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/*
* Copyright 2004,2006,2007 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 <pager_slicer_fb.h>
#include <gr_io_signature.h>
pager_slicer_fb_sptr pager_make_slicer_fb(float alpha)
{
return pager_slicer_fb_sptr(new pager_slicer_fb(alpha));
}
pager_slicer_fb::pager_slicer_fb(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;
}
// Tracks average, minimum, and peak, then converts input into one of:
//
// [0, 1, 2, 3]
unsigned char pager_slicer_fb::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 pager_slicer_fb::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;
}
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