From 43819f0f33498239970b4479684f12aa080859e6 Mon Sep 17 00:00:00 2001
From: jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Thu, 26 Apr 2007 22:51:48 +0000
Subject: Merged r4518:5130 from developer branch n4hy/ofdm into trunk, passes
distcheck.
Adds incomplete OFDM implementation, further work to be completed in the
features/ofdm branch.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@5131 221aa14e-8319-0410-a670-987f0aec2ac5
---
gnuradio-examples/python/ofdm/receive_path.py | 125 ++++++++++++++++++++++++++
1 file changed, 125 insertions(+)
create mode 100644 gnuradio-examples/python/ofdm/receive_path.py
(limited to 'gnuradio-examples/python/ofdm/receive_path.py')
diff --git a/gnuradio-examples/python/ofdm/receive_path.py b/gnuradio-examples/python/ofdm/receive_path.py
new file mode 100644
index 0000000000..1c9c23844c
--- /dev/null
+++ b/gnuradio-examples/python/ofdm/receive_path.py
@@ -0,0 +1,125 @@
+#!/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 usrp
+from gnuradio import eng_notation
+import copy
+import sys
+
+# from current dir
+from pick_bitrate import pick_rx_bitrate
+import ofdm
+
+# /////////////////////////////////////////////////////////////////////////////
+# receive path
+# /////////////////////////////////////////////////////////////////////////////
+
+class receive_path(gr.hier_block):
+ def __init__(self, fg, rx_callback, options):
+
+ options = copy.copy(options) # make a copy so we can destructively modify
+
+ self._verbose = options.verbose
+ self._log = options.log
+ self._rx_callback = rx_callback # this callback is fired when there's a packet available
+
+ if 0:
+
+ chan_coeffs = gr.firdes.low_pass (1.0, # gain
+ 2.0, # sampling rate
+ bw, # midpoint of trans. band
+ 1*bw, # width of trans. band
+ gr.firdes.WIN_KAISER) # filter type
+ else:
+ chan_coeffs = [ 1.0, 0.0, 0 ]
+ self.chan_filt = gr.fft_filter_ccc(1, chan_coeffs)
+
+ self.ofdm_demod = ofdm.ofdm_demod(fg, options)
+
+ # receiver
+ self.packet_receiver = \
+ blks.demod_ofdm_pkts(fg,
+ self.ofdm_demod,
+ 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)
+ fg.connect(self.chan_filt, self.probe)
+
+ # Display some information about the setup
+ if self._verbose:
+ self._print_verbage()
+
+ fg.connect(self.chan_filt, self.packet_receiver)
+ #fg.connect(self.chan_filt, gr.file_sink(gr.sizeof_gr_complex, "ofdmrx_chflt.dat"))
+ gr.hier_block.__init__(self, fg, self.chan_filt, None)
+
+ 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
+ """
+ normal.add_option("-v", "--verbose", action="store_true", default=False)
+ 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 "Using RX d'board %s" % (self.subdev.side_and_name(),)
+ print "Rx gain: %g" % (self.gain,)
+ 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)
+ print "decim: %3d" % (self._decim)
--
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