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Diffstat (limited to 'gnuradio-examples/python/hier/digital/transmit_path.py')
| -rw-r--r-- | gnuradio-examples/python/hier/digital/transmit_path.py | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/gnuradio-examples/python/hier/digital/transmit_path.py b/gnuradio-examples/python/hier/digital/transmit_path.py new file mode 100644 index 0000000000..c517210aef --- /dev/null +++ b/gnuradio-examples/python/hier/digital/transmit_path.py @@ -0,0 +1,239 @@ +# +# Copyright 2005,2006 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, gru, blks2 +from gnuradio import usrp +from gnuradio import eng_notation + +import copy +import sys + +# from current dir +from pick_bitrate import pick_tx_bitrate + +# ///////////////////////////////////////////////////////////////////////////// +# transmit path +# ///////////////////////////////////////////////////////////////////////////// + +class transmit_path(gr.hier_block2): + def __init__(self, modulator_class, options): + ''' + See below for what options should hold + ''' + + gr.hier_block2.__init__(self, "transmit_path", + gr.io_signature(0,0,0), # Input signature + gr.io_signature(0,0,0)) # Output signature + + options = copy.copy(options) # make a copy so we can destructively modify + + self._verbose = options.verbose + self._tx_freq = options.tx_freq # tranmitter's center frequency + self._tx_amplitude = options.tx_amplitude # digital amplitude sent to USRP + self._tx_subdev_spec = options.tx_subdev_spec # daughterboard to use + self._bitrate = options.bitrate # desired bit rate + self._interp = options.interp # interpolating rate for the USRP (prelim) + self._samples_per_symbol = options.samples_per_symbol # desired samples/baud + self._fusb_block_size = options.fusb_block_size # usb info for USRP + self._fusb_nblocks = options.fusb_nblocks # usb info for USRP + + self._modulator_class = modulator_class # the modulator_class we are using + + if self._tx_freq is None: + sys.stderr.write("-f FREQ or --freq FREQ or --tx-freq FREQ must be specified\n") + raise SystemExit + + # Set up USRP sink; also adjusts interp, samples_per_symbol, and bitrate + self._setup_usrp_sink() + + # copy the final answers back into options for use by modulator + options.samples_per_symbol = self._samples_per_symbol + options.bitrate = self._bitrate + options.interp = self._interp + + # Get mod_kwargs + mod_kwargs = self._modulator_class.extract_kwargs_from_options(options) + + # Set center frequency of USRP + ok = self.set_freq(self._tx_freq) + if not ok: + print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(self._tx_freq),) + raise ValueError + + # transmitter + self.packet_transmitter = \ + blks2.mod_pkts(self._modulator_class(**mod_kwargs), + access_code=None, + msgq_limit=4, + pad_for_usrp=True) + + # Set the USRP for maximum transmit gain + # (Note that on the RFX cards this is a nop.) + self.set_gain(self.subdev.gain_range()[0]) + + self.amp = gr.multiply_const_cc(1) + self.set_tx_amplitude(self._tx_amplitude) + + # enable Auto Transmit/Receive switching + self.set_auto_tr(True) + + # Display some information about the setup + if self._verbose: + self._print_verbage() + + # Define the components + self.define_component("packet_transmitter", self.packet_transmitter) + self.define_component("amp", self.amp) + self.define_component("usrp", self.u) + + # Connect components in the flowgraph; set amp component to the output of this block + self.connect("packet_transmitter", 0, "amp", 0) + self.connect("amp", 0, "usrp", 0) + + def _setup_usrp_sink(self): + """ + Creates a USRP sink, determines the settings for best bitrate, + and attaches to the transmitter's subdevice. + """ + self.u = usrp.sink_c(fusb_block_size=self._fusb_block_size, + fusb_nblocks=self._fusb_nblocks) + dac_rate = self.u.dac_rate(); + + # derive values of bitrate, samples_per_symbol, and interp from desired info + (self._bitrate, self._samples_per_symbol, self._interp) = \ + pick_tx_bitrate(self._bitrate, self._modulator_class.bits_per_symbol(), + self._samples_per_symbol, self._interp, dac_rate) + + self.u.set_interp_rate(self._interp) + + # determine the daughterboard subdevice we're using + if self._tx_subdev_spec is None: + self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u) + self.u.set_mux(usrp.determine_tx_mux_value(self.u, self._tx_subdev_spec)) + self.subdev = usrp.selected_subdev(self.u, self._tx_subdev_spec) + + + def set_freq(self, target_freq): + """ + Set the center frequency we're interested in. + + @param target_freq: frequency in Hz + @rypte: bool + + Tuning is a two step process. First we ask the front-end to + tune as close to the desired frequency as it can. Then we use + the result of that operation and our target_frequency to + determine the value for the digital up converter. + """ + r = self.u.tune(self.subdev._which, self.subdev, target_freq) + if r: + return True + + return False + + def set_gain(self, gain): + """ + Sets the analog gain in the USRP + """ + self.gain = gain + self.subdev.set_gain(gain) + + def set_tx_amplitude(self, ampl): + """ + Sets the transmit amplitude sent to the USRP + @param: ampl 0 <= ampl < 32768. Try 8000 + """ + self._tx_amplitude = max(0.0, min(ampl, 32767.0)) + self.amp.set_k(self._tx_amplitude) + + def set_auto_tr(self, enable): + """ + Turns on auto transmit/receive of USRP daughterboard (if exits; else ignored) + """ + return self.subdev.set_auto_tr(enable) + + def send_pkt(self, payload='', eof=False): + """ + Calls the transmitter method to send a packet + """ + return self.packet_transmitter.send_pkt(payload, eof) + + def bitrate(self): + return self._bitrate + + def samples_per_symbol(self): + return self._samples_per_symbol + + def interp(self): + return self._interp + + def add_options(normal, expert): + """ + Adds transmitter-specific options to the Options Parser + """ + add_freq_option(normal) + if not normal.has_option('--bitrate'): + normal.add_option("-r", "--bitrate", type="eng_float", default=None, + help="specify bitrate. samples-per-symbol and interp/decim will be derived.") + normal.add_option("-T", "--tx-subdev-spec", type="subdev", default=None, + help="select USRP Tx side A or B") + normal.add_option("", "--tx-amplitude", type="eng_float", default=12000, metavar="AMPL", + help="set transmitter digital amplitude: 0 <= AMPL < 32768 [default=%default]") + normal.add_option("-v", "--verbose", action="store_true", default=False) + + expert.add_option("-S", "--samples-per-symbol", type="int", default=None, + help="set samples/symbol [default=%default]") + expert.add_option("", "--tx-freq", type="eng_float", default=None, + help="set transmit frequency to FREQ [default=%default]", metavar="FREQ") + expert.add_option("-i", "--interp", type="intx", default=None, + help="set fpga interpolation rate to INTERP [default=%default]") + expert.add_option("", "--log", action="store_true", default=False, + help="Log all parts of flow graph to file (CAUTION: lots of data)") + + # Make a static method to call before instantiation + add_options = staticmethod(add_options) + + def _print_verbage(self): + """ + Prints information about the transmit path + """ + print "Using TX d'board %s" % (self.subdev.side_and_name(),) + print "Tx amplitude %s" % (self._tx_amplitude) + print "modulation: %s" % (self._modulator_class.__name__) + print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate)) + print "samples/symbol: %3d" % (self._samples_per_symbol) + print "interp: %3d" % (self._interp) + print "Tx Frequency: %s" % (eng_notation.num_to_str(self._tx_freq)) + + +def add_freq_option(parser): + """ + Hackery that has the -f / --freq option set both tx_freq and rx_freq + """ + def freq_callback(option, opt_str, value, parser): + parser.values.rx_freq = value + parser.values.tx_freq = value + + if not parser.has_option('--freq'): + parser.add_option('-f', '--freq', type="eng_float", + action="callback", callback=freq_callback, + help="set Tx and/or Rx frequency to FREQ [default=%default]", + metavar="FREQ") |