gr_sync_decimator.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 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_sync_decimator.h>

gr_sync_decimator::gr_sync_decimator (const std::string &name,
				      gr_io_signature_sptr input_signature,
				      gr_io_signature_sptr output_signature,
				      unsigned decimation)
  : gr_sync_block (name, input_signature, output_signature)
{
  set_decimation (decimation);
}

void
gr_sync_decimator::forecast (int noutput_items, gr_vector_int &ninput_items_required)
{
  unsigned ninputs = ninput_items_required.size ();
  for (unsigned i = 0; i < ninputs; i++)
    ninput_items_required[i] = fixed_rate_noutput_to_ninput(noutput_items);
}

int
gr_sync_decimator::fixed_rate_noutput_to_ninput(int noutput_items)
{
  return noutput_items * decimation() + history() - 1;
}

int
gr_sync_decimator::fixed_rate_ninput_to_noutput(int ninput_items)
{
  return std::max(0, ninput_items - (int)history() + 1) / decimation();
}

int
gr_sync_decimator::general_work (int noutput_items,
				 gr_vector_int &ninput_items,
				 gr_vector_const_void_star &input_items,
				 gr_vector_void_star &output_items)
{
  int	r = work (noutput_items, input_items, output_items);
  if (r > 0)
    consume_each (r * decimation ());
  return r;
}