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/* -*- c++ -*- */
/*
* Copyright 2004,2006,2007,2010,2012 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 "slicer_fb_impl.h"
#include <gr_io_signature.h>
namespace gr {
namespace pager {
slicer_fb::sptr
slicer_fb::make(float alpha)
{
return gnuradio::get_initial_sptr
(new slicer_fb_impl(alpha));
}
slicer_fb_impl::slicer_fb_impl(float alpha) :
gr_sync_block("slicer_fb",
gr_make_io_signature(1, 1, sizeof(float)),
gr_make_io_signature(1, 1, sizeof(unsigned char)))
{
d_alpha = alpha;
d_beta = 1.0-alpha;
d_avg = 0.0;
}
slicer_fb_impl::~slicer_fb_impl()
{
}
// Tracks average, minimum, and peak, then converts input into one of:
//
// [0, 1, 2, 3]
unsigned char
slicer_fb_impl::slice(float sample)
{
unsigned char decision;
// Update DC level and remove
d_avg = d_avg*d_beta+sample*d_alpha;
sample -= d_avg;
if(sample > 0) {
if(sample > 2.0)
decision = 3;
else
decision = 2;
}
else {
if(sample < -2.0)
decision = 0;
else
decision = 1;
}
return decision;
}
int
slicer_fb_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
float *iptr = (float *)input_items[0];
unsigned char *optr = (unsigned char *)output_items[0];
int size = noutput_items;
for(int i = 0; i < size; i++)
*optr++ = slice(*iptr++);
return noutput_items;
}
} /* namespace pager */
} /* namespace gr */
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