gr_adaptive_fir_ccf.cc

这是用python语言写的一个数字广播的信号处理工具包。利用它

/* -*- c++ -*- */
/*
 * Copyright 2004,2006 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 <gr_adaptive_fir_ccf.h>
#include <gr_io_signature.h>

gr_adaptive_fir_ccf::gr_adaptive_fir_ccf(char *name, int decimation, const std::vector<float> &taps)
  : gr_sync_decimator (name,
		       gr_make_io_signature (1, 1, sizeof(gr_complex)),
		       gr_make_io_signature (1, 1, sizeof(gr_complex)),
		       decimation),
    d_updated(false)
{
  d_taps = taps;
  set_history(d_taps.size());
}

void gr_adaptive_fir_ccf::set_taps(const std::vector<float> &taps)
{
  d_new_taps = taps;
  d_updated = true;
}

int gr_adaptive_fir_ccf::work(int noutput_items,
                              gr_vector_const_void_star &input_items,
                              gr_vector_void_star &output_items)
{
  gr_complex *in = (gr_complex *)input_items[0];
  gr_complex *out = (gr_complex *)output_items[0];

  if (d_updated) {
    d_taps = d_new_taps;
    set_history(d_taps.size());
    d_updated = false;
    return 0;		     // history requirements may have changed.
  }

  int j = 0, k, l = d_taps.size();
  for (int i = 0; i < noutput_items; i++) {
    // Generic dot product of d_taps[] and in[]
    gr_complex sum(0.0, 0.0);
    for (k = 0; k < l; k++)
      sum += d_taps[l-k-1]*in[j+k];
    out[i] = sum;
        
    // Adjust taps
    d_error = error(sum);
    for (k = 0; k < l; k++) {
      //printf("%f ", d_taps[k]);
      update_tap(d_taps[l-k-1], in[j+k]);
    }
    //printf("\n");
    
    j += decimation();
  }

  return noutput_items;
}