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/* -*- c++ -*- */
/*
* Copyright 2010,2012 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 <digital/api.h>
#include <gr_hier_block2.h>
#include <analog/cpm.h>
namespace gr {
namespace digital {
/*!
* \brief Generic CPM modulator
*
* \ingroup modulation_blk
* \ingroup digital
*
* 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_API cpmmod_bc : virtual public gr_hier_block2
{
public:
// gr::digital::cpmmod_bc::sptr
typedef boost::shared_ptr<cpmmod_bc> sptr;
/*!
* Make CPM modulator block.
*
* \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.
*/
static sptr make(analog::cpm::cpm_type type, float h,
int samples_per_sym,
int L, double beta=0.3);
/*!
* Make GMSK modulator block.
*
* The type is GAUSSIAN and the modulation index for GMSK is
* 0.5. This are populated automatically by this factory
* function.
*
* \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.
*/
static sptr make_gmskmod_bc(int samples_per_sym=2,
int L=4, double beta=0.3);
//! Return the phase response FIR taps
virtual std::vector<float> taps() const = 0;
//! Return the type of CPM modulator
virtual int type() const = 0;
//! Return the modulation index of the modulator.
virtual float index() const = 0;
//! Return the number of samples per symbol
virtual int samples_per_sym() const = 0;
//! Return the length of the phase duration (in symbols)
virtual int length() const = 0;
//! Return the value of beta for the modulator
virtual double beta() const = 0;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_DIGITAL_CPMMOD_BC_H */
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