3 * Copyright 2002 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
23 #include <atsc_consts.h>
24 #include <atsci_vsbtx_lp.h>
33 // atsc root raised cosine filter, sampling rate = 21.52 MHz
34 static const float atsc_vsbtx_lp2x[] = {
35 #include "atsc_vsbtx_lp.dat"
38 #define NELEM(x) (sizeof (x) / sizeof ((x)[0]))
40 // is a within 5% of target?
43 close_enough_p (double a, double target)
45 double delta = fabs (target * 0.05); // 5 percent
47 return fabs (target - a) <= delta;
51 atsc_vsbtx_lp::taps (double sampling_freq)
53 if (close_enough_p (sampling_freq, 2 * ATSC_SYMBOL_RATE)){
54 return vector<float>(&atsc_vsbtx_lp2x[0], &atsc_vsbtx_lp2x[NELEM(atsc_vsbtx_lp2x)]);
57 throw std::out_of_range (
58 "atsc_vsbtx_lp: no pre-designed filter close enough");