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/* -*- c++ -*- */
/*
* Copyright 2013 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.
*/
#ifndef INCLUDED_DIGITAL_OFDM_CYCLIC_PREFIXER_H
#define INCLUDED_DIGITAL_OFDM_CYCLIC_PREFIXER_H
#include <digital/api.h>
#include <gr_tagged_stream_block.h>
namespace gr {
namespace digital {
/*!
* \brief Adds a cyclic prefix and performs pulse shaping on OFDM symbols.
* \ingroup ofdm_blk
*
* Input: OFDM symbols (in the time domain, i.e. after the IFFT). Optionally,
* entire frames can be processed. In this case, \p len_tag_key must be
* specified which holds the key of the tag that denotes how
* many OFDM symbols are in a frame.
* Output: A stream of (scalar) complex symbols, which include the cyclic prefix
* and the pulse shaping.
* Note: If complete frames are processed, and \p rolloff_len is greater
* than zero, the final OFDM symbol is followed by the delay line of
* the pulse shaping.
*
* The pulse shape is a raised cosine in the time domain.
*/
class DIGITAL_API ofdm_cyclic_prefixer : virtual public gr_tagged_stream_block
{
public:
typedef boost::shared_ptr<ofdm_cyclic_prefixer> sptr;
/*!
* \param input_size FFT length (i.e. length of the OFDM symbols)
* \param output_size FFT length + cyclic prefix length (in samples)
* \param rolloff_len Length of the rolloff flank in samples
* \param len_tag_key For framed processing the key of the length tag
*/
static sptr make(
size_t input_size,
size_t output_size,
int rolloff_len=0,
const std::string &len_tag_key=""
);
};
} // namespace digital
} // namespace gr
#endif /* INCLUDED_DIGITAL_OFDM_CYCLIC_PREFIXER_H */
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