--- /dev/null
+/* -*- 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_lms.h>
+#include <assert.h>
+#include <algorithm>
+#include <atsci_pnXXX.h>
+
+#include <stdio.h>
+
+using std::min;
+using std::max;
+
+static const int NTAPS = 256;
+static const int NPRETAPS = (int) (NTAPS * 0.8); // probably should be either .2 or .8
+
+
+// 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);
+
+
+atsci_equalizer_lms::atsci_equalizer_lms () : d_taps (NTAPS)
+{
+ for (int i = 0; i < NTAPS; i++) {
+ d_taps[i] = 0.0;
+ }
+ trainingfile=fopen("taps.txt","w");
+}
+
+atsci_equalizer_lms::~atsci_equalizer_lms ()
+{
+}
+
+void
+atsci_equalizer_lms::reset ()
+{
+ atsci_equalizer::reset (); // invoke superclass
+
+ for (int i = 0; i < NTAPS; i++) {
+ d_taps[i] = 0.0;
+ }
+}
+
+int
+atsci_equalizer_lms::ntaps () const
+{
+ return NTAPS;
+}
+
+int
+atsci_equalizer_lms::npretaps () const
+{
+ return NPRETAPS;
+}
+
+/*!
+ * 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_lms::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_lms::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_lms::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 < NTAPS; i++)
+ fprintf(trainingfile,"%f ",d_taps[i]);
+
+ fprintf (trainingfile,"\n");
+ }
+
+}
+
+// ----------------------------------------------------------------
+
+//
+// filter a single output
+//
+float
+atsci_equalizer_lms::filter1 (const float input[])
+{
+ static const int N_UNROLL = 4;
+
+ float acc0 = 0;
+ float acc1 = 0;
+ float acc2 = 0;
+ float acc3 = 0;
+
+
+ unsigned i = 0;
+ unsigned n = (NTAPS / N_UNROLL) * N_UNROLL;
+
+ for (i = 0; i < n; i += N_UNROLL){
+ acc0 += d_taps[i + 0] * input[i + 0];
+ acc1 += d_taps[i + 1] * input[i + 1];
+ acc2 += d_taps[i + 2] * input[i + 2];
+ acc3 += d_taps[i + 3] * input[i + 3];
+ }
+
+ for (; i < (unsigned) NTAPS; i++)
+ acc0 += d_taps[i] * input[i];
+
+ return (acc0 + acc1 + acc2 + acc3);
+}
+
+//
+// filter and adapt a single output
+//
+float
+atsci_equalizer_lms::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 < NTAPS; i++){
+ d_taps[i] = d_taps[i] - BETA * e * (double)(input[i]);
+ }
+
+ return y;
+}
+
+void
+atsci_equalizer_lms::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_lms::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];
+}
projects / debian / gnuradio / blobdiff