1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
#
# 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 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.
#
# See gnuradio-examples/python/digital for examples
"""
QAM8 modulation and demodulation.
"""
from gnuradio import gr, gru, modulation_utils
from math import pi, sqrt
import qam
import cmath
from pprint import pprint
# default values (used in __init__ and add_options)
_def_samples_per_symbol = 2
_def_excess_bw = 0.35
_def_gray_code = True
_def_verbose = False
_def_log = False
_def_costas_alpha = None
_def_gain_mu = 0.03
_def_mu = 0.05
_def_omega_relative_limit = 0.005
# /////////////////////////////////////////////////////////////////////////////
# QAM8 modulator
# /////////////////////////////////////////////////////////////////////////////
class qam8_mod(gr.hier_block2):
def __init__(self,
samples_per_symbol=_def_samples_per_symbol,
excess_bw=_def_excess_bw,
gray_code=_def_gray_code,
verbose=_def_verbose,
log=_def_log):
"""
Hierarchical block for RRC-filtered QPSK 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 symbol >= 2
@type samples_per_symbol: integer
@param excess_bw: Root-raised cosine filter excess bandwidth
@type excess_bw: float
@param gray_code: Tell modulator to Gray code the bits
@type gray_code: bool
@param verbose: Print information about modulator?
@type verbose: bool
@param debug: Print modualtion data to files?
@type debug: bool
"""
gr.hier_block2.__init__(self, "qam8_mod",
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._excess_bw = excess_bw
self._gray_code = gray_code
if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
ntaps = 11 * samples_per_symbol
arity = pow(2, self.bits_per_symbol())
# turn bytes into k-bit vectors
self.bytes2chunks = \
gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
if self._gray_code:
self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
else:
self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
self.diffenc = gr.diff_encoder_bb(arity)
rot = 1.0
print "constellation with %d arity" % arity
rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
# pulse shaping filter
self.rrc_taps = gr.firdes.root_raised_cosine(
self._samples_per_symbol, # gain (sps since we're interpolating by sps)
self._samples_per_symbol, # sampling rate
1.0, # symbol rate
self._excess_bw, # excess bandwidth (roll-off factor)
ntaps)
self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
if verbose:
self._print_verbage()
if log:
self._setup_logging()
# Connect
self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
self.chunks2symbols, self.rrc_filter, self)
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 3
bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
def _print_verbage(self):
print "bits per symbol = %d" % self.bits_per_symbol()
print "Gray code = %s" % self._gray_code
print "RRS roll-off factor = %f" % self._excess_bw
def _setup_logging(self):
print "Modulation logging turned on."
self.connect(self.bytes2chunks,
gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
self.connect(self.symbol_mapper,
gr.file_sink(gr.sizeof_char, "graycoder.dat"))
self.connect(self.diffenc,
gr.file_sink(gr.sizeof_char, "diffenc.dat"))
self.connect(self.chunks2symbols,
gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
self.connect(self.rrc_filter,
gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
def add_options(parser):
"""
Adds QAM modulation-specific options to the standard parser
"""
parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
help="set RRC excess bandwith factor [default=%default] (PSK)")
parser.add_option("", "--no-gray-code", dest="gray_code",
action="store_false", default=_def_gray_code,
help="disable gray coding on modulated bits (PSK)")
add_options=staticmethod(add_options)
def extract_kwargs_from_options(options):
"""
Given command line options, create dictionary suitable for passing to __init__
"""
return modulation_utils.extract_kwargs_from_options(qam8_mod.__init__,
('self',), options)
extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
# /////////////////////////////////////////////////////////////////////////////
# QAM8 demodulator
#
# /////////////////////////////////////////////////////////////////////////////
class qam8_demod(gr.hier_block2):
def __init__(self,
samples_per_symbol=_def_samples_per_symbol,
excess_bw=_def_excess_bw,
costas_alpha=_def_costas_alpha,
gain_mu=_def_gain_mu,
mu=_def_mu,
omega_relative_limit=_def_omega_relative_limit,
gray_code=_def_gray_code,
verbose=_def_verbose,
log=_def_log):
gr.hier_block2.__init__(self, "qam8_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
# do this
pass
def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
return 3
bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
#
# Add these to the mod/demod registry
#
# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
modulation_utils.add_type_1_mod('qam8', qam8_mod)
#modulation_utils.add_type_1_demod('qam8', qam8_demod)
|
