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/* -*- c++ -*- */
/*
* Copyright 2010 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_DIGITAL_CPMMOD_BC_H
#define INCLUDED_DIGITAL_CPMMOD_BC_H
#include <gr_hier_block2.h>
#include <gr_char_to_float.h>
#include <gr_interp_fir_filter_fff.h>
#include <gr_frequency_modulator_fc.h>
#include <gr_cpm.h>
class digital_cpmmod_bc;
typedef boost::shared_ptr<digital_cpmmod_bc> digital_cpmmod_bc_sptr;
digital_cpmmod_bc_sptr
digital_make_cpmmod_bc(int type, float h,
unsigned samples_per_sym,
unsigned L, double beta=0.3);
/*!
* \brief Generic CPM modulator
*
* \ingroup modulation_blk
*
* \param type The modulation type. Can be one of LREC, LRC, LSRC, TFM
* or GAUSSIAN. See gr_cpm::phase_response() for a
* detailed description.
* \param h The modulation index. \f$ h \cdot \pi\f$ is the maximum
* phase change that can occur between two symbols, i.e., if
* you only send ones, the phase will increase by \f$ h \cdot
* \pi\f$ every \p samples_per_sym samples. Set this to 0.5
* for Minimum Shift Keying variants.
* \param samples_per_sym Samples per symbol.
* \param L The length of the phase duration in symbols. For L=1, this
* yields full- response CPM symbols, for L > 1,
* partial-response.
* \param beta For LSRC, this is the rolloff factor. For Gaussian
* pulses, this is the 3 dB time-bandwidth product.
*
* Examples:
* - Setting h = 0.5, L = 1, type = LREC yields MSK.
* - Setting h = 0.5, type = GAUSSIAN and beta = 0.3 yields GMSK
* as used in GSM.
*
* The input of this block are symbols from an M-ary alphabet
* +/-1, +/-3, ..., +/-(M-1). Usually, M = 2 and therefore, the
* valid inputs are +/-1.
* The modulator will silently accept any other inputs, though.
* The output is the phase-modulated signal.
*/
class digital_cpmmod_bc : public gr_hier_block2
{
friend digital_cpmmod_bc_sptr digital_make_cpmmod_bc(int type, float h,
unsigned samples_per_sym,
unsigned L, double beta);
std::vector<float> d_taps;
gr_char_to_float_sptr d_char_to_float;
gr_interp_fir_filter_fff_sptr d_pulse_shaper;
gr_frequency_modulator_fc_sptr d_fm;
protected:
digital_cpmmod_bc(gr_cpm::cpm_type type, float h,
unsigned samples_per_sym,
unsigned L, double beta);
public:
//! Return the phase response FIR taps
std::vector<float> get_taps() { return d_taps; };
};
#endif /* INCLUDED_DIGITAL_CPMMOD_BC_H */
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