diff options
Diffstat (limited to 'gnuradio-examples/python')
| -rw-r--r-- | gnuradio-examples/python/hier/Makefile.am | 1 | ||||
| -rw-r--r-- | gnuradio-examples/python/hier/dect/Makefile.am | 28 | ||||
| -rw-r--r-- | gnuradio-examples/python/hier/dect/README | 45 | ||||
| -rw-r--r-- | gnuradio-examples/python/hier/dect/dect_receiver.py | 91 | ||||
| -rw-r--r-- | gnuradio-examples/python/hier/dect/gmsk2.py | 300 | ||||
| -rwxr-xr-x | gnuradio-examples/python/hier/dect/usrp_dect.py | 66 | ||||
| -rw-r--r-- | gnuradio-examples/python/hier/dect/usrp_source.py | 126 |
7 files changed, 657 insertions, 0 deletions
diff --git a/gnuradio-examples/python/hier/Makefile.am b/gnuradio-examples/python/hier/Makefile.am index f9931b3e9..c212ade19 100644 --- a/gnuradio-examples/python/hier/Makefile.am +++ b/gnuradio-examples/python/hier/Makefile.am @@ -21,6 +21,7 @@ SUBDIRS = \ audio \ + dect \ digital \ ofdm \ networking \ diff --git a/gnuradio-examples/python/hier/dect/Makefile.am b/gnuradio-examples/python/hier/dect/Makefile.am new file mode 100644 index 000000000..e676ee3b4 --- /dev/null +++ b/gnuradio-examples/python/hier/dect/Makefile.am @@ -0,0 +1,28 @@ +# +# Copyright 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 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. +# + +EXTRA_DIST = \ + README \ + dect_receiver.py \ + usrp_source.py \ + usrp_dect.py + +MOSTLYCLEANFILES = *.pyc *~ diff --git a/gnuradio-examples/python/hier/dect/README b/gnuradio-examples/python/hier/dect/README new file mode 100644 index 000000000..231b1af67 --- /dev/null +++ b/gnuradio-examples/python/hier/dect/README @@ -0,0 +1,45 @@ +This directory contains a work in progress service monitor for DECT +digital cordless phone base stations and handsets. + + +Status +------ + +2007 Apr 03 - Development on hold. +2007 Feb 11 - Added GMSK demodulation and option to log to file +2007 Feb 10 - Able to tune and log filtered baseband to file + + +Files +----- + +usrp_dect.py - DECT receiver application + +dect_receiver.py - Top-level hierarchical block (new type) implementing + receiver + +usrp_source.py - Hierarchical block (new type) implementing a USRP + complex source, with convenience functions for tuning, + gain, decimation, etc. + +gmsk2.py - Hierarchical block (new type) implementing GMSK + modulation and demodulation. This will eventually go + into the core blksimpl directory + +DECT Modulation Details +----------------------- + +In the US, the FCC has allocated four carrier frequencies for DECT usage: + +Channel Frequency +------- --------- + 1 1921.536 MHz + 2 1923.264 MHz + 3 1924.992 MHz + 4 1926.720 MHz + +These are spaced at 1.728 MHz intervals. + +The DECT PHY uses GMSK with a 0.5 bandwidth-time product at 1.152 Msym/sec, +for an occupied bandwidth (99% power) of 1.186 MHz (1.03 x symbol rate.) + diff --git a/gnuradio-examples/python/hier/dect/dect_receiver.py b/gnuradio-examples/python/hier/dect/dect_receiver.py new file mode 100644 index 000000000..491159a31 --- /dev/null +++ b/gnuradio-examples/python/hier/dect/dect_receiver.py @@ -0,0 +1,91 @@ +#!/usr/bin/env python +# +# Copyright 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 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, optfir +from usrp_source import usrp_source_c +from gmsk2 import gmsk2_demod + +_dect_symbol_rate = 1.152e6 +_dect_occupied_bandwidth = _dect_symbol_rate * 1.03 # BT=0.5 +_dect_channel_bandwidth = 1.728e6 + +# Top-level hierarchical block that implements DECT demodulation and +# decoding. +class dect_receiver(gr.hier_block2): + def __init__(self, options): + gr.hier_block2.