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 QPSK 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 = None
44 _def_omega_relative_limit = 0.005
47 # /////////////////////////////////////////////////////////////////////////////
49 # /////////////////////////////////////////////////////////////////////////////
51 class qam64_mod(gr.hier_block2):
54 samples_per_symbol=_def_samples_per_symbol,
55 excess_bw=_def_excess_bw,
56 gray_code=_def_gray_code,
61 Hierarchical block for RRC-filtered QPSK modulation.
63 The input is a byte stream (unsigned char) and the
64 output is the complex modulated signal at baseband.
66 @param samples_per_symbol: samples per symbol >= 2
67 @type samples_per_symbol: integer
68 @param excess_bw: Root-raised cosine filter excess bandwidth
69 @type excess_bw: float
70 @param gray_code: Tell modulator to Gray code the bits
72 @param verbose: Print information about modulator?
74 @param debug: Print modualtion data to files?
78 gr.hier_block2.__init__(self, "qam64_mod",
79 gr.io_signature(1, 1, gr.sizeof_char), # Input signature
80 gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
81 self._samples_per_symbol = samples_per_symbol
82 self._excess_bw = excess_bw
83 self._gray_code = gray_code
85 if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
86 raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
88 ntaps = 11 * samples_per_symbol
90 arity = pow(2, self.bits_per_symbol())
92 # turn bytes into k-bit vectors
94 gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
97 self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
99 self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
101 self.diffenc = gr.diff_encoder_bb(arity)
104 print "constellation with %d arity" % arity
105 rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
106 self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
108 # pulse shaping filter
109 self.rrc_taps = gr.firdes.root_raised_cosine(
110 self._samples_per_symbol, # gain (sps since we're interpolating by sps)
111 self._samples_per_symbol, # sampling rate
113 self._excess_bw, # excess bandwidth (roll-off factor)
116 self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
119 self._print_verbage()
122 self._setup_logging()
125 self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
126 self.chunks2symbols, self.rrc_filter, self)
128 def samples_per_symbol(self):
129 return self._samples_per_symbol
131 def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
133 bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
135 def _print_verbage(self):
136 print "bits per symbol = %d" % self.bits_per_symbol()
137 print "Gray code = %s" % self._gray_code
138 print "RRS roll-off factor = %f" % self._excess_bw
140 def _setup_logging(self):
141 print "Modulation logging turned on."
142 self.connect(self.bytes2chunks,
143 gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
144 self.connect(self.symbol_mapper,
145 gr.file_sink(gr.sizeof_char, "graycoder.dat"))
146 self.connect(self.diffenc,
147 gr.file_sink(gr.sizeof_char, "diffenc.dat"))
148 self.connect(self.chunks2symbols,
149 gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
150 self.connect(self.rrc_filter,
151 gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
153 def add_options(parser):
155 Adds QAM modulation-specific options to the standard parser
157 parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
158 help="set RRC excess bandwith factor [default=%default] (PSK)")
159 parser.add_option("", "--no-gray-code", dest="gray_code",
160 action="store_false", default=_def_gray_code,
161 help="disable gray coding on modulated bits (PSK)")
162 add_options=staticmethod(add_options)
165 def extract_kwargs_from_options(options):
167 Given command line options, create dictionary suitable for passing to __init__
169 return modulation_utils.extract_kwargs_from_options(qam64_mod.__init__,
171 extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
174 # /////////////////////////////////////////////////////////////////////////////
177 # /////////////////////////////////////////////////////////////////////////////
179 class qam64_demod(gr.hier_block2):
182 samples_per_symbol=_def_samples_per_symbol,
183 excess_bw=_def_excess_bw,
184 costas_alpha=_def_costas_alpha,
185 gain_mu=_def_gain_mu,
187 omega_relative_limit=_def_omega_relative_limit,
188 gray_code=_def_gray_code,
189 verbose=_def_verbose,
192 gr.hier_block2.__init__(self, "qam64_demod",
193 gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
194 gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
199 def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
201 bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
204 # Add these to the mod/demod registry
206 # NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
207 #modulation_utils.add_type_1_mod('qam64', qam64_mod)
208 #modulation_utils.add_type_1_demod('qam16', qam16_demod)