From a7c7cf1186ec73786e6bbefb430c940c8747f857 Mon Sep 17 00:00:00 2001
From: Ben Reynwar <ben@reynwar.net>
Date: Thu, 7 Mar 2013 23:11:20 -0700
Subject: digital: Enabling uninstalled python imports.
---
gr-digital/python/digital/psk.py | 138 +++++++++++++++++++++++++++++++++++++++
1 file changed, 138 insertions(+)
create mode 100644 gr-digital/python/digital/psk.py
(limited to 'gr-digital/python/digital/psk.py')
diff --git a/gr-digital/python/digital/psk.py b/gr-digital/python/digital/psk.py
new file mode 100644
index 0000000000..1816ffb4ba
--- /dev/null
+++ b/gr-digital/python/digital/psk.py
@@ -0,0 +1,138 @@
+#
+# Copyright 2005,2006,2011 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.
+#
+
+"""
+PSK modulation and demodulation.
+"""
+
+from math import pi, log
+from cmath import exp
+
+import digital_swig
+import modulation_utils
+from utils import mod_codes, gray_code
+from generic_mod_demod import generic_mod, generic_demod
+from generic_mod_demod import shared_mod_args, shared_demod_args
+
+# Default number of points in constellation.
+_def_constellation_points = 4
+# The default encoding (e.g. gray-code, set-partition)
+_def_mod_code = mod_codes.GRAY_CODE
+# Default use of differential encoding
+_def_differential = True
+
+def create_encodings(mod_code, arity, differential):
+ post_diff_code = None
+ if mod_code not in mod_codes.codes:
+ raise ValueError('That modulation code does not exist.')
+ if mod_code == mod_codes.GRAY_CODE:
+ if differential:
+ pre_diff_code = gray_code.gray_code(arity)
+ post_diff_code = None
+ else:
+ pre_diff_code = []
+ post_diff_code = gray_code.gray_code(arity)
+ elif mod_code == mod_codes.NO_CODE:
+ pre_diff_code = []
+ post_diff_code = None
+ else:
+ raise ValueError('That modulation code is not implemented for this constellation.')
+ return (pre_diff_code, post_diff_code)
+
+# /////////////////////////////////////////////////////////////////////////////
+# PSK constellation
+# /////////////////////////////////////////////////////////////////////////////
+
+def psk_constellation(m=_def_constellation_points, mod_code=_def_mod_code,
+ differential=_def_differential):
+ """
+ Creates a PSK constellation object.
+ """
+ k = log(m) / log(2.0)
+ if (k != int(k)):
+ raise StandardError('Number of constellation points must be a power of two.')
+ points = [exp(2*pi*(0+1j)*i/m) for i in range(0,m)]
+ pre_diff_code, post_diff_code = create_encodings(mod_code, m, differential)
+ if post_diff_code is not None:
+ inverse_post_diff_code = mod_codes.invert_code(post_diff_code)
+ points = [points[x] for x in inverse_post_diff_code]
+ constellation = digital_swig.constellation_psk(points, pre_diff_code, m)
+ return constellation
+
+# /////////////////////////////////////////////////////////////////////////////
+# PSK modulator
+# /////////////////////////////////////////////////////////////////////////////
+
+class psk_mod(generic_mod):
+ """
+ Hierarchical block for RRC-filtered PSK modulation.
+
+ The input is a byte stream (unsigned char) and the
+ output is the complex modulated signal at baseband.
+
+ Args:
+ constellation_points: Number of constellation points (must be a power of two) (integer).
+ mod_code: Whether to use a gray_code (digital.mod_codes.GRAY_CODE) or not (digital.mod_codes.NO_CODE).
+ differential: Whether to use differential encoding (boolean).
+ """
+ # See generic_mod for additional arguments
+ __doc__ += shared_mod_args
+
+ def __init__(self, constellation_points=_def_constellation_points,
+ mod_code=_def_mod_code,
+ differential=_def_differential,
+ *args, **kwargs):
+ constellation = psk_constellation(constellation_points, mod_code, differential)
+ super(psk_mod, self).__init__(constellation, differential, *args, **kwargs)
+
+# /////////////////////////////////////////////////////////////////////////////
+# PSK demodulator
+#
+# /////////////////////////////////////////////////////////////////////////////
+
+class psk_demod(generic_demod):
+
+ """
+ Hierarchical block for RRC-filtered PSK modulation.
+
+ The input is a byte stream (unsigned char) and the
+ output is the complex modulated signal at baseband.
+
+ Args:
+ constellation_points: Number of constellation points (must be a power of two) (integer).
+ mod_code: Whether to use a gray_code (digital.mod_codes.GRAY_CODE) or not (digital.mod_codes.NO_CODE).
+ differential: Whether to use differential encoding (boolean).
+ """
+ # See generic_mod for additional arguments
+ __doc__ += shared_mod_args
+ def __init__(self, constellation_points=_def_constellation_points,
+ mod_code=_def_mod_code,
+ differential=_def_differential,
+ *args, **kwargs):
+ constellation = psk_constellation(constellation_points, mod_code, differential)
+ super(psk_demod, self).__init__(constellation, differential, *args, **kwargs)
+
+#
+# Add these to the mod/demod registry
+#
+modulation_utils.add_type_1_mod('psk', psk_mod)
+modulation_utils.add_type_1_demod('psk', psk_demod)
+modulation_utils.add_type_1_constellation('psk', psk_constellation)
--
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