__init__(self, + "dect_receiver", # Block typename + gr.io_signature(0,0,0), # Input signature + gr.io_signature(0,0,0)) # Output signature + self._options = options + + # Need greater than 2 samples per symbol. This makes a decimation + # rate of 26 and a samples per symbol of 2.136752 + if_rate = 2.461538e6 + self._usrp = usrp_source_c(self, + which=0, + subdev_spec=options.rx_subdev_spec, + if_rate=if_rate, + gain=options.gain, + freq=options.freq, + calibration=options.calibration, + verbose=options.verbose) + + # Filter baseband to 1.186 MHz passband, 1.728 MHz stopband + chan_taps = optfir.low_pass(1.0, # Gain + if_rate, # Sample rate + _dect_occupied_bandwidth/2, # One sided modulation bandwidth + _dect_channel_bandwidth/2, # One sided channel bandwidth + 1.0, # Passband ripple (db) + 60) # Stopband attenuation (db) + if self._options.verbose: + print "Channel filter has", len(chan_taps), "taps" + self._channel_filter = gr.freq_xlating_fir_filter_ccf(1, # Decimation rate + chan_taps, # Filter taps + 0.0, # Offset frequency + if_rate) # Sample rate + + self._demod = gmsk2_demod(samples_per_symbol=if_rate/_dect_symbol_rate, + verbose=options.verbose) + + # Define and connect components + self.define_component("usrp", self._usrp) + self.define_component("channel", self._channel_filter) + self.define_component("demod", self._demod) + self.define_component("sink", gr.null_sink(gr.sizeof_char)) + self.connect("usrp", 0, "channel", 0) + self.connect("channel", 0, "demod", 0) + self.connect("demod", 0, "sink", 0) + + # Log baseband to file if requested + if options.log_baseband is not None: + if options.verbose: + print "Logging baseband to file", options.log_baseband + self.define_component("baseband_log", gr.file_sink(gr.sizeof_gr_complex, options.log_baseband)) + self.connect("channel", 0, "baseband_log", 0) + + # Log demodulator output to file if requested + if options.log_demod is not None: + if options.verbose: + print "Logging demodulator to file", options.log_demod + self.define_component("demod_log", gr.file_sink(gr.sizeof_char, options.log_demod)) + self.connect("demod", 0, "demod_log", 0) diff --git a/gnuradio-examples/python/hier/dect/gmsk2.py b/gnuradio-examples/python/hier/dect/gmsk2.py new file mode 100644 index 000000000..578873eed --- /dev/null +++ b/gnuradio-examples/python/hier/dect/gmsk2.py @@ -0,0 +1,300 @@ +# +# GMSK modulation and demodulation. +# +# +# Copyright 2005,2006,2007 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 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. +# + +# See gnuradio-examples/python/digital for examples + +from gnuradio import gr +from gnuradio import modulation_utils +from math import pi +import Numeric +from pprint import pprint +import inspect + +# default values (used in __init__ and add_options) +_def_samples_per_symbol = 2 +_def_bt = 0.35 +_def_verbose = False +_def_log = False + +_def_gain_mu = 0.05 +_def_mu = 0.5 +_def_freq_error = 0.0 +_def_omega_relative_limit = 0.005 + + +# ///////////////////////////////////////////////////////////////////////////// +# GMSK modulator +# ///////////////////////////////////////////////////////////////////////////// + +class gmsk2_mod(gr.hier_block2): + + def __init__(self, + samples_per_symbol=_def_samples_per_symbol, + bt=_def_bt, + verbose=_def_verbose, + log=_def_log): + """ + Hierarchical block for Gaussian Minimum Shift Key (GMSK) + modulation. + + The input is a byte stream (unsigned char) and the + output is the complex modulated signal at baseband. + + @param samples_per_symbol: samples per baud >= 2 + @type samples_per_symbol: integer + @param bt: Gaussian filter bandwidth * symbol time + @type bt: float + @param verbose: Print information about modulator? + @type verbose: bool + @param debug: Print modualtion data to files? + @type debug: bool + """ + gr.hier_block2.__init__(self, + "gmsk2_mod", # Block typename + gr.io_signature(1,1,gr.sizeof_char), # Input signature + gr.io_signature(1,1,gr.sizeof_gr_complex)) # Output signature + + self._samples_per_symbol = samples_per_symbol + self._bt = bt + + if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2: + raise TypeError, ("samples_per_symbol must be an integer >= 2, is %r" % (samples_per_symbol,)) + + ntaps = 4 * samples_per_symbol # up to 3 bits in filter at once + sensitivity = (pi / 2) / samples_per_symbol # phase change per bit = pi / 2 + + # Turn it into NRZ data. + self.nrz = gr.bytes_to_syms() + + # Form Gaussian filter + # Generate Gaussian response (Needs to be convolved with window below). + self.gaussian_taps = gr.firdes.gaussian( + 1, # gain + samples_per_symbol, # symbol_rate + bt, # bandwidth * symbol time + ntaps # number of taps + ) + + self.sqwave = (1,) * samples_per_symbol # rectangular window + self.taps = Numeric.convolve(Numeric.array(self.gaussian_taps),Numeric.array(self.sqwave)) + self.gaussian_filter = gr.interp_fir_filter_fff(samples_per_symbol, self.taps) + + # FM modulation + self.fmmod = gr.frequency_modulator_fc(sensitivity) + + if verbose: + self._print_verbage() + + # Define and connect components + self.define_component("nrz", self.nrz) + self.define_component("filter", self.gaussian_filter) + self.define_component("fmmod", self.fmmod) + self.connect("self", 0, "nrz", 0) + self.connect("nrz", 0, "filter", 0) + self.connect("filter", 0, "fmmod", 0) + self.connect("fmmod", 0, "self", 0) + + if log: + self._setup_logging() + + def samples_per_symbol(self): + return self._samples_per_symbol + + def bits_per_symbol(self=None): # staticmethod that's also callable on an instance + return 1 + bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. + + + def _print_verbage(self): + print "bits per symbol = %d" % self.bits_per_symbol() + print "Gaussian filter bt = %.2f" % self._bt + + + def _setup_logging(self): + print "Modulation logging turned on." + self.define_component("nrz_log", gr.file_sink(gr.sizeof_float, "nrz.dat")) + self.define_component("filter_log", gr.file_sink(gr.sizeof_float, "gaussian_filter.dat")) + self.define_component("fmmod_log", gr.file_sink(gr.sizeof_gr_complex, "fmmod.dat")) + self.connect("nrz", 0, "nrz_log", 0) + self.connect("filter", 0, "filter_log", 0) + self.connect("fmmod", 0, "fmmod_log", 0) + + def add_options(parser): + """ + Adds GMSK modulation-specific options to the standard parser + """ + parser.add_option("", "--bt", type="float", default=_def_bt, + help="set bandwidth-time product [default=%default] (GMSK)") + add_options=staticmethod(add_options) + + # FIXME: figure out what has to change for gr.hier_block2 version + #def extract_kwargs_from_options(options): + # """ + # Given command line options, create dictionary suitable for passing to __init__ + # """ + # return modulation_utils.extract_kwargs_from_options(gmsk_mod.__init__, + # ('self', 'fg'), options) + #extract_kwargs_from_options=staticmethod(extract_kwargs_from_options) + + +# ///////////////////////////////////////////////////////////////////////////// +# GMSK demodulator +# ///////////////////////////////////////////////////////////////////////////// + +class gmsk2_demod(gr.hier_block2): + + def __init__(self, + samples_per_symbol=_def_samples_per_symbol, + gain_mu=_def_gain_mu, + mu=_def_mu, + omega_relative_limit=_def_omega_relative_limit, + freq_error=_def_freq_error, + verbose=_def_verbose, + log=_def_log): + """ + Hierarchical block for Gaussian Minimum Shift Key (GMSK) + demodulation. + + The input is the complex modulated signal at baseband. + The output is a stream of bits packed 1 bit per byte (the LSB) + + @param samples_per_symbol: samples per baud + @type samples_per_symbol: integer + @param verbose: Print information about modulator? + @type verbose: bool + @param log: Print modualtion data to files? + @type log: bool + + Clock recovery parameters. These all have reasonble defaults. + + @param gain_mu: controls rate of mu adjustment + @type gain_mu: float + @param mu: fractional delay [0.0, 1.0] + @type mu: float + @param omega_relative_limit: sets max variation in omega + @type omega_relative_limit: float, typically 0.000200 (200 ppm) + @param freq_error: bit rate error as a fraction + @param float + """ + + gr.hier_block2.__init__(self, + "gmsk2_demod", # Block typename + gr.io_signature(1,1,gr.sizeof_gr_complex), # Input signature + gr.io_signature(1,1,gr.sizeof_char)) # Output signature + + self._samples_per_symbol = samples_per_symbol + self._gain_mu = gain_mu + self._mu = mu + self._omega_relative_limit = omega_relative_limit + self._freq_error = freq_error + + if samples_per_symbol < 2: + raise TypeError, "samples_per_symbol >= 2, is %f" % samples_per_symbol + + self._omega = samples_per_symbol*(1+self._freq_error) + + self._gain_omega = .25 * self._gain_mu * self._gain_mu # critically damped + + # Demodulate FM + sensitivity = (pi / 2) / samples_per_symbol + self.fmdemod = gr.quadrature_demod_cf(1.0 / sensitivity) + + # the clock recovery block tracks the symbol clock and resamples as needed. + # the output of the block is a stream of soft symbols (float) + self.clock_recovery = gr.clock_recovery_mm_ff(self._omega, self._gain_omega, + self._mu, self._gain_mu, + self._omega_relative_limit) + + # slice the floats at 0, outputting 1 bit (the LSB of the output byte) per sample + self.slicer = gr.binary_slicer_fb() + + if verbose: + self._print_verbage() + + # Define and connect components + self.define_component("fmdemod", self.fmdemod) + self.define_component("clock_recovery", self.clock_recovery) + self.define_component("slicer", self.slicer) + self.connect("self", 0, "fmdemod", 0) + self.connect("fmdemod", 0, "clock_recovery", 0) + self.connect("clock_recovery", 0, "slicer", 0) + self.connect("slicer", 0, "self", 0) + + if log: + self._setup_logging() + + def samples_per_symbol(self): + return self._samples_per_symbol + + def bits_per_symbol(self=None): # staticmethod that's also callable on an instance + return 1 + bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. + + + def _print_verbage(self): + print "bits per symbol = %d" % self.bits_per_symbol() + print "M&M clock recovery omega = %f" % self._omega + print "M&M clock recovery gain mu = %f" % self._gain_mu + print "M&M clock recovery mu = %f" % self._mu + print "M&M clock recovery omega rel. limit = %f" % self._omega_relative_limit + print "frequency error = %f" % self._freq_error + + + def _setup_logging(self): + print "Demodulation logging turned on." + self.define_component("fmdemod_log", gr.file_sink(gr.sizeof_float, "fmdemod.dat")) + self.define_component("clock_recovery_log", gr.file_sink(gr.sizeof_float, "clock_recovery.dat")) + self.define_component("slicer_log", gr.file_sink(gr.sizeof_char, "slicer.dat")) + self.connect("fmdemod", 0, "fmdemod_log", 0) + self.connect("clock_recovery", 0, "clock_recovery_log", 0) + self.connect("slicer", 0, "slicer_log", 0) + + def add_options(parser): + """ + Adds GMSK demodulation-specific options to the standard parser + """ + parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu, + help="M&M clock recovery gain mu [default=%default] (GMSK/PSK)") + parser.add_option("", "--mu", type="float", default=_def_mu, + help="M&M clock recovery mu [default=%default] (GMSK/PSK)") + parser.add_option("", "--omega-relative-limit", type="float", default=_def_omega_relative_limit, + help="M&M clock recovery omega relative limit [default=%default] (GMSK/PSK)") + parser.add_option("", "--freq-error", type="float", default=_def_freq_error, + help="M&M clock recovery frequency error [default=%default] (GMSK)") + add_options=staticmethod(add_options) + + # FIXME: figure out what this is for gr.hier_block2 version + #def extract_kwargs_from_options(options): + # """ + # Given command line options, create dictionary suitable for passing to __init__ + # """ + # return modulation_utils.extract_kwargs_from_options(gmsk_demod.__init__, + # ('self', 'fg'), options) + #extract_kwargs_from_options=staticmethod(extract_kwargs_from_options) + +# +# Add these to the mod/demod registry +# +modulation_utils.add_type_1_mod('gmsk2', gmsk2_mod) +modulation_utils.add_type_1_demod('gmsk2', gmsk2_demod) diff --git a/gnuradio-examples/python/hier/dect/usrp_dect.py b/gnuradio-examples/python/hier/dect/usrp_dect.py new file mode 100755 index 000000000..8fe15932d --- /dev/null +++ b/gnuradio-examples/python/hier/dect/usrp_dect.py @@ -0,0 +1,66 @@ +#!/usr/bin/env python +# +# Copyright 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 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, eng_notation +from gnuradio.eng_option import eng_option +from optparse import OptionParser +from dect_receiver import dect_receiver +import sys + +def main(): + parser = OptionParser(option_class=eng_option) + parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None, + help="select USRP Rx side A or B (default=first one with a daughterboard)") + parser.add_option("-f", "--freq", type="eng_float", default=None, + help="set frequency to FREQ", metavar="FREQ") + parser.add_option("", "--calibration", type="eng_float", default=0.0, + help="set frequency calibration offset to FREQ") + parser.add_option("-g", "--gain", type="eng_float", default=None, + help="set gain in dB (default is midpoint)") + parser.add_option("-v", "--verbose", action="store_true", default=False, + help="print