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5dcca89172
RRC filter alone will do the trick!
68 lines
2.9 KiB
C++
68 lines
2.9 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __AIS_BASEBAND_H__
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#define __AIS_BASEBAND_H__
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#include <cstdint>
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#include <cstddef>
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#include <complex>
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#include <array>
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#include <bitset>
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#include <utility>
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namespace baseband {
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namespace ais {
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// RRC length should be about 4 x the symbol length (4T) to do a good job of
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// cleaning up ISI.
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// Translate+RRC filter
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// sample=76.8k, deviation=2400, b=0.5, symbol=9600
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// Length: 32 taps, 4 symbols, 1 cycle of sinusoid
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constexpr std::array<std::complex<float>, 32> rrc_taps_76k8_4t_p { {
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{ 5.3368736990e-03f, 0.0000000000e+00f }, { 4.6850211151e-03f, 9.3190864122e-04f },
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{ 1.7970187432e-03f, 7.4434953528e-04f }, { -2.5478608559e-03f, -1.7024261963e-03f },
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{ -6.6710920858e-03f, -6.6710920858e-03f }, { -8.6960320791e-03f, -1.3014531722e-02f },
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{ -7.5474785839e-03f, -1.8221225159e-02f }, { -3.8115552023e-03f, -1.9161981995e-02f },
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{ -8.1697309033e-19f, -1.3342183083e-02f }, { 3.6940784220e-05f, -1.8571386338e-04f },
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{ -7.5474785839e-03f, 1.8221225159e-02f }, { -2.4954265902e-02f, 3.7346698152e-02f },
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{ -5.1450054092e-02f, 5.1450054092e-02f }, { -8.3018814119e-02f, 5.5471398140e-02f },
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{ -1.1321218147e-01f, 4.6894020990e-02f }, { -1.3498960022e-01f, 2.6851100952e-02f },
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{ -1.4292666316e-01f, 1.7503468055e-17f }, { -1.3498960022e-01f, -2.6851100952e-02f },
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{ -1.1321218147e-01f, -4.6894020990e-02f }, { -8.3018814119e-02f, -5.5471398140e-02f },
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{ -5.1450054092e-02f, -5.1450054092e-02f }, { -2.4954265902e-02f, -3.7346698152e-02f },
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{ -7.5474785839e-03f, -1.8221225159e-02f }, { 3.6940784220e-05f, 1.8571386338e-04f },
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{ 2.4509192710e-18f, 1.3342183083e-02f }, { -3.8115552023e-03f, 1.9161981995e-02f },
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{ -7.5474785839e-03f, 1.8221225159e-02f }, { -8.6960320791e-03f, 1.3014531722e-02f },
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{ -6.6710920858e-03f, 6.6710920858e-03f }, { -2.5478608559e-03f, 1.7024261963e-03f },
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{ 1.7970187432e-03f, -7.4434953528e-04f }, { 4.6850211151e-03f, -9.3190864122e-04f },
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} };
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using decoded_packet = std::pair<std::string, std::string>;
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decoded_packet packet_decode(const std::bitset<1024>& data, const size_t data_length);
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} /* namespace ais */
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} /* namespace baseband */
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#endif/*__AIS_BASEBAND_H__*/
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