative_limit=0.05,
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log=options.log,
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verbose=options.verbose)
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msgq = gr.msg_queue()
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DECODER = fsk4.apco25_f(msgq,0)
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self.connect(IN, FILTER, INTERPOLATOR, DECIMATOR, DEMOD, DECODER)
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if __name__ == "__main__":
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try:
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my_top_block().run()
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except KeyboardInterrupt:
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tb.stop()
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