#!/usr/bin/env python # # Copyright 2005,2007,2011 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, eng_notation, window from gnuradio import audio from gnuradio import uhd from gnuradio.eng_option import eng_option from optparse import OptionParser import sys import math import struct sys.stderr.write("Warning: this is known to have issues on some machines+Python version combinations to seg fault due to the callback in bin_statitics. If you figure out why, we'd love to hear about it!\n") class tune(gr.feval_dd): """ This class allows C++ code to callback into python. """ def __init__(self, tb): gr.feval_dd.__init__(self) self.tb = tb def eval(self, ignore): """ This method is called from gr.bin_statistics_f when it wants to change the center frequency. This method tunes the front end to the new center frequency, and returns the new frequency as its result. """ try: # We use this try block so that if something goes wrong # from here down, at least we'll have a prayer of knowing # what went wrong. Without this, you get a very # mysterious: # # terminate called after throwing an instance of # 'Swig::DirectorMethodException' Aborted # # message on stderr. Not exactly helpful ;) new_freq = self.tb.set_next_freq() return new_freq except Exception, e: print "tune: Exception: ", e class parse_msg(object): def __init__(self, msg): self.center_freq = msg.arg1() self.vlen = int(msg.arg2()) assert(msg.length() == self.vlen * gr.sizeof_float) # FIXME consider using NumPy array t = msg.to_string() self.raw_data = t self.data = struct.unpack('%df' % (self.vlen,), t) class my_top_block(gr.top_block): def __init__(self): gr.top_block.__init__(self) usage = "usage: %prog [options] min_freq max_freq" parser = OptionParser(option_class=eng_option, usage=usage) parser.add_option("-a", "--args", type="string", default="", help="UHD device device address args [default=%default]") parser.add_option("", "--spec", type="string", default=None, help="Subdevice of UHD device where appropriate") parser.add_option("-A", "--antenna", type="string", default=None, help="select Rx Antenna where appropriate") parser.add_option("-s", "--samp-rate", type="eng_float", default=1e6, help="set sample rate [default=%default]") parser.add_option("-g", "--gain", type="eng_float", default=None, help="set gain in dB (default is midpoint)") parser.add_option("", "--tune-delay", type="eng_float", default=1e-3, metavar="SECS", help="time to delay (in seconds) after changing frequency [default=%default]") parser.add_option("", "--dwell-delay", type="eng_float", default=10e-3, metavar="SECS", help="time to dwell (in seconds) at a given frequncy [default=%default]") parser.add_option("-F", "--fft-size", type="int", default=256, help="specify number of FFT bins [default=%default]") parser.add_option("", "--real-time", action="store_true", default=False, help="Attempt to enable real-time scheduling") (options, args) = parser.parse_args() if len(args) != 2: parser.print_help() sys.exit(1) self.min_freq = eng_notation.str_to_num(args[0]) self.max_freq = eng_notation.str_to_num(args[1]) if self.min_freq > self.max_freq: # swap them self.min_freq, self.max_freq = self.max_freq, self.min_freq self.fft_size = options.fft_size if not options.real_time: realtime = False else: # Attempt to enable realtime scheduling r = gr.enable_realtime_scheduling() if r == gr.RT_OK: realtime = True else: realtime = False print "Note: failed to enable realtime scheduling" # build graph self.u = uhd.usrp_source(device_addr=options.args, io_type=uhd.io_type.COMPLEX_FLOAT32, num_channels=1) usrp_rate = options.samp_rate self.u.set_samp_rate(usrp_rate) dev_rate = self.u.get_samp_rate() s2v = gr.stream_to_vector(gr.sizeof_gr_complex, self.fft_size) mywindow = window.blackmanharris(self.fft_size) fft = gr.fft_vcc(self.fft_size, True, mywindow) power = 0 for tap in mywindow: power += tap*tap c2mag = gr.complex_to_mag_squared(self.fft_size) # FIXME the log10 primitive is dog slow log = gr.nlog10_ff(10, self.fft_size, -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size)) # Set the freq_step to 75% of the actual data throughput. # This allows us to discard the bins on both ends of the spectrum. self.freq_step = 0.75 * usrp_rate self.min_center_freq = self.min_freq + self.freq_step/2 nsteps = math.ceil((self.max_freq - self.min_freq) / self.freq_step) self.max_center_freq = self.min_center_freq + (nsteps * self.freq_step) self.next_freq = self.min_center_freq tune_delay = max(0, int(round(options.tune_delay * usrp_rate / self.fft_size))) # in fft_frames dwell_delay = max(1, int(round(options.dwell_delay * usrp_rate / self.fft_size))) # in fft_frames self.msgq = gr.msg_queue(16) self._tune_callback = tune(self) # hang on to this to keep it from being GC'd stats = gr.bin_statistics_f(self.fft_size, self.msgq, self._tune_callback, tune_delay, dwell_delay) # FIXME leave out the log10 until we speed it up #self.connect(self.u, s2v, fft, c2mag, log, stats) self.connect(self.u, s2v, fft, c2mag, stats) if options.gain is None: # if no gain was specified, use the mid-point in dB g = self.u.get_gain_range() options.gain = float(g.start()+g.stop())/2.0 self.set_gain(options.gain) print "gain =", options.gain # Set the subdevice spec if(options.spec): self.u.set_subdev_spec(options.spec, 0) # Set the antenna if(options.antenna): self.u.set_antenna(options.antenna, 0) def set_next_freq(self): target_freq = self.next_freq self.next_freq = self.next_freq + self.freq_step if self.next_freq >= self.max_center_freq: self.next_freq = self.min_center_freq if not self.set_freq(target_freq): print "Failed to set frequency to", target_freq sys.exit(1) return target_freq def set_freq(self, target_freq): """ Set the center frequency we're interested in. @param target_freq: frequency in Hz @rypte: bool """ r = self.u.set_center_freq(target_freq) if r: return True return False def set_gain(self, gain): self.u.set_gain(gain) def main_loop(tb): while 1: # Get the next message sent from the C++ code (blocking call). # It contains the center frequency and the mag squared of the fft m = parse_msg(tb.msgq.delete_head()) # Print center freq so we know that something is happening... print m.center_freq # FIXME do something useful with the data... # m.data are the mag_squared of the fft output (they are in the # standard order. I.e., bin 0 == DC.) # You'll probably want to do the equivalent of "fftshift" on them # m.raw_data is a string that contains the binary floats. # You could write this as binary to a file. if __name__ == '__main__': tb = my_top_block() try: tb.start() main_loop(tb) except KeyboardInterrupt: pass