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/* -*- c++ -*- */
/* Copyright 2012 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gr_io_signature.h>
#include "digital_ofdm_sync_sc_cfb.h"
#include <gr_delay.h>
#include <blocks/conjugate_cc.h>
#include <blocks/multiply_cc.h>
#include <filter/fir_filter_ccf.h>
#include <blocks/complex_to_mag_squared.h>
#include <filter/fir_filter_fff.h>
#include <blocks/multiply_ff.h>
#include <blocks/divide_ff.h>
#include <blocks/complex_to_arg.h>
#include <blocks/plateau_detector_fb.h>
#include <gr_sample_and_hold_ff.h>
// Define this to add a third output for debugging
//#define SYNC_ADD_DEBUG_OUTPUT
digital_ofdm_sync_sc_cfb_sptr
digital_make_ofdm_sync_sc_cfb (int fft_len, int cp_len)
{
return gnuradio::get_initial_sptr (new digital_ofdm_sync_sc_cfb(fft_len, cp_len));
}
digital_ofdm_sync_sc_cfb::digital_ofdm_sync_sc_cfb (int fft_len, int cp_len)
: gr_hier_block2 ("ofdm_sync_sc_cfb",
gr_make_io_signature(1, 1, sizeof (gr_complex)),
#ifndef SYNC_ADD_DEBUG_OUTPUT
gr_make_io_signature2(2, 2, sizeof (float), sizeof (unsigned char)))
#else
gr_make_io_signature3(3, 3, sizeof (float), sizeof (unsigned char), sizeof (float)))
#endif
{
std::vector<float> ma_taps(fft_len/2, 1.0);
gr_delay_sptr delay(gr_make_delay(sizeof(gr_complex), fft_len/2));
gr::blocks::conjugate_cc::sptr delay_conjugate(gr::blocks::conjugate_cc::make());
gr::blocks::multiply_cc::sptr delay_corr(gr::blocks::multiply_cc::make());
gr::filter::fir_filter_ccf::sptr delay_ma(gr::filter::fir_filter_ccf::make(1, std::vector<float>(fft_len/2, 1.0)));
gr::blocks::complex_to_mag_squared::sptr delay_magsquare(gr::blocks::complex_to_mag_squared::make());
gr::blocks::divide_ff::sptr delay_normalize(gr::blocks::divide_ff::make());
gr::blocks::complex_to_mag_squared::sptr normalizer_magsquare(gr::blocks::complex_to_mag_squared::make());
gr::filter::fir_filter_fff::sptr normalizer_ma(gr::filter::fir_filter_fff::make(1, std::vector<float>(fft_len, 0.5)));
gr::blocks::multiply_ff::sptr normalizer_square(gr::blocks::multiply_ff::make());
gr::blocks::complex_to_arg::sptr peak_to_angle(gr::blocks::complex_to_arg::make());
gr_sample_and_hold_ff_sptr sample_and_hold(gr_make_sample_and_hold_ff());
gr::blocks::plateau_detector_fb::sptr plateau_detector(gr::blocks::plateau_detector_fb::make(cp_len));
// Delay Path
connect(self(), 0, delay, 0);
connect(delay, 0, delay_conjugate, 0);
connect(delay_conjugate, 0, delay_corr, 1);
connect(self(), 0, delay_corr, 0);
connect(delay_corr, 0, delay_ma, 0);
connect(delay_ma, 0, delay_magsquare, 0);
connect(delay_magsquare, 0, delay_normalize, 0);
// Energy Path
connect(self(), 0, normalizer_magsquare, 0);
connect(normalizer_magsquare, 0, normalizer_ma, 0);
connect(normalizer_ma, 0, normalizer_square, 0);
connect(normalizer_ma, 0, normalizer_square, 1);
connect(normalizer_square, 0, delay_normalize, 1);
// Fine frequency estimate (output 0)
connect(delay_ma, 0, peak_to_angle, 0);
connect(peak_to_angle, 0, sample_and_hold, 0);
connect(sample_and_hold, 0, self(), 0);
// Peak detect (output 1)
connect(delay_normalize, 0, plateau_detector, 0);
connect(plateau_detector, 0, sample_and_hold, 1);
connect(plateau_detector, 0, self(), 1);
#ifdef SYNC_ADD_DEBUG_OUTPUT
// Debugging: timing metric (output 2)
connect(delay_normalize, 0, self(), 2);
#endif
}
digital_ofdm_sync_sc_cfb::~digital_ofdm_sync_sc_cfb()
{
}
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