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/* -*- 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.
*/
#include <atsc_consts.h>
#include <atsci_vsbtx_lp.h>
#include <stdexcept>
#include <cmath>
#include <iostream>
using std::vector;
using std::cerr;
using std::endl;
// atsc root raised cosine filter, sampling rate = 21.52 MHz
static const float atsc_vsbtx_lp2x[] = {
#include "atsc_vsbtx_lp.dat"
};
#define NELEM(x) (sizeof (x) / sizeof ((x)[0]))
// is a within 5% of target?
static bool
close_enough_p (double a, double target)
{
double delta = fabs (target * 0.05); // 5 percent
return fabs (target - a) <= delta;
}
vector<float>
atsc_vsbtx_lp::taps (double sampling_freq)
{
if (close_enough_p (sampling_freq, 2 * ATSC_SYMBOL_RATE)){
return vector<float>(&atsc_vsbtx_lp2x[0], &atsc_vsbtx_lp2x[NELEM(atsc_vsbtx_lp2x)]);
}
else
throw std::out_of_range (
"atsc_vsbtx_lp: no pre-designed filter close enough");
}
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