--- /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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <cppunit/TestAssert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <atsci_single_viterbi.h>
+#include <qa_atsci_single_viterbi.h>
+#include <random.h>
+#include <string.h>
+
+
+static const int NTRIALS = 50;
+static const int MAXERRORS = 10;
+static const int NN = 200;
+
+static const int MAXDIBIT = 3;
+
+void
+qa_atsci_single_viterbi::encode_block (unsigned char *out, unsigned char *in,
+ unsigned int n)
+{
+ for (unsigned int i = 0; i < n; i++) {
+ out[i] = encoder.encode(in[i]);
+ }
+}
+
+
+void
+qa_atsci_single_viterbi::decode_block (unsigned char *out, unsigned char *in,
+ unsigned int n, float noise_factor)
+{
+ for (unsigned int i = 0; i < n; i++) {
+ out[i] = decoder.decode((2*in[i]-7) + noise () * noise_factor);
+ }
+}
+
+float
+qa_atsci_single_viterbi::noise ()
+{
+ return 2.0 * ((float) random () / RANDOM_MAX - 0.5); // uniformly (-1, 1)
+}
+
+void
+qa_atsci_single_viterbi::t0 ()
+{
+ int blocklen = NN;
+ unsigned char in[blocklen];
+ unsigned char enc[blocklen];
+ unsigned char out[blocklen];
+ int decoder_errors = 0;
+ int delay = decoder.delay ();
+ int i;
+
+ // printf (" Delay is %d.\n", delay);
+
+ srandom (27); // reproducable sequence of "random" values
+
+ for (int nt = 0; nt < NTRIALS; nt++){
+
+ // load block with random data and encode
+
+ for (i = 0; i < (blocklen-delay); i++)
+ in[i] = random () & MAXDIBIT;
+ for ( ; i < blocklen; i++)
+ in[i] = 0; /* To empty the delay buffers */
+
+ encoder.reset ();
+ encode_block (enc, in, blocklen);
+
+ decoder.reset ();
+
+ // decode the block
+ decode_block (out, enc, blocklen, 1.0);
+
+ // int offset = delay/4;
+ int offset = 2;
+ bool differs = (memcmp (in+offset,
+ out+delay+offset, blocklen-(delay+offset)));
+
+ // initial values after reset are 0
+ for (i = 0; i < delay; i++){
+ if (out[i] != 0)
+ printf (" initial output at %i is %X, not 0\n",
+ i, out[i]);
+ }
+
+ if (differs){
+ printf (" incorrect data\n");
+
+ printf ("\n Erroneous result dibits:");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ if (in[erri] != out[erri+delay])
+ printf (" %d", erri);
+ }
+ printf ("\n In: ");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %d", in[erri]);
+ }
+ printf ("\n Out: ");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %d", out[erri+delay]);
+ }
+ printf ("\n Errs:");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %c", (in[erri] != out[erri+delay])? '*': ' ');
+ }
+ printf ("\n THIS IS A REAL PROBLEM.\n");
+ decoder_errors++;
+ }
+ }
+
+ printf (" Summary: %d decoder errors out of %d trials.\n",
+ decoder_errors, NTRIALS);
+
+ CPPUNIT_ASSERT (decoder_errors == 0);
+}
+
+void
+qa_atsci_single_viterbi::t1 ()
+{
+ int blocklen = NN;
+ unsigned char in[blocklen];
+ unsigned char enc[blocklen];
+ unsigned char out[blocklen];
+ int errlocs[NN];
+ int errval;
+ int errloc;
+ int decoder_errors = 0;
+ int delay = decoder.delay ();
+ int i;
+
+ // printf (" Delay is %d.\n", delay);
+
+ srandom (1); // reproducable sequence of "random" values
+
+ for (int nt = 0; nt < NTRIALS; nt++){
+
+ // test up to the error correction capacity of the code
+ for (int errors = 0; errors <= MAXERRORS; errors++){
+
+ // load block with random data and encode
+
+ for (i = 0; i < (blocklen-delay); i++)
+ in[i] = random () & MAXDIBIT;
+ for ( ; i < blocklen; i++)
+ in[i] = 0; /* To empty the delay buffers */
+
+ encoder.reset ();
+ encode_block (enc, in, blocklen);
+
+ // Now generate 0 to N errors in the encoded symbols.
