diff options
| author | Ben Reynwar <ben@reynwar.net> | 2012-09-30 17:23:19 -0700 |
|---|---|---|
| committer | Ben Reynwar <ben@reynwar.net> | 2012-09-30 17:23:19 -0700 |
| commit | 33d9cf8800d3b4c0bbbff09b7588c21ed35e3220 (patch) | |
| tree | 8c34108db2e071d1ab9dd7143b97b3c2da725221 | |
| parent | 96f181f29afbae43fa449297a232637fadf426d0 (diff) | |
digital: Fixed scaling bug in QAM constellations.
| -rw-r--r-- | gr-digital/include/digital_constellation.h | 3 | ||||
| -rw-r--r-- | gr-digital/lib/digital_constellation.cc | 13 | ||||
| -rwxr-xr-x | gr-digital/python/qa_constellation.py | 4 | ||||
| -rwxr-xr-x | gr-digital/python/qa_constellation_receiver.py | 2 |
4 files changed, 21 insertions, 1 deletions
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 |