--- /dev/null
+#!/usr/bin/env python
+#
+# Copyright 2006,2007 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 3, 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, gru, usrp, optfir, audio, eng_notation, blks2
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+import sys
+
+"""
+This example application demonstrates receiving and demodulating
+different types of signals using the USRP.
+
+A receive chain is built up of the following signal processing
+blocks:
+
+USRP - Daughter board source generating complex baseband signal.
+CHAN - Low pass filter to select channel bandwidth
+RFSQL - RF squelch zeroing output when input power below threshold
+AGC - Automatic gain control leveling signal at [-1.0, +1.0]
+DEMOD - Demodulation block appropriate to selected signal type.
+ This converts the complex baseband to real audio frequencies,
+ and applies an appropriate low pass decimating filter.
+CTCSS - Optional tone squelch zeroing output when tone is not present.
+RSAMP - Resampler block to convert audio sample rate to user specified
+ sound card output rate.
+AUDIO - Audio sink for playing final output to speakers.
+
+The following are required command line parameters:
+
+-f FREQ USRP receive frequency
+-m MOD Modulation type, select from AM, FM, or WFM
+
+The following are optional command line parameters:
+
+-R SUBDEV Daughter board specification, defaults to first found
+-c FREQ Calibration offset. Gets added to receive frequency.
+ Defaults to 0.0 Hz.
+-g GAIN Daughterboard gain setting. Defaults to mid-range.
+-o RATE Sound card output rate. Defaults to 32000. Useful if
+ your sound card only accepts particular sample rates.
+-r RFSQL RF squelch in db. Defaults to -50.0.
+-p FREQ CTCSS frequency. Opens squelch when tone is present.
+
+Once the program is running, ctrl-break (Ctrl-C) stops operation.
+
+Please see fm_demod.py and am_demod.py for details of the demodulation
+blocks.
+"""
+
+# (usrp_decim, channel_decim, audio_decim, channel_pass, channel_stop, demod)
+demod_params = {
+ 'AM' : (250, 16, 1, 5000, 8000, blks2.demod_10k0a3e_cf),
+ 'FM' : (250, 8, 4, 8000, 9000, blks2.demod_20k0f3e_cf),
+ 'WFM' : (250, 1, 8, 90000, 100000, blks2.demod_200kf3e_cf)
+ }
+
+class usrp_src(gr.hier_block2):
+ """
+ Create a USRP source object supplying complex floats.
+
+ Selects user supplied subdevice or chooses first available one.
+
+ Calibration value is the offset from the tuned frequency to
+ the actual frequency.
+ """
+ def __init__(self, subdev_spec, decim, gain=None, calibration=0.0):
+ gr.hier_block2.__init__(self, "usrp_src",
+ gr.io_signature(0, 0, 0), # Input signature
+ gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+ self._decim = decim
+ self._src = usrp.source_c()
+ if subdev_spec is None:
+ subdev_spec = usrp.pick_rx_subdevice(self._src)
+ self._subdev = usrp.selected_subdev(self._src, subdev_spec)
+ self._src.set_mux(usrp.determine_rx_mux_value(self._src, subdev_spec))
+ self._src.set_decim_rate(self._decim)
+
+ # If no gain specified, set to midrange
+ if gain is None:
+ g = self._subdev.gain_range()
+ gain = (g[0]+g[1])/2.0
+
+ self._subdev.set_gain(gain)
+ self._cal = calibration
+ self.connect(self._src, self)
+
+ def tune(self, freq):
+ result = usrp.tune(self._src, 0, self._subdev, freq+self._cal)
+ # TODO: deal with residual
+
+ def rate(self):
+ return self._src.adc_rate()/self._decim
