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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
import math
# These constellations are generated for Gray coding when symbos [1, ..., m] are used
# Mapping to Gray coding is therefore unnecessary
def make_constellation(m):
# number of bits/symbol (log2(M))
k = int(math.log10(m) / math.log10(2.0))
coeff = 1
const_map = []
for i in range(m):
a = (i&(0x01 << k-1)) >> k-1
b = (i&(0x01 << k-2)) >> k-2
bits_i = [((i&(0x01 << k-j-1)) >> k-j-1) for j in range(2, k, 2)]
bits_q = [((i&(0x01 << k-j-1)) >> k-j-1) for j in range(3, k, 2)]
ss = 0
ll = len(bits_i)
for ii in range(ll):
rr = 0
for jj in range(ll-ii):
rr = abs(bits_i[jj] - rr)
ss += rr*pow(2.0, ii+1)
re = (2*a-1)*(ss+1)
ss = 0
ll = len(bits_q)
for ii in range(ll):
rr = 0
for jj in range(ll-ii):
rr = abs(bits_q[jj] - rr)
ss += rr*pow(2.0, ii+1)
im = (2*b-1)*(ss+1)
a = max(re, im)
if a > coeff:
coeff = a
const_map.append(complex(re, im))
norm_map = [complex(i.real/coeff, i.imag/coeff) for i in const_map]
return norm_map
# Common definition of constellations for Tx and Rx
constellation = {
4 : make_constellation(4), # QAM4 (QPSK)
8 : make_constellation(8), # QAM8
16: make_constellation(16), # QAM16
64: make_constellation(64), # QAM64
256: make_constellation(256) # QAM256
}
# -----------------------
# Do Gray code
# -----------------------
# binary to gray coding
binary_to_gray = {
4 : range(4),
8 : range(8),
16: range(16),
64: range(64),
256: range(256)
}
# gray to binary
gray_to_binary = {
4 : range(4),
8 : range(8),
16: range(16),
64: range(64),
256: range(256)
}
# -----------------------
# Don't Gray code
# -----------------------
# identity mapping
binary_to_ungray = {
4 : range(4),
8 : range(8),
16: range(16),
64: range(64)
}
# identity mapping
ungray_to_binary = {
4 : range(4),
8 : range(8),
16: range(16),
64: range(64)
}
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