/***************************************************************************
 *   Copyright (C) 2021 - 2023 by Federico Amedeo Izzo IU2NUO,             *
 *                                Niccolò Izzo IU2KIN                      *
 *                                Frederik Saraci IU2NRO                   *
 *                                Silvano Seva IU2KWO                      *
 *                                                                         *
 *                                                                         *
 *   This program 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 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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 this program; if not, see <http://www.gnu.org/licenses/>   *
 ***************************************************************************/

#include <limits.h>
#include <inttypes.h>
#include <stdio.h>
#include <M17/M17DSP.h>

#define IMPULSE_SIZE 4096

using namespace std;

/**
 * Test the different demodulation steps
 */

int main()
{
    // Open file
    FILE *baseband_out = fopen("M17_rrc_impulse_response.raw", "wb");
    if (!baseband_out)
    {
        perror("Error in opening output file");
        return -1;
    }

    // Allocate impulse signal
    int16_t impulse[IMPULSE_SIZE] = { 0 };
    impulse[0] = SHRT_MAX;

    // Apply RRC on impulse signal
    int16_t filtered_impulse[IMPULSE_SIZE] = { 0 };
    for(size_t i = 0; i < IMPULSE_SIZE; i++)
    {
        float elem = static_cast< float >(impulse[i]);
        filtered_impulse[i] = static_cast< int16_t >(M17::rrc(0.10 * elem));
    }
    fwrite(filtered_impulse, IMPULSE_SIZE, 1, baseband_out);
    fclose(baseband_out);
    return 0;
}
