3 * Copyright 2007 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.
27 #include <gr_pn_correlator_cc.h>
28 #include <gr_io_signature.h>
30 gr_pn_correlator_cc_sptr
31 gr_make_pn_correlator_cc(int degree, int mask, int seed)
33 return gr_pn_correlator_cc_sptr (new gr_pn_correlator_cc(degree, mask, seed));
36 gr_pn_correlator_cc::gr_pn_correlator_cc(int degree, int mask, int seed)
37 : gr_sync_decimator ("pn_correlator_cc",
38 gr_make_io_signature (1, 1, sizeof(gr_complex)),
39 gr_make_io_signature (1, 1, sizeof(gr_complex)),
40 (unsigned int)((1ULL << degree)-1)) // PN code length
42 d_len = (unsigned int)((1ULL << degree)-1);
44 mask = gri_glfsr::glfsr_mask(degree);
45 d_reference = new gri_glfsr(mask, seed);
46 for (int i = 0; i < d_len; i++) // initialize to last value in sequence
47 d_pn = 2.0*d_reference->next_bit()-1.0;
50 gr_pn_correlator_cc::~gr_pn_correlator_cc()
56 gr_pn_correlator_cc::work(int noutput_items,
57 gr_vector_const_void_star &input_items,
58 gr_vector_void_star &output_items)
60 const gr_complex *in = (const gr_complex *) input_items[0];
61 gr_complex *out = (gr_complex *) output_items[0];
64 for (int i = 0; i < noutput_items; i++) {
67 for (int j = 0; j < d_len; j++) {
68 if (j != 0) // retard PN generator one sample per period
69 d_pn = 2.0*d_reference->next_bit()-1.0; // no conditionals
73 *out++ = sum*gr_complex(1.0/d_len, 0.0);