diff options
Diffstat (limited to 'gr-atsc/lib/atsci_vsbtx_lp.cc')
-rw-r--r-- | gr-atsc/lib/atsci_vsbtx_lp.cc | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/gr-atsc/lib/atsci_vsbtx_lp.cc b/gr-atsc/lib/atsci_vsbtx_lp.cc new file mode 100644 index 0000000000..4b6f82af3d --- /dev/null +++ b/gr-atsc/lib/atsci_vsbtx_lp.cc @@ -0,0 +1,59 @@ +/* -*- 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 <atsc/vsbtx_lp_impl.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"); +} |