2 # Copyright 2005,2006,2007 Free Software Foundation, Inc.
4 # This file is part of GNU Radio
6 # GNU Radio is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 3, or (at your option)
11 # GNU Radio is distributed in the hope that it will be useful,
12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 # GNU General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with GNU Radio; see the file COPYING. If not, write to
18 # the Free Software Foundation, Inc., 51 Franklin Street,
19 # Boston, MA 02110-1301, USA.
22 # See gnuradio-examples/python/digital for examples
25 differential BPSK modulation and demodulation.
28 from gnuradio import gr, gru, modulation_utils
29 from math import pi, sqrt
32 from pprint import pprint
34 # default values (used in __init__ and add_options)
35 _def_samples_per_symbol = 2
41 _def_costas_alpha = 0.15
44 _def_omega_relative_limit = 0.005
47 # /////////////////////////////////////////////////////////////////////////////
49 # /////////////////////////////////////////////////////////////////////////////
51 class dbpsk_mod(gr.hier_block2):
53 samples_per_symbol=_def_samples_per_symbol,
54 excess_bw=_def_excess_bw,
55 gray_code=_def_gray_code,
59 Hierarchical block for RRC-filtered differential BPSK modulation.
61 The input is a byte stream (unsigned char) and the
62 output is the complex modulated signal at baseband.
64 @param samples_per_symbol: samples per baud >= 2
65 @type samples_per_symbol: integer
66 @param excess_bw: Root-raised cosine filter excess bandwidth
67 @type excess_bw: float
68 @param gray_code: Tell modulator to Gray code the bits
70 @param verbose: Print information about modulator?
72 @param log: Log modulation data to files?
76 gr.hier_block2.__init__(self, "dbpsk_mod",
77 gr.io_signature(1,1,gr.sizeof_char), # Input signature
78 gr.io_signature(1,1,gr.sizeof_gr_complex)) # Output signature
80 self._samples_per_symbol = samples_per_symbol
81 self._excess_bw = excess_bw
82 self._gray_code = gray_code
84 if not isinstance(self._samples_per_symbol, int) or self._samples_per_symbol < 2:
85 raise TypeError, ("sbp must be an integer >= 2, is %d" % self._samples_per_symbol)
87 ntaps = 11 * self._samples_per_symbol
89 arity = pow(2,self.bits_per_symbol())
91 # turn bytes into k-bit vectors
93 gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
96 self.symbol_mapper = gr.map_bb(psk.binary_to_gray[arity])
98 self.symbol_mapper = gr.map_bb(psk.binary_to_ungray[arity])
100 self.diffenc = gr.diff_encoder_bb(arity)
102 self.chunks2symbols = gr.chunks_to_symbols_bc(psk.constellation[arity])
104 # pulse shaping filter
105 self.rrc_taps = gr.firdes.root_raised_cosine(
106 self._samples_per_symbol, # gain (samples_per_symbol since we're
107 # interpolating by samples_per_symbol)
108 self._samples_per_symbol, # sampling rate
110 self._excess_bw, # excess bandwidth (roll-off factor)
112 self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol,
116 self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
117 self.chunks2symbols, self.rrc_filter, self)
120 self._print_verbage()
123 self._setup_logging()
125 def samples_per_symbol(self):
126 return self._samples_per_symbol
128 def bits_per_symbol(self=None): # static method that's also callable on an instance
130 bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
132 def add_options(parser):
134 Adds DBPSK modulation-specific options to the standard parser
136 parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
137 help="set RRC excess bandwith factor [default=%default]")
138 parser.add_option("", "--no-gray-code", dest="gray_code",
139 action="store_false", default=True,
140 help="disable gray coding on modulated bits (PSK)")
141 add_options=staticmethod(add_options)
143 def extract_kwargs_from_options(options):
145 Given command line options, create dictionary suitable for passing to __init__
147 return modulation_utils.extract_kwargs_from_options(dbpsk_mod.__init__,
148 ('self', 'fg'), options)
149 extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
152 def _print_verbage(self):
154 print "bits per symbol = %d" % self.bits_per_symbol()
155 print "Gray code = %s" % self._gray_code
156 print "RRC roll-off factor = %.2f" % self._excess_bw
158 def _setup_logging(self):
159 print "Modulation logging turned on."
160 self.connect(self.bytes2chunks, gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
161 self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
162 self.connect(self.diffenc, gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
163 self.connect(self.chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
164 self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
167 # /////////////////////////////////////////////////////////////////////////////
170 # Differentially coherent detection of differentially encoded BPSK
171 # /////////////////////////////////////////////////////////////////////////////
173 class dbpsk_demod(gr.hier_block2):
176 samples_per_symbol=_def_samples_per_symbol,
177 excess_bw=_def_excess_bw,
178 costas_alpha=_def_costas_alpha,
179 gain_mu=_def_gain_mu,
181 omega_relative_limit=_def_omega_relative_limit,
182 gray_code=_def_gray_code,
183 verbose=_def_verbose,
186 Hierarchical block for RRC-filtered differential BPSK demodulation
188 The input is the complex modulated signal at baseband.
189 The output is a stream of bits packed 1 bit per byte (LSB)
191 @param samples_per_symbol: samples per symbol >= 2
192 @type samples_per_symbol: float
193 @param excess_bw: Root-raised cosine filter excess bandwidth
194 @type excess_bw: float
195 @param costas_alpha: loop filter gain
196 @type costas_alphas: float
197 @param gain_mu: for M&M block
199 @param mu: for M&M block
201 @param omega_relative_limit: for M&M block
202 @type omega_relative_limit: float
203 @param gray_code: Tell modulator to Gray code the bits
204 @type gray_code: bool
205 @param verbose: Print information about modulator?
