Imported Upstream version 3.2.2

[debian/gnuradio] / gnuradio-core / src / python / gnuradio / blks2impl / wfm_rcv.py

diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv.py b/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv.py
new file mode 100644 (file)
index 0000000..3bdb22c
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/wfm_rcv.py
@@ -0,0 +1,69 @@
+#
+# Copyright 2005,2007 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
+from gnuradio.blks2impl.fm_emph import fm_deemph
+import math
+
+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).
+        
+        @param quad_rate: input sample rate of complex baseband input.
+        @type quad_rate: float
+        @param audio_decimation: how much to decimate quad_rate to get to audio.
+        @type audio_decimation: 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 = gr.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 = gr.firdes.low_pass (1.0,         # gain
+                                           quad_rate,      # sampling rate
+                                           audio_rate/2 - width_of_transition_band,
+                                           width_of_transition_band,
+                                           gr.firdes.WIN_HAMMING)
+        # input: float; output: float
+        self.audio_filter = gr.fir_filter_fff (audio_decimation, audio_coeffs)
+
+        self.connect (self, self.fm_demod, self.audio_filter, self.deemph, self)