From 33d9cf8800d3b4c0bbbff09b7588c21ed35e3220 Mon Sep 17 00:00:00 2001
From: Ben Reynwar <ben@reynwar.net>
Date: Sun, 30 Sep 2012 17:23:19 -0700
Subject: digital: Fixed scaling bug in QAM constellations.
---
gr-digital/include/digital_constellation.h | 3 +++
gr-digital/lib/digital_constellation.cc | 13 +++++++++++++
gr-digital/python/qa_constellation.py | 4 ++++
gr-digital/python/qa_constellation_receiver.py | 2 +-
4 files changed, 21 insertions(+), 1 deletion(-)
(limited to 'gr-digital')
diff --git a/gr-digital/include/digital_constellation.h b/gr-digital/include/digital_constellation.h
index a72bfb74c5..76cd30b25f 100644
--- a/gr-digital/include/digital_constellation.h
+++ b/gr-digital/include/digital_constellation.h
@@ -120,6 +120,9 @@ public:
unsigned int d_rotational_symmetry;
unsigned int d_dimensionality;
unsigned int d_arity;
+ // The orignal constellation points were multiplied by this factor to get a
+ // constellation with average magnitude 1.
+ float d_scalefactor;
float get_distance(unsigned int index, const gr_complex *sample);
unsigned int get_closest_point(const gr_complex *sample);
diff --git a/gr-digital/lib/digital_constellation.cc b/gr-digital/lib/digital_constellation.cc
index d9a53c4930..da79f2caa4 100644
--- a/gr-digital/lib/digital_constellation.cc
+++ b/gr-digital/lib/digital_constellation.cc
@@ -49,6 +49,17 @@ digital_constellation::digital_constellation (std::vector<gr_complex> constellat
d_rotational_symmetry(rotational_symmetry),
d_dimensionality(dimensionality)
{
+ // Scale constellation points so that average magnitude is 1.
+ float summed_mag = 0;
+ unsigned int constsize = d_constellation.size();
+ for (unsigned int i=0; i<constsize; i++) {
+ gr_complex c = d_constellation[i];
+ summed_mag += sqrt(c.real()*c.real() + c.imag()*c.imag());
+ }
+ d_scalefactor = constsize/summed_mag;
+ for (unsigned int i=0; i<constsize; i++) {
+ d_constellation[i] = d_constellation[i]*d_scalefactor;
+ }
if (pre_diff_code.size() == 0)
d_apply_pre_diff_code = false;
else if (pre_diff_code.size() != constellation.size())
@@ -293,6 +304,8 @@ digital_constellation_rect::digital_constellation_rect (std::vector<gr_complex>
n_real_sectors(real_sectors), n_imag_sectors(imag_sectors),
d_width_real_sectors(width_real_sectors), d_width_imag_sectors(width_imag_sectors)
{
+ d_width_real_sectors *= d_scalefactor;
+ d_width_imag_sectors *= d_scalefactor;
find_sector_values();
}
diff --git a/gr-digital/python/qa_constellation.py b/gr-digital/python/qa_constellation.py
index b17d2a0fcb..6962ec6338 100755
--- a/gr-digital/python/qa_constellation.py
+++ b/gr-digital/python/qa_constellation.py
@@ -69,6 +69,10 @@ tested_constellation_info = (
{'m': (2, 4, 8, 16, 32, 64),
'mod_code': tested_mod_codes, },
True, None),
+ (qam.qam_constellation,
+ {'constellation_points': (4, 16, 64),
+ 'mod_code': tested_mod_codes, },
+ True, None),
(digital_swig.constellation_bpsk, {}, True, None),
(digital_swig.constellation_qpsk, {}, False, None),
(digital_swig.constellation_dqpsk, {}, True, None),
diff --git a/gr-digital/python/qa_constellation_receiver.py b/gr-digital/python/qa_constellation_receiver.py
index 2d25433b92..fe9c923c54 100755
--- a/gr-digital/python/qa_constellation_receiver.py
+++ b/gr-digital/python/qa_constellation_receiver.py
@@ -39,7 +39,7 @@ SEED = 1239
# We need this many to let the frequency recovery block converge.
DATA_LENGTH = 2000
# Test fails if fraction of output that is correct is less than this.
-REQ_CORRECT = 0.7
+REQ_CORRECT = 0.9
# CHANNEL PARAMETERS
NOISE_VOLTAGE = 0.01
--
cgit v1.2.3
From a5f794128d8386ff0067cbe2928af4ded728d3b2 Mon Sep 17 00:00:00 2001
From: Ben Reynwar <ben@reynwar.net>
Date: Mon, 1 Oct 2012 21:45:43 -0700
Subject: digital: Increase acceptable BER in qa_constellation_receiver back to
prior value.
---
gr-digital/python/qa_constellation_receiver.py | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'gr-digital')
diff --git a/gr-digital/python/qa_constellation_receiver.py b/gr-digital/python/qa_constellation_receiver.py
index fe9c923c54..2d25433b92 100755
--- a/gr-digital/python/qa_constellation_receiver.py
+++ b/gr-digital/python/qa_constellation_receiver.py
@@ -39,7 +39,7 @@ SEED = 1239
# We need this many to let the frequency recovery block converge.
DATA_LENGTH = 2000
# Test fails if fraction of output that is correct is less than this.
-REQ_CORRECT = 0.9
+REQ_CORRECT = 0.7
# CHANNEL PARAMETERS
NOISE_VOLTAGE = 0.01
--
cgit v1.2.3