207 @param debug: Print modualtion data to files?
211 gr.hier_block2.__init__(self, "dbpsk_demod",
212 gr.io_signature(1,1,gr.sizeof_gr_complex), # Input signature
213 gr.io_signature(1,1,gr.sizeof_char)) # Output signature
216 self._samples_per_symbol = samples_per_symbol
217 self._excess_bw = excess_bw
218 self._costas_alpha = costas_alpha
219 self._mm_gain_mu = gain_mu
221 self._mm_omega_relative_limit = omega_relative_limit
222 self._gray_code = gray_code
224 if samples_per_symbol < 2:
225 raise TypeError, "samples_per_symbol must be >= 2, is %r" % (samples_per_symbol,)
227 arity = pow(2,self.bits_per_symbol())
229 # Automatic gain control
230 scale = (1.0/16384.0)
231 self.pre_scaler = gr.multiply_const_cc(scale) # scale the signal from full-range to +-1
232 #self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
233 self.agc = gr.feedforward_agc_cc(16, 1.0)
237 ntaps = 11 * samples_per_symbol
238 self.rrc_taps = gr.firdes.root_raised_cosine(
240 self._samples_per_symbol, # sampling rate
242 self._excess_bw, # excess bandwidth (roll-off factor)
244 self.rrc_filter=gr.interp_fir_filter_ccf(1, self.rrc_taps)
246 # symbol clock recovery
247 self._mm_omega = self._samples_per_symbol
248 self._mm_gain_omega = .25 * self._mm_gain_mu * self._mm_gain_mu
249 self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
253 self.receiver=gr.mpsk_receiver_cc(arity, 0,
254 self._costas_alpha, self._costas_beta,
256 self._mm_mu, self._mm_gain_mu,
257 self._mm_omega, self._mm_gain_omega,
258 self._mm_omega_relative_limit)
260 # Using differential decoding
261 self.diffdec = gr.diff_phasor_cc()
263 # find closest constellation point
265 rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
266 self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
269 self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
271 self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[arity])
273 # unpack the k bit vector into a stream of bits
274 self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
276 # Connect and Initialize base class
277 self.connect(self, self.pre_scaler, self.agc, self.rrc_filter, self.receiver,
278 self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
281 self._print_verbage()
284 self._setup_logging()
286 def samples_per_symbol(self):
287 return self._samples_per_symbol
289 def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
291 bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
293 def _print_verbage(self):
294 print "\nDemodulator:"
295 print "bits per symbol: %d" % self.bits_per_symbol()
296 print "Gray code: %s" % self._gray_code
297 print "RRC roll-off factor: %.2f" % self._excess_bw
298 print "Costas Loop alpha: %.2e" % self._costas_alpha
299 print "Costas Loop beta: %.2e" % self._costas_beta
300 print "M&M mu: %.2f" % self._mm_mu
301 print "M&M mu gain: %.2e" % self._mm_gain_mu
302 print "M&M omega: %.2f" % self._mm_omega
303 print "M&M omega gain: %.2e" % self._mm_gain_omega
304 print "M&M omega limit: %.2f" % self._mm_omega_relative_limit
306 def _setup_logging(self):
307 print "Demodulation logging turned on."
308 self.connect(self.pre_scaler, gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
309 self.connect(self.agc, gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
310 self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
311 self.connect(self.receiver, gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
312 self.connect(self.diffdec, gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
313 self.connect(self.slicer, gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
314 self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
315 self.connect(self.unpack, gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
317 def add_options(parser):
319 Adds DBPSK demodulation-specific options to the standard parser
321 parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
322 help="set RRC excess bandwith factor [default=%default] (PSK)")
323 parser.add_option("", "--no-gray-code", dest="gray_code",
324 action="store_false", default=_def_gray_code,
325 help="disable gray coding on modulated bits (PSK)")
326 parser.add_option("", "--costas-alpha", type="float", default=None,
327 help="set Costas loop alpha value [default=%default] (PSK)")
328 parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu,
329 help="set M&M symbol sync loop gain mu value [default=%default] (GMSK/PSK)")
330 parser.add_option("", "--mu", type="float", default=_def_mu,
331 help="set M&M symbol sync loop mu value [default=%default] (GMSK/PSK)")
332 parser.add_option("", "--omega-relative-limit", type="float", default=_def_omega_relative_limit,
333 help="M&M clock recovery omega relative limit [default=%default] (GMSK/PSK)")
334 add_options=staticmethod(add_options)
336 def extract_kwargs_from_options(options):
338 Given command line options, create dictionary suitable for passing to __init__
340 return modulation_utils.extract_kwargs_from_options(
341 dbpsk_demod.__init__, ('self'), options)
342 extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
344 # Add these to the mod/demod registry
346 modulation_utils.add_type_1_mod('dbpsk', dbpsk_mod)
347 modulation_utils.add_type_1_demod('dbpsk', dbpsk_demod)