1 files changed, 73 insertions, 0 deletions
diff --git a/gr-analog/python/analog/wfm_rcv.py b/gr-analog/python/analog/wfm_rcv.py
new file mode 100644
index 0000000000..d35d219275
--- /dev/null
+++ b/gr-analog/python/analog/wfm_rcv.py
@@ -0,0 +1,73 @@
+#
+# Copyright 2005,2007,2012 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 3, 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, filter
+from fm_emph import fm_deemph
+import math
+
+try:
+    from gnuradio import analog
+except ImportError:
+    import analog_swig as analog
+
+class wfm_rcv(gr.hier_block2):
+    def __init__ (self, quad_rate, audio_decimation):
+        """
+        Hierarchical block for demodulating a broadcast FM signal.
+
+        The input is the downconverted complex baseband signal (gr_complex).
+        The output is the demodulated audio (float).
+
+        Args:
+            quad_rate: input sample rate of complex baseband input. (float)
+            audio_decimation: how much to decimate quad_rate to get to audio. (integer)
+        """
+	gr.hier_block2.__init__(self, "wfm_rcv",
+				gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+				gr.io_signature(1, 1, gr.sizeof_float))      # Output signature
+
+        volume = 20.
+
+        max_dev = 75e3
+        fm_demod_gain = quad_rate/(2*math.pi*max_dev)
+        audio_rate = quad_rate / audio_decimation
+
+
+        # We assign to self so that outsiders can grab the demodulator
+        # if they need to.  E.g., to plot its output.
+        #
+        # input: complex; output: float
+        self.fm_demod = analog.quadrature_demod_cf(fm_demod_gain)
+
+        # input: float; output: float
+        self.deemph = fm_deemph(audio_rate)
+
+        # compute FIR filter taps for audio filter
+        width_of_transition_band = audio_rate / 32
+        audio_coeffs = filter.firdes.low_pass(1.0,            # gain
+                                              quad_rate,      # sampling rate
+                                              audio_rate/2 - width_of_transition_band,
+                                              width_of_transition_band,
+                                              filter.firdes.WIN_HAMMING)
+        # input: float; output: float
+        self.audio_filter = filter.fir_filter_fff(audio_decimation, audio_coeffs)
+
+        self.connect (self, self.fm_demod, self.audio_filter, self.deemph, self)