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-rw-r--r--gr-atsc/src/lib/atsci_equalizer_lms2.cc375
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diff --git a/gr-atsc/src/lib/atsci_equalizer_lms2.cc b/gr-atsc/src/lib/atsci_equalizer_lms2.cc
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--- a/gr-atsc/src/lib/atsci_equalizer_lms2.cc
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-/* -*- c++ -*- */
-/*
- * Copyright 2002 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.
- */
-
-#include <atsci_equalizer_lms2.h>
-#include <assert.h>
-#include <algorithm>
-#include <atsci_pnXXX.h>
-#include <cmath>
-#include <stdlib.h>
-#include <gr_math.h>
-#include <stdio.h>
-#include <boost/math/special_functions/fpclassify.hpp>
-
-using std::min;
-using std::max;
-
-static const int NFFTAPS = 64;
-static const int NFBTAPS = 192;
-
-// the length of the field sync pattern that we know unequivocally
-static const int KNOWN_FIELD_SYNC_LENGTH = 4 + 511 + 3 * 63;
-
-// static const float *get_data_seg_sync_training_sequence (int offset);
-static int get_field_sync_training_sequence_length (int offset);
-static const float *get_field_sync_training_sequence (int which_field, int offset);
-
-static inline int
-wrap (int d)
-{
- assert (d >= 0 && d <= (2 * NFBTAPS));
-
- if(d >= NFBTAPS)
- return d - NFBTAPS;
- return d;
-}
-
-static inline float
-slice (float d)
-{
- if (boost::math::isnan (d))
- return 0.0;
-
- if (d >= 0.0){
- if (d >= 4.0){
- if (d >= 6.0)
- return 7.0;
- else
- return 5.0;
- }
- if (d >= 2.0)
- return 3.0;
- return 1.0;
- }
- else
- return -slice (-d);
-}
-
-atsci_equalizer_lms2::atsci_equalizer_lms2 ()
- : d_taps_ff (NFFTAPS), d_taps_fb (NFBTAPS), d_old_output (NFBTAPS)
-{
- for (int i = 0; i < NFFTAPS; i++) {
- d_taps_ff[i] = 0.0;
- }
- for (int i = 0; i < NFBTAPS; i++) {
- d_taps_fb[i] = 0.0;
- d_old_output[i] = 0.0;
- }
- d_output_ptr = 0;
- trainingfile=fopen("taps.txt","w");
-}
-
-atsci_equalizer_lms2::~atsci_equalizer_lms2 ()
-{
-}
-
-void
-atsci_equalizer_lms2::reset ()
-{
- atsci_equalizer::reset (); // invoke superclass
- for (int i = 0; i < NFFTAPS; i++) {
- d_taps_ff[i] = 0.0;
- }
- for (int i = 0; i < NFBTAPS; i++) {
- d_taps_fb[i] = 0.0;
- d_old_output[i] = 0.0;
- }
- d_output_ptr = 0;
-}
-
-
-int
-atsci_equalizer_lms2::ntaps () const
-{
- return NFFTAPS + NFBTAPS;
-}
-
-int
-atsci_equalizer_lms2::npretaps () const
-{
- return NFFTAPS;
-}
-
-/*!
- * Input range is known NOT TO CONTAIN data segment syncs
- * or field syncs. This should be the fast path. In the
- * non decicion directed case, this just runs the input
- * through the filter without adapting it.
- *
- * \p input_samples has (nsamples + ntaps() - 1) valid entries.
- * input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be
- * referenced to compute the output values.
- */
-void
-atsci_equalizer_lms2::filter_normal (const float *input_samples,
- float *output_samples,
- int nsamples)
-{
- // handle data
- filterN (input_samples, output_samples, nsamples);
-}
-
-
-/*!
- * Input range is known to consist of only a data segment sync or a
- * portion of a data segment sync. \p nsamples will be in [1,4].
- * \p offset will be in [0,3]. \p offset is the offset of the input
- * from the beginning of the data segment sync pattern.
- *
- * \p input_samples has (nsamples + ntaps() - 1) valid entries.
- * input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be
- * referenced to compute the output values.
- */
-void
-atsci_equalizer_lms2::filter_data_seg_sync (const float *input_samples,
- float *output_samples,
- int nsamples,
- int offset)
-{
- // handle data
- // adaptN (input_samples, get_data_seg_sync_training_sequence (offset),
- // output_samples, nsamples);
- filterN (input_samples, output_samples, nsamples);
-
- // cerr << "Seg Sync: offset " << offset << "\tnsamples\t" << nsamples << "\t pre, 5 -5 -5 5\t" <<
- // output_samples[0] << "\t" << output_samples[1] << "\t" << output_samples[2] << "\t" << output_samples[3] << endl;
-
-}
-
-
-/*!
- * Input range is known to consist of only a field sync segment or a
- * portion of a field sync segment. \p nsamples will be in [1,832].
- * \p offset will be in [0,831]. \p offset is the offset of the input
- * from the beginning of the data segment sync pattern. We consider the
- * 4 symbols of the immediately preceding data segment sync to be the
- * first symbols of the field sync segment. \p which_field is in [0,1]
- * and specifies which field (duh).
- *
- * \p input_samples has (nsamples + ntaps() - 1) valid entries.
- * input_samples[0] .. input_samples[nsamples - 1 + ntaps() - 1] may be
- * referenced to compute the output values.
- */
-void
-atsci_equalizer_lms2::filter_field_sync (const float *input_samples,
- float *output_samples,
- int nsamples,
- int offset,
- int which_field)
-{
- // Only the first 4 + 511 + 3 * 63 symbols are completely defined.
