GNU Radio's DAB Package
dab_ofdm_coarse_frequency_correct.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2004 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
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)
10 * any later version.
11 *
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.
16 *
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.
21 */
22#ifndef INCLUDED_DAB_OFDM_COARSE_FREQUENCY_CORRECT_H
23#define INCLUDED_DAB_OFDM_COARSE_FREQUENCY_CORRECT_H
24
25#include <gr_sync_block.h>
26
28
29typedef std::shared_ptr<dab_ofdm_coarse_frequency_correct> dab_ofdm_coarse_frequency_correct_sptr;
30
31dab_ofdm_coarse_frequency_correct_sptr
33 unsigned int num_carriers);
34
35/*!
36 * \brief Corrects coarse frequency offset in the frequency spectrum.
37 * \ingroup DAB
38 *
39 * \param fft_length total number of fft bins
40 * \param num_carriers number of carriers with OFDM symbols, not including the zero carrier
41 *
42 * This block detects where the signal is (coarse frequency offset) by looking
43 * at the energy and returns only the carriers containing information (i.e. it
44 * removes the zeros on the left, the zeros on the right and the one zero
45 * carrier in the middle).
46 */
47class dab_ofdm_coarse_frequency_correct : public gr_sync_block
48{
49 private:
50 // The friend declaration allows dab_make_ofdm_coarse_frequency_correct to
51 // access the private constructor.
52
53 friend dab_ofdm_coarse_frequency_correct_sptr
54 dab_make_ofdm_coarse_frequency_correct (unsigned int fft_length, unsigned int num_carriers);
55
56 float mag_squared(const gr_complex sample);
57 dab_ofdm_coarse_frequency_correct (unsigned int fft_length, unsigned int num_carriers); // private constructor
58 void correlate_energy(const gr_complex *symbol);
59
60 unsigned int d_fft_length;
61 unsigned int d_num_carriers;
62 unsigned int d_zeros_on_left;
63 unsigned int d_freq_offset;
64
65 public:
66 int work (int noutput_items,
67 gr_vector_const_void_star &input_items,
68 gr_vector_void_star &output_items);
69};
70
71#endif /* INCLUDED_DAB_OFDM_COARSE_FREQUENCY_CORRECT_H */
Corrects coarse frequency offset in the frequency spectrum.
Definition dab_ofdm_coarse_frequency_correct.h:48
int work(int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
friend dab_ofdm_coarse_frequency_correct_sptr dab_make_ofdm_coarse_frequency_correct(unsigned int fft_length, unsigned int num_carriers)
dab_ofdm_coarse_frequency_correct_sptr dab_make_ofdm_coarse_frequency_correct(unsigned int fft_length, unsigned int num_carriers)