From 28e086141aead2e43f958f0ae14d58cac557fa2d Mon Sep 17 00:00:00 2001
From: trondeau <trondeau@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Wed, 7 Mar 2007 04:31:19 +0000
Subject: merged trondeau/digital-wip2 r4193:4730 into trunk - improves digital
receiver and fixes ticket:72
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@4731 221aa14e-8319-0410-a670-987f0aec2ac5
---
.../python/digital/receive_path_lb.py | 136 +++++++++++++++++++++
1 file changed, 136 insertions(+)
create mode 100644 gnuradio-examples/python/digital/receive_path_lb.py
(limited to 'gnuradio-examples/python/digital/receive_path_lb.py')
diff --git a/gnuradio-examples/python/digital/receive_path_lb.py b/gnuradio-examples/python/digital/receive_path_lb.py
new file mode 100644
index 0000000000..2bfdd72d44
--- /dev/null
+++ b/gnuradio-examples/python/digital/receive_path_lb.py
@@ -0,0 +1,136 @@
+#!/usr/bin/env python
+#
+# 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 eng_notation
+import copy
+import sys
+
+# /////////////////////////////////////////////////////////////////////////////
+# receive path
+# /////////////////////////////////////////////////////////////////////////////
+
+class receive_path(gr.hier_block):
+ def __init__(self, fg, demod_class, rx_callback, options):
+
+ options = copy.copy(options) # make a copy so we can destructively modify
+
+ self._verbose = options.verbose
+ self._bitrate = options.bitrate # desired bit rate
+ self._samples_per_symbol = options.samples_per_symbol # desired samples/symbol
+
+ self._rx_callback = rx_callback # this callback is fired when there's a packet available
+ self._demod_class = demod_class # the demodulator_class we're using
+
+ # Get demod_kwargs
+ demod_kwargs = self._demod_class.extract_kwargs_from_options(options)
+
+ # Design filter to get actual channel we want
+ sw_decim = 1
+ chan_coeffs = gr.firdes.low_pass (1.0, # gain
+ sw_decim * self._samples_per_symbol, # sampling rate
+ 1.0, # midpoint of trans. band
+ 0.5, # width of trans. band
+ gr.firdes.WIN_HANN) # filter type
+ self.channel_filter = gr.fft_filter_ccc(sw_decim, chan_coeffs)
+
+ # receiver
+ self.packet_receiver = \
+ blks.demod_pkts(fg,
+ self._demod_class(fg, **demod_kwargs),
+ access_code=None,
+ callback=self._rx_callback,
+ threshold=-1)
+
+ # Carrier Sensing Blocks
+ alpha = 0.001
+ thresh = 30 # in dB, will have to adjust
+ self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
+
+ # Display some information about the setup
+ if self._verbose:
+ self._print_verbage()
+
+ # connect the channel input filter to the carrier power detector
+ fg.connect(self.channel_filter, self.probe)
+
+ # connect channel filter to the packet receiver
+ fg.connect(self.channel_filter, self.packet_receiver)
+
+ gr.hier_block.__init__(self, fg, self.channel_filter, None)
+
+ def bitrate(self):
+ return self._bitrate
+
+ def samples_per_symbol(self):
+ return self._samples_per_symbol
+
+ def carrier_sensed(self):
+ """
+ Return True if we think carrier is present.
+ """
+ #return self.probe.level() > X
+ return self.probe.unmuted()
+
+ def carrier_threshold(self):
+ """
+ Return current setting in dB.
+ """
+ return self.probe.threshold()
+
+ def set_carrier_threshold(self, threshold_in_db):
+ """
+ Set carrier threshold.
+
+ @param threshold_in_db: set detection threshold
+ @type threshold_in_db: float (dB)
+ """
+ self.probe.set_threshold(threshold_in_db)
+
+
+ def add_options(normal, expert):
+ """
+ Adds receiver-specific options to the Options Parser
+ """
+ if not normal.has_option("--bitrate"):
+ normal.add_option("-r", "--bitrate", type="eng_float", default=100e3,
+ help="specify bitrate [default=%default].")
+ normal.add_option("", "--show-rx-gain-range", action="store_true", default=False,
+ help="print min and max Rx gain available on selected daughterboard")
+ normal.add_option("-v", "--verbose", action="store_true", default=False)
+ expert.add_option("-S", "--samples-per-symbol", type="int", default=2,
+ help="set samples/symbol [default=%default]")
+ expert.add_option("", "--log", action="store_true", default=False,
+ help="Log all parts of flow graph to files (CAUTION: lots of data)")
+
+ # Make a static method to call before instantiation
+ add_options = staticmethod(add_options)
+
+
+ def _print_verbage(self):
+ """
+ Prints information about the receive path
+ """
+ print "\nReceive Path:"
+ print "modulation: %s" % (self._demod_class.__name__)
+ print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate))
+ print "samples/symbol: %3d" % (self._samples_per_symbol)
--
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