mayhem-firmware/firmware/application/tuning.cpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * This file is part of PortaPack.
 *
 * 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 2, 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; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "tuning.hpp"

#include "utility.hpp"

namespace tuning {
namespace config {

namespace {

constexpr rf::Frequency low_band_second_lo_frequency(const rf::Frequency target_frequency) {
    return 2650000000 - (target_frequency / 7);
}

constexpr rf::Frequency high_band_second_lo_regions_2_and_3(const rf::Frequency target_frequency) {
    return (target_frequency < 5100000000)
               ? (2350000000 + ((target_frequency - 3600000000) / 5))
               : (2500000000 + ((target_frequency - 5100000000) / 9));
}

constexpr rf::Frequency high_band_second_lo_frequency(const rf::Frequency target_frequency) {
    return (target_frequency < 3600000000)
               ? (2170000000 + (((target_frequency - 2740000000) * 57) / 86))
               : high_band_second_lo_regions_2_and_3(target_frequency);
}

Config low_band(const rf::Frequency target_frequency) {
    const rf::Frequency first_lo_frequency = target_frequency + low_band_second_lo_frequency(target_frequency);
    const rf::Frequency second_lo_frequency = first_lo_frequency - target_frequency;
    const bool mixer_invert = true;
    return {first_lo_frequency, second_lo_frequency, rf::path::Band::Low, mixer_invert};
}

Config mid_band(const rf::Frequency target_frequency) {
    return {0, target_frequency, rf::path::Band::Mid, false};
}

Config high_band(const rf::Frequency target_frequency) {
    const rf::Frequency first_lo_frequency = target_frequency - high_band_second_lo_frequency(target_frequency);
    const rf::Frequency second_lo_frequency = target_frequency - first_lo_frequency;
    const bool mixer_invert = false;
    return {first_lo_frequency, second_lo_frequency, rf::path::Band::High, mixer_invert};
}

} /* namespace */

Config create(const rf::Frequency target_frequency) {
    /* TODO: This is some lame code. */
    if (rf::path::band_low.contains(target_frequency)) {
        return low_band(target_frequency);
    } else if (rf::path::band_mid.contains(target_frequency)) {
        return mid_band(target_frequency);
    } else if (rf::path::band_high.contains(target_frequency)) {
        return high_band(target_frequency);
    } else {
        return {};
    }
}

} /* namespace config */
} /* namespace tuning */