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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
#
# Copyright 2005,2006 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, gru, blks
from gnuradio import usrp
from gnuradio import eng_notation
import copy
import sys
# from current dir
from pick_bitrate import pick_tx_bitrate
# /////////////////////////////////////////////////////////////////////////////
# transmit path
# /////////////////////////////////////////////////////////////////////////////
class transmit_path(gr.hier_block):
def __init__(self, fg, modulator_class, options):
'''
See below for what options should hold
'''
options = copy.copy(options) # make a copy so we can destructively modify
self._verbose = options.verbose
self._tx_freq = options.tx_freq # tranmitter's center frequency
self._tx_amplitude = options.tx_amplitude # digital amplitude sent to USRP
self._tx_subdev_spec = options.tx_subdev_spec # daughterboard to use
self._bitrate = options.bitrate # desired bit rate
self._interp = options.interp # interpolating rate for the USRP (prelim)
self._samples_per_symbol = options.samples_per_symbol # desired samples/baud
self._fusb_block_size = options.fusb_block_size # usb info for USRP
self._fusb_nblocks = options.fusb_nblocks # usb info for USRP
self._use_whitener_offset = options.use_whitener_offset # increment start of whitener XOR data
self._modulator_class = modulator_class # the modulator_class we are using
if self._tx_freq is None:
sys.stderr.write("-f FREQ or --freq FREQ or --tx-freq FREQ must be specified\n")
raise SystemExit
# Set up USRP sink; also adjusts interp, samples_per_symbol, and bitrate
self._setup_usrp_sink()
# copy the final answers back into options for use by modulator
options.samples_per_symbol = self._samples_per_symbol
options.bitrate = self._bitrate
options.interp = self._interp
# Get mod_kwargs
mod_kwargs = self._modulator_class.extract_kwargs_from_options(options)
# Set center frequency of USRP
ok = self.set_freq(self._tx_freq)
if not ok:
print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(self._tx_freq),)
raise ValueError
# transmitter
self.packet_transmitter = \
blks.mod_pkts(fg,
self._modulator_class(fg, **mod_kwargs),
access_code=None,
msgq_limit=4,
pad_for_usrp=True,
use_whitener_offset=options.use_whitener_offset)
# Set the USRP for maximum transmit gain
# (Note that on the RFX cards this is a nop.)
self.set_gain(self.subdev.gain_range()[1])
self.amp = gr.multiply_const_cc(1)
self.set_tx_amplitude(self._tx_amplitude)
# enable Auto Transmit/Receive switching
self.set_auto_tr(True)
# Display some information about the setup
if self._verbose:
self._print_verbage()
# Create and setup transmit path flow graph
fg.connect(self.packet_transmitter, self.amp, self.u)
gr.hier_block.__init__(self, fg, None, None)
def _setup_usrp_sink(self):
"""
Creates a USRP sink, determines the settings for best bitrate,
and attaches to the transmitter's subdevice.
"""
self.u = usrp.sink_c(fusb_block_size=self._fusb_block_size,
fusb_nblocks=self._fusb_nblocks)
dac_rate = self.u.dac_rate();
# derive values of bitrate, samples_per_symbol, and interp from desired info
(self._bitrate, self._samples_per_symbol, self._interp) = \
pick_tx_bitrate(self._bitrate, self._modulator_class.bits_per_symbol(),
self._samples_per_symbol, self._interp, dac_rate)
self.u.set_interp_rate(self._interp)
# determine the daughterboard subdevice we're using
if self._tx_subdev_spec is None:
self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u)
self.u.set_mux(usrp.determine_tx_mux_value(self.u, self._tx_subdev_spec))
self.subdev = usrp.selected_subdev(self.u, self._tx_subdev_spec)
def set_freq(self, target_freq):
"""
Set the center frequency we're interested in.
@param target_freq: frequency in Hz
@rypte: 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 up converter.
"""
r = self.u.tune(self.subdev._which, self.subdev, target_freq)
if r:
return True
return False
def set_gain(self, gain):
"""
Sets the analog gain in the USRP
"""
self.gain = gain
self.subdev.set_gain(gain)
def set_tx_amplitude(self, ampl):
"""
Sets the transmit amplitude sent to the USRP
@param: ampl 0 <= ampl < 32768. Try 8000
"""
self._tx_amplitude = max(0.0, min(ampl, 32767.0))
self.amp.set_k(self._tx_amplitude)
def set_auto_tr(self, enable):
"""
Turns on auto transmit/receive of USRP daughterboard (if exits; else ignored)
"""
return self.subdev.set_auto_tr(enable)
def send_pkt(self, payload='', eof=False):
"""
Calls the transmitter method to send a packet
"""
return self.packet_transmitter.send_pkt(payload, eof)
def bitrate(self):
return self._bitrate
def samples_per_symbol(self):
return self._samples_per_symbol
def interp(self):
return self._interp
def add_options(normal, expert):
"""
Adds transmitter-specific options to the Options Parser
"""
add_freq_option(normal)
if not normal.has_option('--bitrate'):
normal.add_option("-r", "--bitrate", type="eng_float", default=None,
help="specify bitrate. samples-per-symbol and interp/decim will be derived.")
normal.add_option("-T", "--tx-subdev-spec", type="subdev", default=None,
help="select USRP Tx side A or B")
normal.add_option("", "--tx-amplitude", type="eng_float", default=12000, metavar="AMPL",
help="set transmitter digital amplitude: 0 <= AMPL < 32768 [default=%default]")
normal.add_option("-v", "--verbose", action="store_true", default=False)
expert.add_option("-S", "--samples-per-symbol", type="int", default=None,
help="set samples/symbol [default=%default]")
expert.add_option("", "--tx-freq", type="eng_float", default=None,
help="set transmit frequency to FREQ [default=%default]", metavar="FREQ")
expert.add_option("-i", "--interp", type="intx", default=None,
help="set fpga interpolation rate to INTERP [default=%default]")
expert.add_option("", "--log", action="store_true", default=False,
help="Log all parts of flow graph to file (CAUTION: lots of data)")
expert.add_option("","--use-whitener-offset", action="store_true", default=False,
help="make sequential packets use different whitening")
# Make a static method to call before instantiation
add_options = staticmethod(add_options)
def _print_verbage(self):
"""
Prints information about the transmit path
"""
print "Using TX d'board %s" % (self.subdev.side_and_name(),)
print "Tx amplitude %s" % (self._tx_amplitude)
print "modulation: %s" % (self._modulator_class.__name__)
print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate))
print "samples/symbol: %3d" % (self._samples_per_symbol)
print "interp: %3d" % (self._interp)
print "Tx Frequency: %s" % (eng_notation.num_to_str(self._tx_freq))
def add_freq_option(parser):
"""
Hackery that has the -f / --freq option set both tx_freq and rx_freq
"""
def freq_callback(option, opt_str, value, parser):
parser.values.rx_freq = value
parser.values.tx_freq = value
if not parser.has_option('--freq'):
parser.add_option('-f', '--freq', type="eng_float",
action="callback", callback=freq_callback,
help="set Tx and/or Rx frequency to FREQ [default=%default]",
metavar="FREQ")
|
