From 5d69a524f81f234b3fbc41d49ba18d6f6886baba Mon Sep 17 00:00:00 2001
From: jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Thu, 3 Aug 2006 04:51:51 +0000
Subject: Houston, we have a trunk.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5
---
gnuradio-examples/python/audio/dial_squelch.py | 89 ++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
create mode 100755 gnuradio-examples/python/audio/dial_squelch.py
(limited to 'gnuradio-examples/python/audio/dial_squelch.py')
diff --git a/gnuradio-examples/python/audio/dial_squelch.py b/gnuradio-examples/python/audio/dial_squelch.py
new file mode 100755
index 0000000000..d947e58604
--- /dev/null
+++ b/gnuradio-examples/python/audio/dial_squelch.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python
+
+# Copyright 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., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+#
+
+from gnuradio import gr, audio, eng_option
+from gnuradio.eng_option import eng_option
+from math import pi, cos
+from optparse import OptionParser
+
+"""
+This script generates a standard dial tone and then applies a sinusoidal
+envelope to vary it's loudness. The audio is then passed through the
+power squelch block before it gets sent to the sound card. By varying
+the command line parameters, one can see the effect of differing
+amounts of power averaging, threshold, and attack/decay ramping.
+"""
+
+class app_flow_graph(gr.flow_graph):
+ def __init__(self, options, args):
+ gr.flow_graph.__init__(self)
+
+ # Create dial tone by adding two sine waves
+ SRC1 = gr.sig_source_f(options.rate, gr.GR_SIN_WAVE, 350, 0.5, 0.0)
+ SRC2 = gr.sig_source_f(options.rate, gr.GR_SIN_WAVE, 440, 0.5, 0.0)
+ ADD = gr.add_ff()
+
+ # Convert to vector stream (and back) to apply raised cosine envelope
+ # You could also do this with a vector_source_f block that repeats.
+ S2V = gr.stream_to_vector(gr.sizeof_float, options.rate)
+ ENV = [0.5-cos(2*pi*x/options.rate)/2 for x in range(options.rate)]
+ MLT = gr.multiply_const_vff(ENV)
+ V2S = gr.vector_to_stream(gr.sizeof_float, options.rate)
+
+ # Run through power squelch with user supplied or default options
+ # Zero output when squelch is invoked
+ SQL = gr.pwr_squelch_ff(options.threshold, options.alpha, options.ramp, False)
+ DST = audio.sink(options.rate)
+
+ # Solder it all together
+ self.connect(SRC1, (ADD, 0))
+ self.connect(SRC2, (ADD, 1))
+ self.connect(ADD, S2V, MLT, V2S, SQL, DST)
+
+def main():
+ parser = OptionParser(option_class=eng_option)
+ parser.add_option("-r", "--rate", type="int", default=8000, help="set audio output sample rate to RATE", metavar="RATE")
+ parser.add_option("-t", "--threshold", type="eng_float", default=-10.0, help="set power squelch to DB", metavar="DB")
+ parser.add_option("-a", "--alpha", type="eng_float", default=None, help="set alpha to ALPHA", metavar="ALPHA")
+ parser.add_option("-m", "--ramp", type="int", default=None, help="set attack/decay ramp to SAMPLES", metavar="SAMPLES")
+ (options, args) = parser.parse_args()
+
+ if options.alpha == None:
+ options.alpha = 50.0/options.rate
+
+ if options.ramp == None:
+ options.ramp = options.rate/50 # ~ 20 ms
+
+ print "Using audio rate of", options.rate
+ print "Using threshold of", options.threshold, "db"
+ print "Using alpha of", options.alpha
+ print "Using ramp of", options.ramp, "samples"
+
+ fg = app_flow_graph(options, args)
+
+ try:
+ fg.run()
+ except KeyboardInterrupt:
+ pass
+
+if __name__ == "__main__":
+ main()
--
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