def qam_constellation(constellation_points=_def_constellation_points,
differential=_def_differential,
mod_code=_def_mod_code):
"""
Creates a QAM constellation object.
"""
if mod_code == mod_codes.GRAY_CODE:
gray_coded = True
elif mod_code == mod_codes.NO_CODE:
gray_coded = False
else:
raise ValueError("Mod code is not implemented for QAM")
if differential:
points = make_differential_constellation(constellation_points,
gray_coded)
else:
points = make_non_differential_constellation(constellation_points,
gray_coded)
side = int(sqrt(constellation_points))
width = 2.0 / (side - 1)
# No pre-diff code
# Should add one so that we can gray-code the quadrant bits too.
pre_diff_code = []
constellation = digital_swig.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
return constellation
def dvbt_16qam_constellation(m, differential=_def_differential, mod_code=_def_mod_code):
"""
Creates a QAM constellation object.
"""
if m != 16:
raise ValueError("16QAM can only have 16 constellation points.")
if mod_code != mod_codes.GRAY_CODE:
raise ValueError("Gray encoding missing.")
side = int(sqrt(m))
#width = 2.0
width = 2.0/(side-1)
points = [complex(3,3),complex(-3,3),complex(3,-3), complex(-3,-3),
complex(1,3),complex(-1,3),complex(1,-3),complex(-1,-3),
complex(3,1),complex(-3,1),complex(3,-1), complex(-3,-1),
complex(1,1),complex(-1,1),complex(1,-1),complex(-1,-1)]
norm_points = map(lambda pt: pt / (math.sqrt(10)), points)
# No pre-diff code
# Should add one so that we can gray-code the quadrant bits too.
pre_diff_code = []
constellation = digital_swig.constellation_rect(norm_points, pre_diff_code, 4,
side, side, width, width)
return constellation
def qam_constellation(constellation_points=_def_constellation_points,
differential=_def_differential,
mod_code=_def_mod_code):
"""
Creates a QAM constellation object.
"""
if mod_code == mod_codes.GRAY_CODE:
gray_coded = True
elif mod_code == mod_codes.NO_CODE:
gray_coded = False
else:
raise ValueError("Mod code is not implemented for QAM")
if differential:
points = make_differential_constellation(constellation_points, gray_coded=False)
else:
points = make_non_differential_constellation(constellation_points, gray_coded)
side = int(sqrt(constellation_points))
width = 2.0/(side-1)
# For differential and gray-coded then gray-code the first two
# bits with a pre_diff_code.
# FIXME: It would be good to have a test to make sure that gray-coded constellations
# are really gray-coded. Perhaps by checking on the correlation between bit-errors.
if differential and gray_coded:
m = constellation_points
pre_diff_code = range(0, m/2) + range(3*m/4, m) + range(m/2, 3*m/4)
else:
pre_diff_code = []
constellation = digital.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
return constellation
def qam_constellation(constellation_points=_def_constellation_points,
differential=_def_differential,
mod_code=_def_mod_code):
"""
Creates a QAM constellation object.
"""
if mod_code == mod_codes.GRAY_CODE:
gray_coded = True
elif mod_code == mod_codes.NO_CODE:
gray_coded = False
else:
raise ValueError("Mod code is not implemented for QAM")
if differential:
points = make_differential_constellation(constellation_points, gray_coded)
else:
points = make_non_differential_constellation(constellation_points, gray_coded)
side = int(sqrt(constellation_points))
width = 2.0/(side-1)
# No pre-diff code
# Should add one so that we can gray-code the quadrant bits too.
pre_diff_code = []
print points
constellation = digital_swig.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
return constellation
def qam32_holeinside_constellation(large_ampls_to_corners=False):
