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Diffstat (limited to 'gr-digital/include/digital_cpmmod_bc.h')
-rw-r--r-- | gr-digital/include/digital_cpmmod_bc.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/gr-digital/include/digital_cpmmod_bc.h b/gr-digital/include/digital_cpmmod_bc.h new file mode 100644 index 000000000..4e9547cd6 --- /dev/null +++ b/gr-digital/include/digital_cpmmod_bc.h @@ -0,0 +1,96 @@ +/* -*- 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 <digital_api.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_API 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_API digital_cpmmod_bc : public gr_hier_block2 +{ + friend DIGITAL_API 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 */ + |