extra debugging info") + parser.add_option("", "--log-baseband", default=None, + help="log filtered baseband to file") + parser.add_option("", "--log-demod", default=None, + help="log demodulator output to file") + (options, args) = parser.parse_args() + + if len(sys.argv) == 1 or len(args) != 0: + parser.print_help() + sys.exit(1) + + # Create an instance of a hierarchical block + top_block = dect_receiver(options) + + # Create an instance of a runtime, passing it the top block + # to process + runtime = gr.runtime(top_block) + + try: + # Run forever + runtime.run() + except KeyboardInterrupt: + # Ctrl-C exits + pass + +if __name__ == '__main__': + main () diff --git a/gnuradio-examples/python/hier/dect/usrp_source.py b/gnuradio-examples/python/hier/dect/usrp_source.py new file mode 100644 index 000000000..16949998b --- /dev/null +++ b/gnuradio-examples/python/hier/dect/usrp_source.py @@ -0,0 +1,126 @@ +#!/usr/bin/env python +# +# Copyright 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 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, usrp, eng_notation +n2s = eng_notation.num_to_str + +# Hierarchical block implementing a USRP source for complex floats, +# with convenience functions for gain, tune, decimation, etc. +# +class usrp_source_c(gr.hier_block2): + """ + Create a USRP source object supplying complex floats. + """ + def __init__(self, which=0, subdev_spec=None, gain=None, if_rate=None, + freq=0.0, calibration=0.0, verbose=False): + # Call hierarchical block constructor + gr.hier_block2.__init__(self, + "usrp_source_c", # Block typename + gr.io_signature(0,0,0), # Input signature + gr.io_signature(1,1,gr.sizeof_gr_complex)) # Output signature + + self._verbose = verbose + self._u = usrp.source_c(which) + if self._verbose: + print 'ADC sample rate is', n2s(self._u.adc_rate()), "sps" + self.set_subdev(subdev_spec) + self.set_if_rate(if_rate) + self.set_gain(gain) + self.set_calibration(calibration) + self.tune(freq) + + self.define_component("usrp", self._u) + self.connect("usrp", 0, "self", 0) + + def set_subdev(self, subdev_spec): + if subdev_spec is None: + subdev_spec = self.pick_subdevice() + self._subdev = usrp.selected_subdev(self._u, subdev_spec) + self._u.set_mux(usrp.determine_rx_mux_value(self._u, subdev_spec)) + if self._verbose: + print 'RX using', self._subdev.name(), 'daughterboard' + + def pick_subdevice(self): + """ + The user didn't specify a subdevice. + If there's a daughterboard on A, select A. + If there's a daughterboard on B, select B. + Otherwise, select A. + """ + if self._u.db[0][0].dbid() >= 0: # dbid is < 0 if there's no d'board or a problem + return (0, 0) + if self._u.db[1][0].dbid() >= 0: + return (1, 0) + return (0, 0) + + def set_if_rate(self, if_rate): + # If no IF rate specified, set to maximum decimation + if if_rate is None: + self._decim = 256 + else: + self._decim = int(self._u.adc_rate()/if_rate) + + self._u.set_decim_rate(self._decim) + self._if_rate = self._u.adc_rate()/self._decim + + if self._verbose: + print "USRP decimation rate is", self._decim + print "USRP IF rate is", n2s(self._if_rate), "sps" + + def set_gain(self, gain): + # If no gain specified, set to midrange + if gain is None: + g = self._subdev.gain_range() + gain = (g[0]+g[1])/2.0 + self._gain = gain + self._subdev.set_gain(self._gain) + + def set_calibration(self, calibration): + self._cal = calibration + if self._verbose: + print "Using frequency calibration offset of", n2s(calibration), "Hz" + + def tune(self, freq): + """ + Set the center frequency we're interested in. + + @param target_freq: frequency in Hz + @type: 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 down converter. + """ + self._tune_result = usrp.tune(self._u, 0, self._subdev, freq+self._cal) + if self._tune_result: + if self._verbose: + print "Baseband frequency is", n2s(self._tune_result.baseband_freq), "Hz" + print "DXC frequency is", n2s(self._tune_result.dxc_freq), "Hz" + print "Center frequency is", n2s(freq), "Hz" + print "Residual frequency is", n2s(self._tune_result.residual_freq), "Hz" + return True + + return False + +if __name__ == '__main__': + src = usrp_source_c(verbose=True) |