portapack-mayhem/firmware/baseband/channel_decimator.hpp

/*
 * 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.
 */

#ifndef __CHANNEL_DECIMATOR_H__
#define __CHANNEL_DECIMATOR_H__

#include "buffer.hpp"
#include "complex.hpp"

#include "dsp_decimate.hpp"

#include <array>

class ChannelDecimator {
   public:
    enum class DecimationFactor {
        By2,
        By4,
        By8,
        By16,
        By32,
    };

    constexpr ChannelDecimator(
        const DecimationFactor decimation_factor,
        const bool fs_over_4_downconvert = true)
        : decimation_factor{decimation_factor},
          fs_over_4_downconvert{fs_over_4_downconvert} {
    }

    void set_decimation_factor(const DecimationFactor f) {
        decimation_factor = f;
    }

    buffer_c16_t execute(const buffer_c8_t& buffer) {
        auto decimated = execute_decimation(buffer);

        return decimated;
    }

   private:
    std::array<complex16_t, 1024> work_baseband{};

    dsp::decimate::TranslateByFSOver4AndDecimateBy2CIC3 translate{};
    dsp::decimate::Complex8DecimateBy2CIC3 cic_0{};
    dsp::decimate::DecimateBy2CIC3 cic_1{};
    dsp::decimate::DecimateBy2CIC3 cic_2{};
    dsp::decimate::DecimateBy2CIC3 cic_3{};
    dsp::decimate::DecimateBy2CIC3 cic_4{};

    DecimationFactor decimation_factor{DecimationFactor::By32};
    const bool fs_over_4_downconvert{true};

    buffer_c16_t execute_decimation(const buffer_c8_t& buffer);

    buffer_c16_t execute_stage_0(
        const buffer_c8_t& buffer,
        const buffer_c16_t& work_baseband_buffer);
};

#endif /*__CHANNEL_DECIMATOR_H__*/