# First make constellation for one quadrant.
# 0 1 2
# 2 - 010 111 110
# 1 - 011 101 100
# 0 - 000 001
# Have put hole in the side rather than corner.
# Corner point is helpful for frequency locking.
# It has an attempt at some gray-coding, but not
# a very good one.
# Indices are (horizontal, vertical).
indices_and_numbers = (
((0, 0), 0b000),
((0, 1), 0b011),
((0, 2), 0b010),
((1, 0), 0b001),
((1, 1), 0b101),
((1, 2), 0b111),
((2, 1), 0b100),
((2, 2), 0b110),
)
points = [None] * 32
for indices, number in indices_and_numbers:
p_in_quadrant = 0.5 + indices[0] + 1j * (0.5 + indices[1])
for quadrant in range(4):
index = number + 8 * quadrant
rotation = pow(1j, quadrant)
p = p_in_quadrant * rotation
points[index] = p
side = 6
width = 1
# Double number of boxes on side
# This is so that points in the 'hole' get assigned correctly.
side = 12
width = 0.5
pre_diff_code = []
if not large_ampls_to_corners:
constellation = digital_swig.constellation_rect(
points, pre_diff_code, 4, side, side, width, width)
else:
sector_values = large_ampls_to_corners_mapping(side, points, width)
constellation = digital_swig.constellation_expl_rect(
points, pre_diff_code, 4, side, side, width, width, sector_values)
return constellation
def qam32_holeinside_constellation(large_ampls_to_corners=False):
# First make constellation for one quadrant.
# 0 1 2
# 2 - 010 111 110
# 1 - 011 101 100
# 0 - 000 001
# Have put hole in the side rather than corner.
# Corner point is helpful for frequency locking.
# It has an attempt at some gray-coding, but not
# a very good one.
# Indices are (horizontal, vertical).
indices_and_numbers = (
((0, 0), 0b000),
((0, 1), 0b011),
((0, 2), 0b010),
((1, 0), 0b001),
((1, 1), 0b101),
((1, 2), 0b111),
((2, 1), 0b100),
((2, 2), 0b110),
)
points = [None]*32
for indices, number in indices_and_numbers:
p_in_quadrant = 0.5+indices[0] + 1j*(0.5+indices[1])
for quadrant in range(4):
index = number + 8 * quadrant
rotation = pow(1j, quadrant)
p = p_in_quadrant * rotation
points[index] = p
side = 6
width = 1
# Double number of boxes on side
# This is so that points in the 'hole' get assigned correctly.
side = 12
width = 0.5
pre_diff_code = []
if not large_ampls_to_corners:
constellation = digital_swig.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
else:
sector_values = large_ampls_to_corners_mapping(side, points, width)
constellation = digital_swig.constellation_expl_rect(
points, pre_diff_code, 4, side, side, width, width, sector_values)
return constellation
def qam_constellation(constellation_points=_def_constellation_points,
differential=_def_differential,
mod_code=_def_mod_code,
large_ampls_to_corners=False):
"""
Creates a QAM constellation object.
If large_ampls_to_corners=True then sectors that are probably
occupied due to a phase offset, are not mapped to the closest
constellation point. Rather we take into account the fact that a
phase offset is probably the problem and map them to the closest
corner point. It's a bit hackish but it seems to improve
frequency locking.
"""
if mod_code == mod_codes.GRAY_CODE:
gray_coded = True
elif mod_code == mod_codes.NO_CODE:
gray_coded = False
else:
raise ValueError("Mod code is not implemented for QAM")
if differential:
points = make_differential_constellation(constellation_points, gray_coded=False)
else:
points = make_non_differential_constellation(constellation_points, gray_coded)
side = int(sqrt(constellation_points))
width = 2.0/(side-1)
# No pre-diff code
# Should add one so that we can gray-code the quadrant bits too.
pre_diff_code = []
if not large_ampls_to_corners:
constellation = digital.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
else:
sector_values = large_ampls_to_corners_mapping(side, points, width)
constellation = digital.constellation_expl_rect(
points, pre_diff_code, 4, side, side, width, width, sector_values)
return constellation
def qam_constellation(constellation_points=_def_constellation_points,
differential=_def_differential,
mod_code=_def_mod_code,
large_ampls_to_corners=False):
"""
Creates a QAM constellation object.
If large_ampls_to_corners=True then sectors that are probably
occupied due to a phase offset, are not mapped to the closest
constellation point. Rather we take into account the fact that a
phase offset is probably the problem and map them to the closest
corner point. It's a bit hackish but it seems to improve
frequency locking.
"""
if mod_code == mod_codes.GRAY_CODE:
gray_coded = True
elif mod_code == mod_codes.NO_CODE:
gray_coded = False
else:
raise ValueError("Mod code is not implemented for QAM")
if differential:
points = make_differential_constellation(constellation_points, gray_coded=False)
else:
points = make_non_differential_constellation(constellation_points, gray_coded)
side = int(sqrt(constellation_points))
width = 2.0/(side-1)
# No pre-diff code
# Should add one so that we can gray-code the quadrant bits too.
pre_diff_code = []
if not large_ampls_to_corners:
constellation = digital.constellation_rect(points, pre_diff_code, 4,
side, side, width, width)
else:
sector_values = large_ampls_to_corners_mapping(side, points, width)
constellation = digital.constellation_expl_rect(
points, pre_diff_code, 4, side, side, width, width, sector_values)
return constellation
