From 317e8321472cb9e921757636b561897b12199195 Mon Sep 17 00:00:00 2001
From: Tom Rondeau
Date: Tue, 30 Aug 2011 16:35:30 -0400
Subject: digital: adding a script to add channel conditions to a saved file
 and output to another file.

---
 gr-digital/examples/benchmark_add_channel.py | 101 +++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100755 gr-digital/examples/benchmark_add_channel.py

(limited to 'gr-digital/examples/benchmark_add_channel.py')

diff --git a/gr-digital/examples/benchmark_add_channel.py b/gr-digital/examples/benchmark_add_channel.py
new file mode 100755
index 000000000..def1f8267
--- /dev/null
+++ b/gr-digital/examples/benchmark_add_channel.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+#
+# Copyright 2010,2011 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.
+# 
+
+from gnuradio import gr
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random, math, sys
+
+class my_top_block(gr.top_block):
+    def __init__(self, ifile, ofile, options):
+        gr.top_block.__init__(self)
+
+        SNR = 10.0**(options.snr/10.0)
+        frequency_offset = options.frequency_offset
+        time_offset = options.time_offset
+        phase_offset = options.phase_offset*(math.pi/180.0)
+
+        # calculate noise voltage from SNR
+        # FIXME: normalize to signal amplitude
+        power_in_signal = abs(1.0)**2
+        noise_power = power_in_signal/SNR
+        noise_voltage = math.sqrt(noise_power)
+        print noise_voltage
+
+        self.src = gr.file_source(gr.sizeof_gr_complex, ifile)
+        #self.throttle = gr.throttle(gr.sizeof_gr_complex, options.sample_rate)
+        self.channel = gr.channel_model(noise_voltage, frequency_offset,
+                                        time_offset, noise_seed=random.randint(0,100000))
+        self.phase = gr.multiply_const_cc(complex(math.cos(phase_offset),
+                                                  math.sin(phase_offset)))
+        self.snk = gr.file_sink(gr.sizeof_gr_complex, ofile)
+
+        self.connect(self.src, self.channel, self.phase, self.snk)
+        
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+def main():
+    # Create Options Parser:
+    usage = "benchmack_add_channel.py [options] <input file> <output file>"
+    parser = OptionParser (usage=usage, option_class=eng_option, conflict_handler="resolve")
+    parser.add_option("-n", "--snr", type="eng_float", default=30,
+                      help="set the SNR of the channel in dB [default=%default]")
+    parser.add_option("", "--seed", action="store_true", default=False,
+                      help="use a random seed for AWGN noise [default=%default]")
+    parser.add_option("-f", "--frequency-offset", type="eng_float", default=0,
+                      help="set frequency offset introduced by channel [default=%default]")
+    parser.add_option("-t", "--time-offset", type="eng_float", default=1.0,
+                      help="set timing offset between Tx and Rx [default=%default]")
+    parser.add_option("-p", "--phase-offset", type="eng_float", default=0,
+                      help="set phase offset (in degrees) between Tx and Rx [default=%default]")
+    parser.add_option("-m", "--use-multipath", action="store_true", default=False,
+                      help="Use a multipath channel [default=%default]")
+
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 2:
+        parser.print_help(sys.stderr)
+        sys.exit(1)
+
+    ifile = args[0]
+    ofile = args[1]
+        
+    # build the graph
+    tb = my_top_block(ifile, ofile, options)
+
+    r = gr.enable_realtime_scheduling()
+    if r != gr.RT_OK:
+        print "Warning: Failed to enable realtime scheduling."
+
+    tb.start()        # start flow graph
+    tb.wait()         # wait for it to finish
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
-- 
cgit