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

1 files changed, 140 insertions, 0 deletions

diff --git a/gnuradio-examples/python/hier/digital/receive_path_lb.py b/gnuradio-examples/python/hier/digital/receive_path_lb.py
new file mode 100644
index 000000000..fada441ff
--- /dev/null
+++ b/gnuradio-examples/python/hier/digital/receive_path_lb.py
@@ -0,0 +1,140 @@
+#!/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, blks2
+from gnuradio import eng_notation
+import copy
+import sys
+
+# /////////////////////////////////////////////////////////////////////////////
+#                              receive path
+# /////////////////////////////////////////////////////////////////////////////
+
+class receive_path(gr.hier_block2):
+    def __init__(self, demod_class, rx_callback, options):
+        gr.hier_block2.__init__(self, "receive_path",
+                                gr.io_signature(1,1,gr.sizeof_gr_complex), # Input signature
+                                gr.io_signature(0,0,0))                    # Output signature
+
+        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 
+
+        # receiver
+        self.packet_receiver = \
+            blks2.demod_pkts(self._demod_class(**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()
+
+        # Define the components
+        self.define_component("channel_filter", gr.fft_filter_ccc(sw_decim, chan_coeffs))
+        self.define_component("channel_probe", self.probe)
+        self.define_component("packet_receiver", self.packet_receiver)
+
+        # connect the channel input filter to the carrier power detector
+        self.connect("self", 0, "channel_filter", 0)
+        self.connect("channel_filter", 0, "channel_probe", 0)
+
+        # connect channel filter to the packet receiver
+        self.connect("channel_filter", 0, "packet_receiver", 0)
+        
+    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 "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)