- // Those after that the symbols are bilevel, so we could use decision feedback and use
- // that to train, but for now, don't train on them.
-
- int n = min (nsamples, get_field_sync_training_sequence_length (offset));
-
- // handle known training sequence
- adaptN (input_samples, get_field_sync_training_sequence (which_field, offset),
- output_samples, n);
-
- // just filter any unknown portion
- if (nsamples > n)
- filterN (&input_samples[n], &output_samples[n], nsamples - n);
-
- if (offset == 0 && nsamples > 0){
- for (int i = 0; i < NFFTAPS; i++)
- fprintf(trainingfile,"%f ",d_taps_ff[i]);
- for (int i = 0; i < NFBTAPS; i++)
- fprintf(trainingfile,"%f ",d_taps_fb[i]);
- fprintf (trainingfile,"\n");
- }
-
-}
-
-// ----------------------------------------------------------------
-
-//
-// filter a single output
-//
-float
-atsci_equalizer_lms2::filter1 (const float input[])
-{
- static const int N_UNROLL = 4;
-
- float acc0 = 0;
- float acc1 = 0;
- float acc2 = 0;
- float acc3 = 0;
- float acc = 0;
-
-
- unsigned i = 0;
- unsigned n = (NFFTAPS / N_UNROLL) * N_UNROLL;
-
- for (i = 0; i < n; i += N_UNROLL){
- acc0 += d_taps_ff[i + 0] * input[i + 0];
- acc1 += d_taps_ff[i + 1] * input[i + 1];
- acc2 += d_taps_ff[i + 2] * input[i + 2];
- acc3 += d_taps_ff[i + 3] * input[i + 3];
- }
-
- for (; i < (unsigned) NFFTAPS; i++)
- acc0 += d_taps_ff[i] * input[i];
-
- acc = (acc0 + acc1 + acc2 + acc3);
-
- d_output_ptr = wrap (d_output_ptr + 1);
-
- for (int i = 0; i < NFBTAPS; i++) {
- acc -= d_taps_fb[i] * d_old_output[wrap(i + d_output_ptr)];
- }
-
- if (boost::math::isnan (acc)){
- abort ();
- }
-
- d_old_output[d_output_ptr] = slice (acc);
- return acc;
-}
-
-//
-// filter and adapt a single output
-//
-float kludge ()
-{
- return 0.0;
-}
-
-float
-atsci_equalizer_lms2::adapt1 (const float input[], float ideal_output)
-{
- static const double BETA = 0.00005; // FIXME figure out what this ought to be
- // FIXME add gear-shifting
-
- double y = filter1 (input);
- double e = y - ideal_output;
-
- // update taps...
- for (int i = 0; i < NFFTAPS; i++){
- d_taps_ff[i] = d_taps_ff[i] - BETA * e * (double)(input[i]);
- }
-
- for (int i = 0; i < NFBTAPS; i++){
- // d_taps_fb[i] = d_taps_fb[i] - BETA * e * (double)d_old_output[wrap(i+d_output_ptr)];
- d_taps_fb[i] = d_taps_fb[i] - kludge() * e * (double)d_old_output[wrap(i+d_output_ptr)];
- }
-
- return y;
-}
-
-void
-atsci_equalizer_lms2::filterN (const float *input_samples,
- float *output_samples,
- int nsamples)
-{
- for (int i = 0; i < nsamples; i++)
- output_samples[i] = filter1 (&input_samples[i]);
-}
-
-
-void
-atsci_equalizer_lms2::adaptN (const float *input_samples,
- const float *training_pattern,
- float *output_samples,
- int nsamples)
-{
- for (int i = 0; i < nsamples; i++)
- output_samples[i] = adapt1 (&input_samples[i], training_pattern[i]);
-}
-
-// ----------------------------------------------------------------
-
-static float
-bin_map (int bit)
-{
- return bit ? +5 : -5;
-}
-
-static void
-init_field_sync_common (float *p, int mask)
-
-{
- int i = 0;
-
- p[i++] = bin_map (1); // data segment sync pulse
- p[i++] = bin_map (0);
- p[i++] = bin_map (0);
- p[i++] = bin_map (1);
-
- for (int j = 0; j < 511; j++) // PN511
- p[i++] = bin_map (atsc_pn511[j]);
-
- for (int j = 0; j < 63; j++) // PN63
- p[i++] = bin_map (atsc_pn63[j]);
-
- for (int j = 0; j < 63; j++) // PN63, toggled on field 2
- p[i++] = bin_map (atsc_pn63[j] ^ mask);
-
- for (int j = 0; j < 63; j++) // PN63
- p[i++] = bin_map (atsc_pn63[j]);
-
- assert (i == KNOWN_FIELD_SYNC_LENGTH);
-}
-
-#if 0
-static const float *
-get_data_seg_sync_training_sequence (int offset)
-{
- static const float training_data[4] = { +5, -5, -5, +5 };
- return &training_data[offset];
-}
-#endif
-
-static int
-get_field_sync_training_sequence_length (int offset)
-{
- return max (0, KNOWN_FIELD_SYNC_LENGTH - offset);
-}
-
-static const float *
-get_field_sync_training_sequence (int which_field, int offset)
-{
- static float *field_1 = 0;
- static float *field_2 = 0;
-
- if (field_1 == 0){
- field_1 = new float[KNOWN_FIELD_SYNC_LENGTH];
- field_2 = new float[KNOWN_FIELD_SYNC_LENGTH];
- init_field_sync_common (field_1, 0);
- init_field_sync_common (field_2, 1);
- }
-
- if (which_field == 0)
- return &field_1[offset];
- else
- return &field_2[offset];
-}
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