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, 264 insertions, 0 deletions

diff --git a/gnuradio-examples/python/hier/digital/receive_path.py b/gnuradio-examples/python/hier/digital/receive_path.py
new file mode 100644
index 000000000..64a547dce
--- /dev/null
+++ b/gnuradio-examples/python/hier/digital/receive_path.py
@@ -0,0 +1,264 @@
+#!/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 usrp
+from gnuradio import eng_notation
+import copy
+import sys
+
+# from current dir
+from pick_bitrate import pick_rx_bitrate
+
+# /////////////////////////////////////////////////////////////////////////////
+#                              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(0,0,0), # 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._rx_freq            = options.rx_freq         # receiver's center frequency
+        self._rx_gain            = options.rx_gain         # receiver's gain
+        self._rx_subdev_spec     = options.rx_subdev_spec  # daughterboard to use
+        self._bitrate            = options.bitrate         # desired bit rate
+        self._decim              = options.decim           # Decimating rate for the USRP (prelim)
+        self._samples_per_symbol = options.samples_per_symbol  # desired samples/symbol
+        self._fusb_block_size    = options.fusb_block_size # usb info for USRP
+        self._fusb_nblocks       = options.fusb_nblocks    # usb info for USRP
+
+        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
+
+        if self._rx_freq is None:
+            sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ must be specified\n")
+            raise SystemExit
+
+        # Set up USRP source; also adjusts decim, samples_per_symbol, and bitrate
+        self._setup_usrp_source()
+
+        g = self.subdev.gain_range()
+        if options.show_rx_gain_range:
+            print "Rx Gain Range: minimum = %g, maximum = %g, step size = %g" \
+                  % (g[0], g[1], g[2])
+
+        self.set_gain(options.rx_gain)
+
+        self.set_auto_tr(True)                 # enable Auto Transmit/Receive switching
+
+        # Set RF frequency
+        ok = self.set_freq(self._rx_freq)
+        if not ok:
+            print "Failed to set Rx frequency to %s" % (eng_notation.num_to_str(self._rx_freq))
+            raise ValueError, eng_notation.num_to_str(self._rx_freq)
+
+        # copy the final answers back into options for use by demodulator
+        options.samples_per_symbol = self._samples_per_symbol
+        options.bitrate = self._bitrate
+        options.decim = self._decim
+
+        # 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 
+
+        # Decimating channel filter
+        # complex in and out, float taps
+        self.chan_filt = gr.fft_filter_ccc(sw_decim, chan_coeffs)
+        #self.chan_filt = gr.fir_filter_ccf(sw_decim, chan_coeffs)
+        # 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("usrp", self.u)
+        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("usrp", 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 _setup_usrp_source(self):
+        self.u = usrp.source_c (fusb_block_size=self._fusb_block_size,
+                                fusb_nblocks=self._fusb_nblocks)
+        adc_rate = self.u.adc_rate()
+
+        # derive values of bitrate, samples_per_symbol, and decim from desired info
+        (self._bitrate, self._samples_per_symbol, self._decim) = \
+            pick_rx_bitrate(self._bitrate, self._demod_class.bits_per_symbol(), \
+                            self._samples_per_symbol, self._decim, adc_rate)
+
+        self.u.set_decim_rate(self._decim)
+
+        # determine the daughterboard subdevice we're using
+        if self._rx_subdev_spec is None:
+            self._rx_subdev_spec = usrp.pick_rx_subdevice(self.u)
+        self.subdev = usrp.selected_subdev(self.u, self._rx_subdev_spec)
+
+        self.u.set_mux(usrp.determine_rx_mux_value(self.u, self._rx_subdev_spec))
+
+    def set_freq(self, target_freq):
+        """
+        Set the center frequency we're interested in.
+
+        @param target_freq: frequency in Hz
+        @rypte: bool
+
+        Tuning is a two step process.  First we ask the front-end to
+        tune as close to the desired frequency as it can.  Then we use
+        the result of that operation and our target_frequency to
+        determine the value for the digital up converter.
+        """
+        r = self.u.tune(0, self.subdev, target_freq)
+        if r:
+            return True
+
+        return False
+
+    def set_gain(self, gain):
+        """
+        Sets the analog gain in the USRP
+        """
+        if gain is None:
+            r = self.subdev.gain_range()
+            gain = (r[0] + r[1])/2               # set gain to midpoint
+        self.gain = gain
+        return self.subdev.set_gain(gain)
+
+    def set_auto_tr(self, enable):
+        return self.subdev.set_auto_tr(enable)
+        
+    def bitrate(self):
+        return self._bitrate
+
+    def samples_per_symbol(self):
+        return self._samples_per_symbol
+
+    def decim(self):
+        return self._decim
+
+    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
+        """
+        add_freq_option(normal)
+        if not normal.has_option("--bitrate"):
+            normal.add_option("-r", "--bitrate", type="eng_float", default=None,
+                              help="specify bitrate.  samples-per-symbol and interp/decim will be derived.")
+        normal.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
+                          help="select USRP Rx side A or B")
+        normal.add_option("", "--rx-gain", type="eng_float", default=None, metavar="GAIN",
+                          help="set receiver gain in dB [default=midpoint].  See also --show-rx-gain-range")
+        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=None,
+                          help="set samples/symbol [default=%default]")
+        expert.add_option("", "--rx-freq", type="eng_float", default=None,
+                          help="set Rx frequency to FREQ [default=%default]", metavar="FREQ")
+        expert.add_option("-d", "--decim", type="intx", default=None,
+                          help="set fpga decimation rate to DECIM [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 "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)
+        print "Rx Frequency:    %s"    % (eng_notation.num_to_str(self._rx_freq))
+
+def add_freq_option(parser):
+    """
+    Hackery that has the -f / --freq option set both tx_freq and rx_freq
+    """
+    def freq_callback(option, opt_str, value, parser):
+        parser.values.rx_freq = value
+        parser.values.tx_freq = value
+
+    if not parser.has_option('--freq'):
+        parser.add_option('-f', '--freq', type="eng_float",
+                          action="callback", callback=freq_callback,
+                          help="set Tx and/or Rx frequency to FREQ [default=%default]",
+                          metavar="FREQ")