/* -*- 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 #include #include using std::vector; using std::cerr; using std::endl; vector atsc_root_raised_cosine_bandpass::taps (double sampling_freq) { vector t = atsc_root_raised_cosine::taps (sampling_freq); cerr << "atsc_root_raised_cosine_bandpass::taps -- " << t.size () << endl; // heterodyne the low pass coefficients up to the specified bandpass // center frequency. Note that when we do this, the filter bandwidth // is effectively twice the low pass (2.69 * 2 = 5.38) and hence // matches the diagram in the ATSC spec. double arg = 2 * M_PI * _center_freq / sampling_freq; for (unsigned int i = 0; i < t.size (); i++) // the factor of 2 keeps the gain of the passband normalized to 1 t[i] *= 2 * cos (arg * (double) i); return t; }