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/* -*- c++ -*- */
/*
* Copyright 2006,2010 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 <atsc_bit_timing_loop.h>
#include <gr_io_signature.h>
#include <atsc_consts.h>
#include <string.h>
// Input rate changed from 20MHz to 19.2 to support usrp at 3 * 6.4MHz
float input_rate = 19.2e6;
double ratio_of_rx_clock_to_symbol_freq = input_rate / ATSC_SYMBOL_RATE;
atsc_bit_timing_loop_sptr
atsc_make_bit_timing_loop()
{
return gnuradio::get_initial_sptr(new atsc_bit_timing_loop());
}
atsc_bit_timing_loop::atsc_bit_timing_loop()
: gr_block("atsc_bit_timing_loop",
gr_make_io_signature(1, 1, sizeof(float)),
gr_make_io_signature3(2, 3, sizeof(float), sizeof(float), sizeof(float))),
d_interp(ratio_of_rx_clock_to_symbol_freq), d_next_input(0),
d_rx_clock_to_symbol_freq (ratio_of_rx_clock_to_symbol_freq),
d_si(0)
{
reset();
}
void
atsc_bit_timing_loop::forecast (int noutput_items, gr_vector_int &ninput_items_required)
{
unsigned ninputs = ninput_items_required.size();
for (unsigned i = 0; i < ninputs; i++)
ninput_items_required[i] = static_cast<int>(noutput_items * d_rx_clock_to_symbol_freq) + 1500 - 1;
}
int
atsc_bit_timing_loop::general_work (int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
int r = work (noutput_items, input_items, output_items);
if (r > 0)
consume_each (d_si);
return r;
}
int
atsc_bit_timing_loop::work (int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const float *in = (const float *) input_items[0];
float *out_sample = (float *) output_items[0];
atsc::syminfo *out_tag = (atsc::syminfo *) output_items[1];
float *out_timing_error = (float *) output_items[2];
assert(sizeof(float) == sizeof(atsc::syminfo));
// We are tasked with producing output.size output samples.
// We will consume approximately 2 * output.size input samples.
int k; // output index
float interp_sample;
int symbol_index;
double timing_adjustment = 0;
bool seg_locked;
atsc::syminfo tag;
// ammount requested in forecast
unsigned long input_size = noutput_items * d_rx_clock_to_symbol_freq + 1500 -1;
memset (&tag, 0, sizeof (tag));
// ammount actually consumed
d_si = 0;
for (k = 0; k < noutput_items; k++){
if (!d_interp.update (in, input_size, &d_si, timing_adjustment, &interp_sample)){
fprintf (stderr, "GrAtscBitTimingLoop3: ran short on data...\n");
break;
}
d_sssr.update (interp_sample, &seg_locked, &symbol_index, &timing_adjustment);
if (output_items.size() == 3) {
out_timing_error[k] = timing_adjustment;
}
out_sample[k] = interp_sample;
tag.valid = seg_locked;
tag.symbol_num = symbol_index;
out_tag[k] = tag;
}
return k;
}
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