root/experimental/components/Demodulator/src/DemodulatorDSP.h @ 3998

/****************************************************************************

Copyright 2007 Virginia Polytechnic Institute and State University

This file is part of the OSSIE Demodulator.

OSSIE Demodulator 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 of the License, or
(at your option) any later version.

OSSIE Demodulator 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 OSSIE Demodulator; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

****************************************************************************/


#ifndef __DEMODULATORDSP_IMPL_H__
#define __DEMODULATORDSP_IMPL_H__

#include <stdlib.h>
#include "sigproc/SigProc.h"

#define BIT0 0
#define BIT1 1

#define TARGET_SIGNAL_ENERGY 10000

#define DEMOD_COS_22_5 0.923879532511287
#define DEMOD_SIN_22_5 0.382683432365090

#define QAM16_THRESHOLD 6324    ///< 16-QAM threshold for RMS=10000 signal
#define PAM4_THRESHOLD 8944     ///< 4-PAM threshold for RMS=10000 signal

/// Modulation scheme
enum ModulationScheme {
    MOD_BPSK,
    MOD_QPSK,
    MOD_8PSK,
    MOD_16QAM,
    MOD_4PAM,
    MOD_DBPSK,
    MOD_DQPSK,
    MOD_D8PSK
};

/** \brief 
 *
 *
 */
class DemodulatorDSP
{
  public:
    /// Initializing constructor
    DemodulatorDSP();

    /// Destructor
    ~DemodulatorDSP();

    /// Set modulation scheme
    void SetModulationScheme(ModulationScheme _ms);

    /// Demodulates sequence of symbols
    void DemodulateSequence(
        short * I_in,
        short * Q_in,
        unsigned int N_in,
        char * bits_out);

  protected:
    /// Demodulation function pointer
    void (*Demodulate) (
        short & I_in,
        short & Q_in,
        char * bits_out);

    ///
    ///\todo check amplitude correction method
    void ScaleSignalAmplitude(
        short * I_in,
        short * Q_in,
        unsigned int N_in,
        unsigned int targetEnergy);

    unsigned int bitsPerSymbol;     ///< Number of bits represented by each symbol
    short state_i;                  ///< In-phase state for differential mode
    short state_q;                  ///< Quadrature state for differential mode
    ModulationScheme mod_scheme;    ///< Current (de)modulation scheme
    bool differentialMode;          ///< Differential PSK mode flag

  private:
    /// Disallow copy constructor
    DemodulatorDSP(DemodulatorDSP&);

};

#endif

///
void DemodulateBPSK(
    short & I_in,
    short & Q_in,
    char * bits_out);

///
void DemodulateQPSK(
    short & I_in,
    short & Q_in,
    char * bits_out);

///
void Demodulate8PSK(
    short & I_in,
    short & Q_in,
    char * bits_out);

///
void Demodulate16QAM(
    short & I_in,
    short & Q_in,
    char * bits_out);

///
void Demodulate4PAM(
    short & I_in,
    short & Q_in,
    char * bits_out);