75 lines
2.8 KiB
Python
75 lines
2.8 KiB
Python
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#!/usr/bin/env python
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# a small script to transmit simulated GPS samples via UHD
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# (C) 2015 by Harald Welte <laforge@gnumonks.org>
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# Licensed under the MIT License (see LICENSE)
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from gnuradio import blocks
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from gnuradio import eng_notation
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from gnuradio import gr
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from gnuradio import uhd
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from gnuradio.eng_option import eng_option
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from gnuradio.filter import firdes
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from optparse import OptionParser
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import time
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class top_block(gr.top_block):
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def __init__(self, options):
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gr.top_block.__init__(self, "GPS-SDR-SIM")
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##################################################
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# Blocks
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##################################################
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self.uhd_usrp_sink = uhd.usrp_sink(
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",".join(("", "")),
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uhd.stream_args(
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cpu_format="fc32",
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channels=range(1),
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),
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)
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self.uhd_usrp_sink.set_samp_rate(options.sample_rate)
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self.uhd_usrp_sink.set_center_freq(options.frequency, 0)
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self.uhd_usrp_sink.set_gain(options.gain, 0)
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# a file source for the file generated by the gps-sdr-sim
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self.blocks_file_source = blocks.file_source(gr.sizeof_char*1, options.filename, True)
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# convert from signed bytes to short
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self.blocks_char_to_short = blocks.char_to_short(1)
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# convert from interleaved short to complex values
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self.blocks_interleaved_short_to_complex = blocks.interleaved_short_to_complex(False, False)
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# establish the connections
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self.connect((self.blocks_file_source, 0), (self.blocks_char_to_short, 0))
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self.connect((self.blocks_char_to_short, 0), (self.blocks_interleaved_short_to_complex, 0))
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self.connect((self.blocks_interleaved_short_to_complex, 0), (self.uhd_usrp_sink, 0))
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def get_options():
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parser = OptionParser(option_class=eng_option)
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parser.add_option("-x", "--gain", type="eng_float", default=0,
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help="set transmitter gain [default=0]")
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parser.add_option("-f", "--frequency", type="eng_float", default=1575420000,
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help="set transmit frequency [default=1575420000]")
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# On USRP2, the sample rate should lead to an even decimator
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# based on the 100 MHz clock. At 2.5 MHz, we end up with 40
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parser.add_option("-s", "--sample-rate", type="eng_float", default=2500000,
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help="set sample rate [default=2500000]")
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parser.add_option("-t", "--filename", type="string", default="gpssim.bin",
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help="set output file name [default=gpssim.bin]")
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(options, args) = parser.parse_args()
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if len(args) != 0:
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parser.print_help()
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raise SystemExit, 1
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return (options)
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if __name__ == '__main__':
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(options) = get_options()
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tb = top_block(options)
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tb.start()
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raw_input('Press Enter to quit: ')
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tb.stop()
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tb.wait()
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