+ //
+ // If we restrict ourselves to damaging the low-order bit,
+ // our decoder finds and fixes the vast majority of errors.
+ //
+ // If we munge any or all of the three bits of the symbol,
+ // our decoder frequently gets the wrong data even with a single
+ // error.
+ //
+ // Let's see what it can do with just the two low-order bits.
+ //
+ // ALSO: Don't let any error be within 12 spots of another
+ // error. This simulates the muxed behavior.
+
+ memset (errlocs, 0, sizeof (errlocs));
+
+ for (int j = 0; j < errors; j++){
+
+ do {
+ // errval = random () & 3; // FIXME: 1; // FIXME: MAXSYM;
+ errval = random () & 1; // FIXME: 1; // FIXME: MAXSYM;
+ } while (errval == 0); // error value must be non-zero
+
+ // Don't insert errors in the first delay slot, since we
+ // don't have valid history to correct them. Also, don't
+ // insert burst errors (adjacent errors), or errors within 2,
+ // since we can't reliably correct them. Also we must not choose
+ // the same location twice when inserting an error.
+
+ do {
+ errloc = random () % NN;
+ } while (errloc < delay || errlocs[errloc] != 0
+ || (errloc > 0 && errlocs[errloc-1] != 0)
+ || (errloc > 1 && errlocs[errloc-2] != 0)
+ || (errloc < (NN-1) && errlocs[errloc+1] != 0)
+ || (errloc < (NN-2) && errlocs[errloc+2] != 0));
+
+ errlocs[errloc] = 1;
+
+ enc[errloc] ^= errval; // cause the error
+ }
+
+ // decode the errored block
+ decoder.reset ();
+ decode_block (out, enc, blocklen, 0.5);
+
+ // int offset = delay/4;
+ int offset = 2;
+ bool differs = (memcmp (in+offset,
+ out+delay+offset, blocklen-(delay+offset)));
+
+ // initial values after reset are 0
+ for (i = 0; i < delay; i++){
+ if (out[i] != 0)
+ printf (" initial output at %i is %X, not 0\n",
+ i, out[i]);
+ }
+
+ if (differs){
+ printf (" %2d errors introduced, %scorrect data\n",
+ errors, differs? "in": "");
+
+ // FIXME, should we be able to tell how many errs too?
+ if (differs) {
+ const int ERRTOL = 12; /* Or relate to delay? */
+ int shouldfix = 1;
+ int lasti = -ERRTOL;
+
+ printf ( " Inserted errors: ");
+ for (int erri = 0; erri < NN; erri++) {
+ if (errlocs[erri]) {
+ printf (" %d", erri);
+ // if (erri < lasti+ERRTOL)
+ // shouldfix = 0;
+ lasti = erri;
+ }
+ }
+ printf ("\n Erroneous result dibits:");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ if (in[erri] != out[erri+delay])
+ printf (" %d", erri);
+ }
+ printf ("\n In: ");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %d", in[erri]);
+ }
+ printf ("\n Out: ");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %d", out[erri+delay]);
+ }
+ printf ("\n Errs:");
+ for (int erri = 0; erri < (NN-delay); erri++) {
+ printf (" %c", (in[erri] != out[erri+delay])? '*': ' ');
+ }
+ if (shouldfix)
+ printf ("\n THIS IS A REAL PROBLEM.\n");
+ else
+ printf ("\n BUT THAT'S OK since errors are too close.\n");
+ if (shouldfix)
+ decoder_errors++;
+ }
+ }
+ }
+ }
+
+ printf (" Summary: %d decoder errors out of %d trials.\n",
+ decoder_errors, (MAXERRORS*NTRIALS));
+
+ CPPUNIT_ASSERT (decoder_errors <= (MAXERRORS*NTRIALS) * .1);
+}
projects / debian / gnuradio / blobdiff