X-Git-Url: https://git.gag.com/?a=blobdiff_plain;ds=sidebyside;f=gnuradio-core%2Fsrc%2Fpython%2Fgnuradio%2Fblks2impl%2Fdigital_voice.py.real;fp=gnuradio-core%2Fsrc%2Fpython%2Fgnuradio%2Fblks2impl%2Fdigital_voice.py.real;h=6ec66825c17a2f5269a4fa2edc9e2180ffce4d46;hb=fd9980f919b6f05e2fbea404fea322825ce438f0;hp=0000000000000000000000000000000000000000;hpb=2415ccdbf9d97878a0888bbdff30d699ae2326dd;p=debian%2Fgnuradio

diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/digital_voice.py.real b/gnuradio-core/src/python/gnuradio/blks2impl/digital_voice.py.real
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+++ b/gnuradio-core/src/python/gnuradio/blks2impl/digital_voice.py.real
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+#!/usr/bin/env python
+#
+# Copyright 2005 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.
+# 
+
+"""
+Digital voice Tx and Rx using GSM 13kbit vocoder and GMSK.
+
+Runs channel at 32kbit/sec.  Currently uses fake channel coding,
+but there's room for a rate 1/2 coder.
+"""
+
+from gnuradio import gr, gru
+from gnuradio.blksimpl.gmsk import gmsk_mod, gmsk_demod
+
+from gnuradio.vocoder import gsm_full_rate
+
+# Size of gsm full rate speech encoder output packet in bytes
+
+GSM_FRAME_SIZE = 33
+
+# Size of packet in bytes that we send to GMSK modulator:
+#
+# Target: 256kS/sec air rate.
+#
+#  256kS  1 sym   1 bit   1 byte   0.020 sec   80 bytes
+#  ---- * ----- * ----- * ------ * --------- = --------
+#  sec    8 S     1 sym   8 bits     frame      frame
+#
+# gr_simple_framer add 10 bytes of overhead.
+
+AIR_FRAME_SIZE = 70
+
+
+class digital_voice_tx(gr.hier_block):
+    """
+    Hierarchical block for digital voice tranmission.
+
+    The input is 8kS/sec floating point audio in the range [-1,+1]
+    The output is 256kS/sec GMSK modulated complex baseband signal in the range [-1,+1].
+    """
+    def __init__(self, fg):
+        samples_per_symbol = 8
+        symbol_rate = 32000
+        bt = 0.3                # Gaussian filter bandwidth * symbol time
+
+        src_scale = gr.multiply_const_ff(32767)
+        f2s = gr.float_to_short()
+        voice_coder = gsm_full_rate.encode_sp()
+
+        channel_coder = gr.fake_channel_encoder_pp(GSM_FRAME_SIZE, AIR_FRAME_SIZE)
+        p2s = gr.parallel_to_serial(gr.sizeof_char, AIR_FRAME_SIZE)
+
+        mod = gmsk_mod(fg, sps=samples_per_symbol,
+                       symbol_rate=symbol_rate, bt=bt,
+                       p_size=AIR_FRAME_SIZE)
+
+        fg.connect(src_scale, f2s, voice_coder, channel_coder, p2s, mod)
+        gr.hier_block.__init__(self, fg, src_scale, mod)
+
+
+class digital_voice_rx(gr.hier_block):
+    """
+    Hierarchical block for digital voice reception.
+
+    The input is 256kS/sec GMSK modulated complex baseband signal.
+    The output is 8kS/sec floating point audio in the range [-1,+1]
+    """
+    def __init__(self, fg):
+        samples_per_symbol = 8
+        symbol_rate = 32000
+
+        demod = gmsk_demod(fg, sps=samples_per_symbol,
+                           symbol_rate=symbol_rate, 
+                           p_size=AIR_FRAME_SIZE)
+
+        s2p = gr.serial_to_parallel(gr.sizeof_char, AIR_FRAME_SIZE)
+        channel_decoder = gr.fake_channel_decoder_pp(AIR_FRAME_SIZE, GSM_FRAME_SIZE)
+
+        voice_decoder = gsm_full_rate.decode_ps()
+        s2f = gr.short_to_float ()
+        sink_scale = gr.multiply_const_ff(1.0/32767.)
+
+        fg.connect(demod, s2p, channel_decoder, voice_decoder, s2f, sink_scale)
+        gr.hier_block.__init__(self, fg, demod, sink_scale)