Imported Upstream version 3.2.2

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

diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/fm_demod.py b/gnuradio-core/src/python/gnuradio/blks2impl/fm_demod.py
new file mode 100644 (file)
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+++ b/gnuradio-core/src/python/gnuradio/blks2impl/fm_demod.py
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+#
+# Copyright 2006,2007 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, optfir
+from gnuradio.blks2impl.fm_emph import fm_deemph
+from math import pi
+
+class fm_demod_cf(gr.hier_block2):
+    """
+    Generalized FM demodulation block with deemphasis and audio 
+    filtering.
+
+    This block demodulates a band-limited, complex down-converted FM 
+    channel into the the original baseband signal, optionally applying
+    deemphasis. Low pass filtering is done on the resultant signal. It
+    produces an output float strem in the range of [-1.0, +1.0].
+
+    @param channel_rate:  incoming sample rate of the FM baseband
+    @type sample_rate: integer
+    @param deviation: maximum FM deviation (default = 5000)
+    @type deviation: float
+    @param audio_decim: input to output decimation rate
+    @type audio_decim: integer
+    @param audio_pass: audio low pass filter passband frequency 
+    @type audio_pass: float
+    @param audio_stop: audio low pass filter stop frequency
+    @type audio_stop: float
+    @param gain: gain applied to audio output (default = 1.0)
+    @type gain: float
+    @param tau: deemphasis time constant (default = 75e-6), specify 'None'
+       to prevent deemphasis
+    """ 
+    def __init__(self, channel_rate, audio_decim, deviation, 
+                 audio_pass, audio_stop, gain=1.0, tau=75e-6):
+       gr.hier_block2.__init__(self, "fm_demod_cf",
+                               gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+                               gr.io_signature(1, 1, gr.sizeof_float))      # Output signature
+                               
+       k = channel_rate/(2*pi*deviation)
+       QUAD = gr.quadrature_demod_cf(k)
+
+       audio_taps = optfir.low_pass(gain,         # Filter gain
+                                    channel_rate, # Sample rate
+                                    audio_pass,   # Audio passband
+                                    audio_stop,   # Audio stopband
+                                    0.1,          # Passband ripple
+                                    60)           # Stopband attenuation
+       LPF = gr.fir_filter_fff(audio_decim, audio_taps)
+
+       if tau is not None:
+           DEEMPH = fm_deemph(channel_rate, tau)
+           self.connect(self, QUAD, DEEMPH, LPF, self)
+        else:
+            self.connect(self, QUAD, LPF, self)
+
+class demod_20k0f3e_cf(fm_demod_cf):
+    """
+    NBFM demodulation block, 20 KHz channels
+
+    This block demodulates a complex, downconverted, narrowband FM 
+    channel conforming to 20K0F3E emission standards, outputting
+    floats in the range [-1.0, +1.0].
+    
+    @param sample_rate:  incoming sample rate of the FM baseband
+    @type sample_rate: integer
+    @param audio_decim: input to output decimation rate
+    @type audio_decim: integer
+    """ 
+    def __init__(self, channel_rate, audio_decim):
+        fm_demod_cf.__init__(self, channel_rate, audio_decim,
+                             5000,     # Deviation
+                             3000,     # Audio passband frequency
+                             4000)     # Audio stopband frequency
+
+class demod_200kf3e_cf(fm_demod_cf):
+    """
+    WFM demodulation block, mono.
+    
+    This block demodulates a complex, downconverted, wideband FM 
+    channel conforming to 200KF3E emission standards, outputting 
+    floats in the range [-1.0, +1.0].
+
+    @param sample_rate:  incoming sample rate of the FM baseband
+    @type sample_rate: integer
+    @param audio_decim: input to output decimation rate
+    @type audio_decim: integer
+    """
+    def __init__(self, channel_rate, audio_decim): 
+       fm_demod_cf.__init__(self, channel_rate, audio_decim,
+                            75000,     # Deviation
+                            15000,     # Audio passband
+                            16000,     # Audio stopband
+                            20.0)      # Audio gain