+
+class app_top_block(gr.top_block):
+ def __init__(self, options):
+ gr.top_block.__init__(self)
+ self.options = options
+
+ (usrp_decim, channel_decim, audio_decim,
+ channel_pass, channel_stop, demod) = demod_params[options.modulation]
+
+ USRP = usrp_src(options.rx_subdev_spec, # Daugherboard spec
+ usrp_decim, # IF decimation ratio
+ options.gain, # Receiver gain
+ options.calibration) # Frequency offset
+ USRP.tune(options.frequency)
+
+ if_rate = USRP.rate()
+ channel_rate = if_rate // channel_decim
+ audio_rate = channel_rate // audio_decim
+
+ CHAN_taps = optfir.low_pass(1.0, # Filter gain
+ if_rate, # Sample rate
+ channel_pass, # One sided modulation bandwidth
+ channel_stop, # One sided channel bandwidth
+ 0.1, # Passband ripple
+ 60) # Stopband attenuation
+
+ CHAN = gr.freq_xlating_fir_filter_ccf(channel_decim, # Decimation rate
+ CHAN_taps, # Filter taps
+ 0.0, # Offset frequency
+ if_rate) # Sample rate
+
+ RFSQL = gr.pwr_squelch_cc(options.rf_squelch, # Power threshold
+ 125.0/channel_rate, # Time constant
+ channel_rate/20, # 50ms rise/fall
+ False) # Zero, not gate output
+
+ AGC = gr.agc_cc(1.0/channel_rate, # Time constant
+ 1.0, # Reference power
+ 1.0, # Initial gain
+ 1.0) # Maximum gain
+
+ DEMOD = demod(channel_rate, audio_decim)
+
+ # From RF to audio
+ self.connect(USRP, CHAN, RFSQL, AGC, DEMOD)
+
+ # Optionally add CTCSS and RSAMP if needed
+ tail = DEMOD
+ if options.ctcss != None and options.ctcss > 60.0:
+ CTCSS = gr.ctcss_squelch_ff(audio_rate, # Sample rate
+ options.ctcss) # Squelch tone
+ self.connect(DEMOD, CTCSS)
+ tail = CTCSS
+
+ if options.output_rate != audio_rate:
+ out_lcm = gru.lcm(audio_rate, options.output_rate)
+ out_interp = int(out_lcm // audio_rate)
+ out_decim = int(out_lcm // options.output_rate)
+ RSAMP = blks2.rational_resampler_fff(out_interp, out_decim)
+ self.connect(tail, RSAMP)
+ tail = RSAMP
+
+ # Send to default audio output
+ AUDIO = audio.sink(options.output_rate, "")
+ self.connect(tail, AUDIO)
+
+def main():
+ parser = OptionParser(option_class=eng_option)
+ parser.add_option("-f", "--frequency", type="eng_float", default=None,
+ help="set receive frequency to Hz", metavar="Hz")
+ parser.add_option("-R", "--rx-subdev-spec", type="subdev",
+ help="select USRP Rx side A or B", metavar="SUBDEV")
+ parser.add_option("-c", "--calibration", type="eng_float", default=0.0,
+ help="set frequency offset to Hz", metavar="Hz")
+ parser.add_option("-g", "--gain", type="int", default=None,
+ help="set RF gain", metavar="dB")
+ parser.add_option("-m", "--modulation", type="choice", choices=('AM','FM','WFM'),
+ help="set modulation type (AM,FM)", metavar="TYPE")
+ parser.add_option("-o", "--output-rate", type="int", default=32000,
+ help="set audio output rate to RATE", metavar="RATE")
+ parser.add_option("-r", "--rf-squelch", type="eng_float", default=-50.0,
+ help="set RF squelch to dB", metavar="dB")
+ parser.add_option("-p", "--ctcss", type="float",
+ help="set CTCSS squelch to FREQ", metavar="FREQ")
+ (options, args) = parser.parse_args()
+
+ if options.frequency is None:
+ print "Must supply receive frequency with -f"
+ sys.exit(1)
+
+ if options.frequency < 1e6:
+ options.frequency *= 1e6
+
+ tb = app_top_block(options)
+ try:
+ tb.run()
+ except KeyboardInterrupt:
+ pass
+
+if __name__ == "__main__":
+ main()
projects / debian / gnuradio / blobdiff