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authorTom Rondeau2011-07-17 17:25:57 -0400
committerTom Rondeau2011-07-17 17:25:57 -0400
commitf7b9a0c6922c86cd54c1300ab45209d8e2db13df (patch)
tree5ede528cd302e85bc40edcad876525659f4e1ed2 /gr-digital/python/psk.py
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parent04409d2ba42ac5b372a7b6bb7e9c8de5722d76d7 (diff)
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Merge branch '8psk' into next
Conflicts: gr-msdd6000/src/Makefile.swig.gen
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+#
+# Copyright 2005,2006 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 math import pi, sqrt, log10
+import math, cmath
+
+# The following algorithm generates Gray coded constellations for M-PSK for M=[2,4,8]
+def make_gray_constellation(m):
+ # number of bits/symbol (log2(M))
+ k = int(log10(m) / log10(2.0))
+
+ coeff = 1
+ const_map = []
+ bits = [0]*3
+ for i in range(m):
+ # get a vector of the k bits to use in this mapping
+ bits[3-k:3] = [((i&(0x01 << k-j-1)) >> k-j-1) for j in range(k)]
+
+ theta = -(2*bits[0]-1)*(2*pi/m)*(bits[0]+abs(bits[1]-bits[2])+2*bits[1])
+ re = math.cos(theta)
+ im = math.sin(theta)
+ const_map.append(complex(re, im)) # plug it into the constellation
+
+ # return the constellation; by default, it is normalized
+ return const_map
+
+# This makes a constellation that increments around the unit circle
+def make_constellation(m):
+ return [cmath.exp(i * 2 * pi / m * 1j) for i in range(m)]
+
+# Common definition of constellations for Tx and Rx
+constellation = {
+ 2 : make_constellation(2), # BPSK
+ 4 : make_constellation(4), # QPSK
+ 8 : make_constellation(8) # 8PSK
+ }
+
+gray_constellation = {
+ 2 : make_gray_constellation(2), # BPSK
+ 4 : make_gray_constellation(4), # QPSK
+ 8 : make_gray_constellation(8) # 8PSK
+ }
+
+# -----------------------
+# Do Gray code
+# -----------------------
+# binary to gray coding -- constellation does Gray coding
+binary_to_gray = {
+ 2 : range(2),
+ 4 : [0,1,3,2],
+ 8 : [0, 1, 3, 2, 7, 6, 4, 5]
+ }
+
+# gray to binary
+gray_to_binary = {
+ 2 : range(2),
+ 4 : [0,1,3,2],
+ 8 : [0, 1, 3, 2, 6, 7, 5, 4]
+ }
+
+# -----------------------
+# Don't Gray code
+# -----------------------
+# identity mapping
+binary_to_ungray = {
+ 2 : range(2),
+ 4 : range(4),
+ 8 : range(8)
+ }
+
+# identity mapping
+ungray_to_binary = {
+ 2 : range(2),
+ 4 : range(4),
+ 8 : range(8)
+ }